Can we 'twist' a digital picture to be square with the camera?
maryanne kehoe
Can we 'twist' the digital photo to be square with the camera?
I must be doing something wrong. When I edit my digital photographs of my
watercolor paintings, I need to crop the photo but I can NEVER get the crop
edges to be exactly square with the digital camera photograph of the
painting.
Therefore I always find myself losing a few millimeters of painting so that
the photograph is square. What am I doing wrong?
Here is how I take the picture.
a) I put my unmatted 30 inch by 22.5 inch watercolor on a white towel lying
on the ground
b) I stand over the painting, sometimes on a step stool, and position the
Canon PowerShot A95 5MP camera over the center of the painting
c) I snap the shot using flash & macro focus making sure I am as square as
possible and taking an extra inch or so of border all around to facilitate
cropping
Back inside the office, each and every time, when I crop the 2592 by 1944
pixel digital results using Irvanview 3.98 on Windows XP, I end up with
edges that are not square at first. I have to lose some of my precious
painting just to get square edges when I crop.
What am I doing wrong?
What's the trick to get a photo that is head-on with the painting?
Is there a way to twist the painting with software so I don't have to crop
edges and lose painting data?
2
news:1lqfc4lyhulse$.1su66j5z1ku9i$.dlg@40tude.net...
> What 'trick' am I missing to take a photo of my watercolor paintings?
> Can we 'twist' the digital photo to be square with the camera?
It seems you have a viewfinder that is not accurate - shows more coverage
than is there, and/or distortion is having its way. You should not need
macro-mode for such pictures, either.
Hang the painting on a wall. Shoot with a tripod. Leave the camera on the
tripod and check the photos. Adjust until it is correct and leave it there
for the pictures.
Trev
"maryanne kehoe" <atl...@webtv.net> wrote in message
news:1lqfc4lyhulse$.1su66j5z1ku9i$.dlg@40tude.net...
Well you can rotate if its not SQ or maybe you have a ratio of width to
height that's the problem As I cant see your image I dont know What size are
you cropping the 2592*1944 image to.
PSP has straightening and parallax correction tools. Does your picture
have more white border at one side then the others.
Derek Fountain
Your description suggests you're seeing barrel distortion, which is an
effect of the lens. Have a look at this page from DPReview's review of
your camera:
http://www.dpreview.com/reviews/canona95/page5.asp
Scroll down to the Macro Focus and Barrel and Pincushion Distortion
sections - is that what you're seeing?
To minimise the effect, start by switching macro mode off. I don't know
why you're using that. Second, if possible get further away from your
painting and zoom in on it a bit. This will be easier if you hang it on
a wall. Your camera shows less distortion when it's not at its widest
zoom setting. Failing that, you'll need to use an image processing tool
to correct the distortion.
Bart van der Wolf
"2" <nh...@droffats.ten> wrote in message
news:128q5mj...@news.supernews.com...
> "maryanne kehoe" <atl...@webtv.net> wrote in message
> news:1lqfc4lyhulse$.1su66j5z1ku9i$.dlg@40tude.net...
>> What 'trick' am I missing to take a photo of my watercolor
>> paintings?
>> Can we 'twist' the digital photo to be square with the camera?
>
> It seems you have a viewfinder that is not accurate - shows more
> coverage than is there, and/or distortion is having its way. You
> should not need macro-mode for such pictures, either.
Either that, or the subject and sensor planes are not parallel.
That is easy to get quite accurate by replacing the paintings by, or
put in front of the painting, a mirror (tile),absolutely parallel to
the painting's surface. If the camera lens is imaged dead center in
the viewfinder (and assuming parallax shift is taken into account),
every thing shouls square out except for lens distortions.
Bart
Bart
CB
absolutely square, and that the camera is centered on the image. Handy tools
are an easel for the painting, a tripod for the camera, a good level, a
measuring tape, and a carpenter's square.
If you get something like Photoshop or PhotoImpact OTOH, you can correct the
misalignment in software.
Cheers;
CB
"maryanne kehoe" <atl...@webtv.net> wrote in message
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babalo...@hotmail.com
maryanne kehoe wrote:
> What 'trick' am I missing to take a photo of my watercolor paintings?
> Can we 'twist' the digital photo to be square with the camera?
>
there will be some loss of image quality (possibly extremely minor but
it will be there). If this is something you do a lot you might want to
consider a copy stand although a copy stand large enough to accomodate
your canvas and give you enough height to use a lens that will not
cause distortion (I would aim for using a 40 - 60mm after taking crop
factor into account) will not be cheap. A tripod and a wall will
probably be better than the sytem you are using but you will still have
geometry problems and repeatability will be difficult. That is where
copy stands come in. Copy stands will also have facilities for various
lighting set-ups.
tomm42
There are two problems you are running into:
1) Alignment of the painting to the sensor plane
2) Distortion from the lens
What to do?
There are several ways to align a painting/sensor. The mirror method
has been posted, I find it inaccurate (does work for some). One thing
needed is a tripod so you can fix the camera in one place, shooting by
hand means every picture will have a different alignment. I place the
painting on an easel, make sure the center and edges are parallel to
the camera lens, use an angle finder (available for $6-$10 at a
hardware store) Make sure the lens and painting are at the
corresponding angles. This is more involved than what can be covered
here and is described in a Kodak book on photographic reproduction.
The lens problem comes from using a zoom lens, most zoom lenses have
distortion throughout their range, most common are barrel and pincusion
distortions. Depending on the quality of the lens these distortions are
better controlled with the more expensive lenes are almost distortion
free. The other distortion in copying flat objects is field curvature,
this is maybe desirable in general picture taking, but annoying in
reproduction work. Both of these problems are cured by using a true
macro lens. this unfortunately is not an option with your A95.
Best thing for you to do is get a decent tripod and work on getting the
painting and sensor aligned. Do not use software to correct the
alignment as that enters other distortions into the image.
Tom
Neil Harrington
"maryanne kehoe" <atl...@webtv.net> wrote in message
news:1lqfc4lyhulse$.1su66j5z1ku9i$.dlg@40tude.net...
> Can we 'twist' the digital photo to be square with the camera?
>
> I must be doing something wrong. When I edit my digital photographs of my
> watercolor paintings, I need to crop the photo but I can NEVER get the
> crop
> edges to be exactly square with the digital camera photograph of the
> painting.
>
> Therefore I always find myself losing a few millimeters of painting so
> that
> the photograph is square. What am I doing wrong?
>
> Here is how I take the picture.
> a) I put my unmatted 30 inch by 22.5 inch watercolor on a white towel
> lying
> on the ground
> b) I stand over the painting, sometimes on a step stool, and position the
> Canon PowerShot A95 5MP camera over the center of the painting
> c) I snap the shot using flash & macro focus making sure I am as square as
> possible and taking an extra inch or so of border all around to facilitate
> cropping
>
> Back inside the office, each and every time, when I crop the 2592 by 1944
> pixel digital results using Irvanview 3.98 on Windows XP, I end up with
> edges that are not square at first. I have to lose some of my precious
> painting just to get square edges when I crop.
>
> What am I doing wrong?
For one thing, the fact that you're hand-holding the camera (especially
while standing on a step stool) and trying to shoot straight down must make
it extremely difficult to get the painting square with the camera. Isn't
there some way you can put the watercolor against a vertical surface so you
can use the camera on a tripod? This would make it far easier to get
everything square.
With that size subject I don't know why you're using the macro setting,
though that probably isn't related to your problem. Also unrelated to that,
but isn't flash causing you some problems as well?
> What's the trick to get a photo that is head-on with the painting?
> Is there a way to twist the painting with software so I don't have to crop
> edges and lose painting data?
There is, though there may be a slight loss of image quality (it may not be
noticeable, so might not matter to you at all -- especially with a
watercolor which is usually not a highly detailed subject anyway). Paint
Shop Pro, for example, has a Straighten tool which does exactly what you
want, very easily. No doubt there are other kinds of software that will do
this too.
Ronald Hands
> What 'trick' am I missing to take a photo of my watercolor paintings?
> Can we 'twist' the digital photo to be square with the camera?
As others have mentioned, it's probably barrel distortion that you
are seeing. It is probably most apparent at the wide-angle setting of
your camera.
So I would suggest:
1. Turn off your flash.
2. Turn off macro mode.
3. Hang the painting on a wall, preferably on a north wall outdoors so
that you're shooting it in shade.
4. Zoom the lens out to a medium position, probably the equivalent of
70 or 80 mm in a 35mm camera. Put the camera on a tripod and line it up
with the center of the watercolor.
5. Bracket your exposures if you know how to do that. (You may have to
switch the camera to P mode rather than Auto to use exposure
compensation). Check the histogram which is available on your camera to
make sure you are getting a full range of exposure response.
You're fortunate in that your 30 x 22.5 watercolor is an exact match
for the 4:3 sensor dimensions in your camera, so not much cropping
should be required. I presume you are using the LCD display to frame
your picture. The optical viewfinders in Canon Powershot models show
only about 85 per cent of what you are actually shooting.
My wife shot a bunch of pictures of her favorite Impressionist
paintings in the d'Orsay museum in Paris, using a Canon A40. All of
them show barrel distortion, since she was using wide-angle mode. She
doesn't really care; she's just glad to have them in the album :-)
-- Ron
gpsman
> What 'trick' am I missing to take a photo of my watercolor paintings?
> Can we 'twist' the digital photo to be square with the camera?
I would:
Hang the painting, if I didn't have a copy stand. Use a tripod for the
camera. Align both painting and the camera's back as close as
practical.
Use a medium zoom and mid-aperature settings, not macro.
I'd experiment with lighting and white balance settings. It seems to
me flash might wash out the colors in a watercolor and maybe cause some
reflection.
Use the timer to trip the shutter.
-----
- gpsman
Neil Harrington
"Ronald Hands" <""rhandsNOSPAM\"@mountaincable DOT net"> wrote in message
news:b15e4$448d7ccf$4713089a$24...@MOUNTAINCABLE.NET...
. . .
>
> As others have mentioned, it's probably barrel distortion that you are
> seeing. It is probably most apparent at the wide-angle setting of your
> camera.
Definitely, though that doesn't seem to be what her complaint is. If it is
barrel distortion that's the problem, that can usually be corrected in
software.
2
news:CIqdnfyczJO-GxDZ...@comcast.com...
> Definitely, though that doesn't seem to be what her complaint is. If it is
> barrel distortion that's the problem, that can usually be corrected in
> software.
Correcting barrel or pincushion distortion in software is the last resort of
the scoundrel. I don't know why folks put up with such a waste of time. Get
good lenses and quit spending your life sitting on your butt at a computer
'fixing' things that can be done right the first time.
2
> Oh please. Now tell us exactly what P&S with some optical zoom is free
> from such distortion. Or even which higher end DLSR lens zooms are
> completely free of it. Not everyone is using perfect primes.
You pay one way or the other. Make your choice. It's still just plain nutz
to be spending hours fixing a picture that could have been made once,
properly, in a few minutes.
Dan
wrote:
>I must be doing something wrong. When I edit my digital photographs of my
>watercolor paintings, I need to crop the photo but I can NEVER get the crop
>edges to be exactly square with the digital camera photograph of the
>painting.
PSP makes corners that are mathematically exact right angles. If your
subject doesn't crop to right angles, then the problem is not with
PSP.
1. Lining up your camera and painting may need to be more precise.
It's not easy to get those suckers exactly parallel. 2. Or (perish the
thought!), your painting may be a lttle off-square. 3. Or, maybe your
less-than-$5000 camera lens is producing a small distortion.
In any case, you might not have to reshoot your subject. PSP9 (which
is the version I'm familiar with) has a Perspective Correction tool
that could be enough to satisfy your needs.
--
Regards,
Dan
Alfred Molon
says...
> You pay one way or the other. Make your choice. It's still just plain nutz
> to be spending hours fixing a picture that could have been made once,
> properly, in a few minutes.
What a nonsense.
With the PTLens filter in Photoshop fixing barrel or pincushion
distortion takes a only few seconds. You can even set up an action to
batch correct hundreds of photos.
The only thing you pay is a slight loss in resolution due to the
recalculation of the pixels, but in the era of megapixel cameras with
tons of resolution this is a minor issue.
--
Alfred Molon
------------------------------
Olympus 50X0, 7070, 8080, E300, E330 and E500 forum at
http://groups.yahoo.com/group/MyOlympus/
Olympus E330 resource - http://myolympus.org/E330/
AZ Nomad
>On Mon, 12 Jun 2006 07:05:04 GMT, maryanne kehoe <atl...@webtv.net>
>wrote:
>>I must be doing something wrong. When I edit my digital photographs of my
>>watercolor paintings, I need to crop the photo but I can NEVER get the crop
>>edges to be exactly square with the digital camera photograph of the
>>painting.
>PSP makes corners that are mathematically exact right angles. If your
>subject doesn't crop to right angles, then the problem is not with
>PSP.
Croping to right angles is a trivial operation.
I think you're trying to say something else. Perhaps a
trapezoid->square transform?
Fred Hiltz
> What 'trick' am I missing to take a photo of my watercolor
> paintings? Can we 'twist' the digital photo to be square
> with the camera?
Yes. There are two kinds of distortion to be corrected. PSP does
both.
The first is pincushion or barrel distortion caused by the lens.
Before any cropping or other distortion adjustments, correct it
(from the Adjust > Photo Fix menu) to make the edges of the painting
straight.
The second is pure geometry, a perspective shift caused by the
camera's view point being just a little off center from the
painting. Fetch the Perspective Correction tool. Move the corners of
its rectangle to the four corners of the painting (or any other
places that you know should outline a rectangle). Double click and
magic happens.
--
Fred Hiltz, fhiltz at yahoo dot com
John McWilliams
Is there a rule of thumb that'd tell P+S shooters what focal length
would produce the least distortion?
In fact, I need to review what it is for a DSLR.... I've been using
50mm, but haven't conducted tests to see if that is in fact correct on
the 24-105 ƒ4 IS lens.
--
John McWilliams
John McWilliams
> maryanne kehoe <atl...@webtv.net> wrote:
>> What's the trick to get a photo that is head-on with the painting?
>> Is there a way to twist the painting with software so I don't have to
>> crop edges and lose painting data?
>
>
> than the work, then mounts the work in the center of the drape. The photos
> have a black border, look great, and there is no cropping involved.
>
> In my experience (before I gave up and had a professional do it) you can
> *never* get it so square that you won't lose a little of the work.
How does he have lighting set? Are these unframed oils or watercolors?
Black bg sounds better than white in terms of finished product and
perhaps in terms of reflecting nothing vs. the white. I suppose grey is
another option, or even blue or green, then use PS to remove the bg
entirely.
--
John McWilliams
JoeB
The reason your images aren't square enough to crop is that you
simply are not taking them 100% square on. This being a Paint
Ship Pro group, if you were to purchase Paint Shop Pro 8, 9 or X
(10) you could use the Perspective Correction tool to square the
image before cropping. You would have to make sure that, when
you take the picture, you take the pic so that you've included
some area outside of the painting itself.
Regards,
JoeB
J. Clarke
> Derek Fountain wrote:
>>> What am I doing wrong?
>>
>> Your description suggests you're seeing barrel distortion, which is an
>> effect of the lens. Have a look at this page from DPReview's review of
>> your camera:
>>
>> http://www.dpreview.com/reviews/canona95/page5.asp
>>
>> Scroll down to the Macro Focus and Barrel and Pincushion Distortion
>> sections - is that what you're seeing?
>>
>> To minimise the effect, start by switching macro mode off. I don't know
>> why you're using that. Second, if possible get further away from your
>> painting and zoom in on it a bit. This will be easier if you hang it on
>> a wall. Your camera shows less distortion when it's not at its widest
>> zoom setting. Failing that, you'll need to use an image processing tool
>> to correct the distortion.
>
> Is there a rule of thumb that'd tell P+S shooters what focal length
> would produce the least distortion?
Really depends on the lens. With primes you take what you've got. With
zooms different lenses have a distortion "sweet spot" at different focal
lengths. As a thumb rule longer is better but there are exceptions.
> In fact, I need to review what it is for a DSLR.... I've been using
> 50mm, but haven't conducted tests to see if that is in fact correct on
> the 24-105 ?4 IS lens.
That's really the only way--if you can't find a good distortion test report
then you pretty much have to conduct one yourself.
--
--John
to email, dial "usenet" and validate
(was jclarke at eye bee em dot net)
John McWilliams
> John McWilliams wrote:
>
>> In fact, I need to review what it is for a DSLR.... I've been using
>> 50mm, but haven't conducted tests to see if that is in fact correct on
>> the 24-105 ?4 IS lens.
>
> That's really the only way--if you can't find a good distortion test report
> then you pretty much have to conduct one yourself.
>
Agreed. But I'd still like a rule of thumb for my 20 D. (1.6x factor).
My main lens I'd use is the above mentioned.
--
John McWilliams
John McWilliams
>> What am I doing wrong?
>> What's the trick to get a photo that is head-on with the
> painting?
>> Is there a way to twist the painting with software so I don't
> have to
>> crop edges and lose painting data?
>>
>
> The reason your images aren't square enough to crop is that you
> simply are not taking them 100% square on. This being a Paint
> Ship Pro group, if you were to purchase Paint Shop Pro 8, 9 or X
> (10) you could use the Perspective Correction tool to square the
> image before cropping. You would have to make sure that, when
> you take the picture, you take the pic so that you've included
> some area outside of the painting itself.
>
I don't see PSP in the NG line, and I'd wager that many, if not most, of
us in r.p.d. use Photoshop.
Moreover, there are other phenom described earlier in this thread -
perhaps if you set your newsreader to a threaded mode you would have
seen them....
--
john mcwilliams
Sally Beacham
"maryanne kehoe" <atl...@webtv.net> wrote in message
news:1lqfc4lyhulse$.1su66j5z1ku9i$.dlg@40tude.net...
> What 'trick' am I missing to take a photo of my watercolor paintings?
> Can we 'twist' the digital photo to be square with the camera?
>
Perspective Correction tool, in PSP 8, 9 and X. Then crop as needed. (I
wouldn't let the tool do an auto-crop in this case.)
--
Sally Beacham
www.dizteq.com / www.lvsonline.com
Paint Shop Pro 8 Zero to Hero
Digital Scrapbooking (Course Technology)
J. Clarke
<http://www.photozone.de/8Reviews/lenses/canon_24105_4_is/index.htm> is a
test report on that lens. Seems to have lowest distortion around 40mm.
tomm42
The point is to be done professionally, you don't use Photoshop or
Paintshop Pro, any work here to control perspective will cause a loss
of sharpness in the paintings. Alignment is one of those things once
you figure it out you just go DOH! it is relatively easy. The other
point is the lens, you don't need a $5K lens, you need a short focal
length macro ranging from $250 for a Sigma to $450 for a 60mm Canon or
Nikon, all good lenses. The camera can be a D50 Nikon or a Rebel 300
Canon or any other brand cheap DSLR. It is just pointless to try to do
this kind of work with a P&S. When I had a studio I had a lot of folks
coming in who had tried to photograph their art work and were very
happy to spend $ to have me do it. Most were like the original poster
who were trying to work with point and shoot type equipment.
Tom
Tom
Uni
> What 'trick' am I missing to take a photo of my watercolor paintings?
> Can we 'twist' the digital photo to be square with the camera?
>
> I must be doing something wrong. When I edit my digital photographs of my
> watercolor paintings, I need to crop the photo but I can NEVER get the crop
> edges to be exactly square with the digital camera photograph of the
> painting.
>
> Therefore I always find myself losing a few millimeters of painting so that
> the photograph is square. What am I doing wrong?
>
> Here is how I take the picture.
> a) I put my unmatted 30 inch by 22.5 inch watercolor on a white towel lying
> on the ground
> b) I stand over the painting, sometimes on a step stool, and position the
> Canon PowerShot A95 5MP camera over the center of the painting
> c) I snap the shot using flash & macro focus making sure I am as square as
> possible and taking an extra inch or so of border all around to facilitate
> cropping
>
> Back inside the office, each and every time, when I crop the 2592 by 1944
> pixel digital results using Irvanview 3.98 on Windows XP, I end up with
> edges that are not square at first. I have to lose some of my precious
> painting just to get square edges when I crop.
>
> What am I doing wrong?
A tripod would help. Shooting paintings can be difficult.
> What's the trick to get a photo that is head-on with the painting?
> Is there a way to twist the painting with software so I don't have to crop
> edges and lose painting data?
You can, but you risk adding distortion to the image. IF you must do so,
do it once and only once.
Uni
Carol2
whatever degree you need to using Image>Rotate>Free Rotate. You can
also use the Straighten tool.......located in the drop-down under Deform
(2nd in line on the ToolBar), in PSP8, or.....in PSP10, it is the 6th
tool on the toolbar & shares the space with Perspective tool.
HTH,
Carol2
"maryanne kehoe" <atl...@webtv.net> wrote in message
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Neil Harrington
"2" <nh...@droffats.ten> wrote in message
news:128r36r...@news.supernews.com...
Bullshit. "Get good lenses" and no matter how "good" you still have
distortion, especially barrel distortion at the wide-angle end. Some have
more than others, but no zoom lens is distortion-free throughout its zoom
range.
Anyway, the OP has a Canon A95. She has no other choice of lenses but the
one that came on the camera.
Neil Harrington
"Sally Beacham" <cati...@t.com> wrote in message
news:e6kmt...@news4.newsguy.com...
>
> "maryanne kehoe" <atl...@webtv.net> wrote in message
> news:1lqfc4lyhulse$.1su66j5z1ku9i$.dlg@40tude.net...
>> What 'trick' am I missing to take a photo of my watercolor paintings?
>> Can we 'twist' the digital photo to be square with the camera?
>>
>
> Perspective Correction tool, in PSP 8, 9 and X. Then crop as needed.
I agree she probably does need Perspective Correction, since the way she's
doing it it's unlikely that she's getting the camera lens really
perpendicular to the watercolor. But that doesn't seem to be her complaint.
She asks for a way to "twist" the photo and I take to mean she wants to
correct a slight rotation of the painting in the image, and the Straighten
tool in PSP is what would serve her best for that. I think it's likely she
needs some of both, and maybe a touch of Barrel Distortion Correction too,
maybe not.
Neil Harrington
"Carol2" <wald...@NSprairietech.net> wrote in message
news:128s730...@corp.supernews.com...
> In PSP (vs. 8 - 10) you can, rotate the image to the left/right by
> whatever degree you need to using Image>Rotate>Free Rotate. You can also
> use the Straighten tool.......located in the drop-down under Deform (2nd
> in line on the ToolBar), in PSP8, or.....in PSP10, it is the 6th tool on
> the toolbar & shares the space with Perspective tool.
BTW, how do you like PSP X? I have 8 and 9, and some reviews I've seen of X
indicate that it's not that great an upgrade from 9. That sort of left me
thinking I'd wait until version 11, or XI, whatever Corel decides to call
it. But what's your opinion?
Neil
2
> Bullshit. "Get good lenses" and no matter how "good" you still have
> distortion, especially barrel distortion at the wide-angle end. Some have
> more than others, but no zoom lens is distortion-free throughout its zoom
> range.
Clearly you are unaware of the second generation Biogon.
Xalinai
> What 'trick' am I missing to take a photo of my watercolor paintings?
> Can we 'twist' the digital photo to be square with the camera?
>
> I must be doing something wrong. When I edit my digital photographs
> of my watercolor paintings, I need to crop the photo but I can NEVER
> get the crop edges to be exactly square with the digital camera
> photograph of the painting.
>
> Therefore I always find myself losing a few millimeters of painting
> so that the photograph is square. What am I doing wrong?
>
> Here is how I take the picture.
> a) I put my unmatted 30 inch by 22.5 inch watercolor on a white towel
> lying on the ground
> b) I stand over the painting, sometimes on a step stool, and position
> the Canon PowerShot A95 5MP camera over the center of the painting
> c) I snap the shot using flash & macro focus making sure I am as
> square as possible and taking an extra inch or so of border all
> around to facilitate cropping
>
> Back inside the office, each and every time, when I crop the 2592 by
> 1944 pixel digital results using Irvanview 3.98 on Windows XP, I end
> up with edges that are not square at first. I have to lose some of my
> precious painting just to get square edges when I crop.
>
> What am I doing wrong?
> What's the trick to get a photo that is head-on with the painting?
> Is there a way to twist the painting with software so I don't have to
> crop edges and lose painting data?
As far as you described, all you did is correct:
Camera and image aspect ratio are the same, you centered the camera on
the image an made sure it wasn't tilted in any direction.
Maybe the camera images aren't perfectly linear (common lens problems):
Draw a set of squares 10x10, 15x15, 20x20 on a piece of paper and take
some photos as if they were your image. Then measure height and width.
If you find that the squares are no longer square, you can either use
the factor found to rezize your images (not recommended, you lose
quality) or to compare cameras to find one that does a better job.
You will get better results if you are able to use a longer distance
between image and camera as more distortions occur in the wide angle
setting.
Michael
Neil Harrington
"2" <nh...@droffats.ten> wrote in message
Surely you jest.
J. Clarke
So where does one buy a zoom Biogon? Read what was written. And what is
the rated distortion of the Biogon anyway? Don't say "zero".
2
>
> "2" <nh...@droffats.ten> wrote in message
> news:128sgf1...@news.supernews.com...
>> "Neil Harrington" <n...@home.today> wrote
>> Clearly you are unaware of the second generation Biogon.
>
> Surely you jest.
Well, Neil, ignore the virtues of the Biogon all you wish. It is your loss.
Nathan
perpendicular to the floor?
J. Clarke
Actually the price of the Biogon is _your_ loss. It was a Hell of a lens
when it was new but that was a long, long time ago. The Biogon 2 seems to
just be using the name.
tuckermo
You need to get the top and sides of your picture frame perfectly parallel
to the top and sides of your watercolor, AND you need to have the camera in
a plane parallel to that of the watercolor (not tilted). It's not easy.
If you don't get the top and sides parallel, you can fix it by rotating the
image (but then you will need to crop out some of that border). If the plane
of the camera is not parallel, you can use some sort of perspective
adjustment (more cropping). I'm not familiar enough with PSP to tell you
where it is, but I'm sure it's there.
If you have a lot of these to do, it might be worth it to put your paintings
on a wall and use a tripod to align your camera. An inexpensive one should
be fine.
"maryanne kehoe" <atl...@webtv.net> wrote in message
news:1lqfc4lyhulse$.1su66j5z1ku9i$.dlg@40tude.net...
2
news:e6mgd...@news4.newsguy.com...
>2 wrote:
>> Well, Neil, ignore the virtues of the Biogon all you wish. It is your
>> loss.
>
> Actually the price of the Biogon is _your_ loss. It was a Hell of a lens
> when it was new but that was a long, long time ago. The Biogon 2 seems to
> just be using the name.
Let's be specific. What are you calling "a long time ago"?
Address the 38mm Biogon and 75mm Biogon. The 75mm is discontinued. The 38 is
still in production and the only change in the 38mm is in certain glass
formulas to comply with German environmental standards. Performance is not
visibly effected.
Neil Harrington
"2" <nh...@droffats.ten> wrote in message
I don't question "the virtues of the Biogon," but how many *digital* camera
owners could even use one if they had it?
I couldn't, and I have two digital SLRs, a Nikon and a Minolta. Note that
the OP has a Canon A95 -- what would she do with a Biogon, put it on the
camera with duct tape?
Besides, as J. Clarke pointed out, the Biogon is not a zoom lens, which was
the subject of discussion. I don't doubt that there are a number of
fixed-focal-length lenses (particularly some macro lenses) so nearly
distortion-free that for practical purposes what distortion remains can be
disregarded. But similarly, the typical zoom lens, even a relatively
inexpensive one, is quite distortion-free at least at *some* point in its
zoom range. If it were absolutely essential to have the image
distortion-free at the sensor, it seems to me it would make sense to find
and use that point -- rather than try to find a digital body that you could
put a Zeiss Biogon on. It seems highly unlikely that the latter advice would
be useful to a Canon A95 owner anyway.
J. Clarke
Which means that it has very good performance for 1954. Zeiss doesn't list
a 38, they list a 35 which has quite good distortion, but no better than
some Canon models. But low distortion in a 35mm lens isn't any real trick
these days.
Xiaoding
2 wrote:
> "Ed Ruf" <egruf_...@cox.net> wrote:
>
> > Oh please. Now tell us exactly what P&S with some optical zoom is free
> > from such distortion. Or even which higher end DLSR lens zooms are
> > completely free of it. Not everyone is using perfect primes.
>
> You pay one way or the other. Make your choice. It's still just plain nutz
> to be spending hours fixing a picture that could have been made once,
> properly, in a few minutes.
More like minutes, once you learn to use the tool. Photoshop, 60
seconds, tops, to fix a crooked picture.
maryanne kehoe
> Hang the painting on a wall. Shoot with a tripod. Leave the camera on the
> tripod and check the photos. Adjust until it is correct and leave it there
> for the pictures.
These are large watercolors. I remove the frame and glass to photograph
them. This makes it hard to hang on a wall but I could use masking tape to
tape them to a wall. I would rather not tape my paintings though, for fear
of ruining them when the tape is removed.
maryanne
maryanne kehoe
> PSP has straightening and parallax correction tools. Does your picture
> have more white border at one side then the others.
There is slightly more white on one side than on the other because the
aspect ratio isn't always 100% the same as the LCD display. But I crop all
that out. The problem is that the watercolor paints lap to the edge of the
paper so anything I have to crop that is not 100% square is lost data.
maryanne
maryanne kehoe
> To minimise the effect, start by switching macro mode off. I don't know
> why you're using that.
I thought we were *always* supposed to use macro mode when taking closeups.
I am not sure what a closeup distance is but I'd say I'm about 3 or 4 feet
from the painting when I snap the photograph.
Does that not need macro?
Does macro give more 'distortion'?
maryanne
maryanne kehoe
> How does he have lighting set? Are these unframed oils or watercolors?
These are all watercolors.
I'm not sure what lighting works best but I always take the shots outdoors
because they just seem to come out more realistic that way.
I try to find a cloudy day (which is hard where I live) and I try to take
the shots just as the sun is going down as I find that gives me the most
vivid color on my watercolors.
Still, I find that when I view them in my camera I get one color, on my
monitor I get another color, and in my printer I get yet a third set of
colors, so I'm not sure what I'm doing wrong there.
> Black bg sounds better than white in terms of finished product and
> perhaps in terms of reflecting nothing vs. the white. I suppose grey is
> another option, or even blue or green, then use PS to remove the bg
> entirely.
I use a white plush towel to lay my watercolors on the ground so they don't
get dirty but since I crop out all but the painting, I don't understand how
the background has any effect.
maryanne
maryanne kehoe
> With that size subject I don't know why you're using the macro setting,
> though that probably isn't related to your problem. Also unrelated to that,
> but isn't flash causing you some problems as well?
I was using macro becuase I thought I needed it since I'm a few feet away
from the painting. But I'm glad to not use macro. It doesn't seem to change
things but I didn't do a scientific 1:1 comparison since I hand hold the
camera anyway.
I seem to get the best colors just before the sun sets (I do not know why
but it seems to consistently work out that way) so I try to avoid the flash
but as the sun goes lower I find myself turning the flash on. Sometimes it
works and I get vivid colors but other times the photo is slightly darker
around the edges so I know that's due to the uneven effect of the flash.
Other than that, I don't see how the flash is causing the edges to not be
square with the frame of the picture.
maryanne kehoe
> I presume you are using the LCD display to frame
> your picture. The optical viewfinders in Canon Powershot models show
> only about 85 per cent of what you are actually shooting.
I agree. The optical viewfinder is useless. It shows way more than is
actually in the photograph. I never use that useless optical viewfinder
because of that.
maryanne
maryanne kehoe
> I'd experiment with lighting and white balance settings. It seems to
> me flash might wash out the colors in a watercolor and maybe cause some
> reflection.
I used to get a lot of reflection when I left the glass on the watercolors
but now that I remove them from the frame, I use the flash when the sun
goes down too low (I prefer to do the photos in the late evening which
gives me more even colors for some reason).
When I use the flash, I get about half of the photos looking good - but the
other half are uneven in that the whites of the watercolor are brighter in
the center than at the far edges. It's barely noticeable but I notice it.
maryanne
aussie bongo
rotate the picture slightly in your picture software that you are using
before cropping.???
Floyd L. Davidson
>I try to find a cloudy day (which is hard where I live) and I try to take
>the shots just as the sun is going down as I find that gives me the most
>vivid color on my watercolors.
That works fairly well! Indoors with a large window facing the
right direction can also work well.
If you use flash, research various ways to make it "soft". A
large diffusion surface (such as a white wall or ceiling) can
provide similar results. One advantage is that it can be
repeated exactly every time... same color, same angles,
etc. etc.
>Still, I find that when I view them in my camera I get one color, on my
>monitor I get another color, and in my printer I get yet a third set of
>colors, so I'm not sure what I'm doing wrong there.
That is the bane of doing digital photography in color. Ideally
you would calibrate each device and have a "profile" available
to adjust color for each image. The result would be the same
color and contrast on prints that you see on the screen, and
they would be very close to what you saw with your eyes when you
made the exposure.
However... lacking proper calibration, you can do yourself a
great favor by getting a standard 19% grey card, and
photographing it at the start of your session (and perhaps again
every 15-20 minutes as the light changes if you use natural
lighting). That will give you a reference point that is easier
to adjust for when processing the images later.
One way to do that is to simply place the grey card behind each
painting, with a little bit showing around the edge... and then
don't frame so close that it cannot be seen. You have to crop
the image with software every time, but that is probably
necessary anyway and you get a color correction point included
in every image.
>I use a white plush towel to lay my watercolors on the ground so they don't
>get dirty but since I crop out all but the painting, I don't understand how
>the background has any effect.
The way I've done it is to use an easel for the paintings and a
tripod for the camera. I try to get things relatively square,
but quite honestly don't fuss about it much, because they all
require adjustment anyway. I use software to make corrections
as necessary (using GIMP, which is probably no better or worse
than PhotoShop or other software).
In my case the background is a white wall, and I use that for
color correction, instead of a grey card.
As far as macro mode goes... use it only if you can't get full
frame images without it. (I'm not familiar with your camera, so
I'm not sure what "macro mode" does exactly.)
I use a Nikon DSLR, and have tried a variety of different lenses
(macro lenses, zoom lenses, Nikon lenses, Vivitar lenses,
Russian made lenses, etc. etc) just for fun. The lense
generally doesn't make a lot of difference in the end. But to
make it all a lot easier (in my case the paintings come in a
huge variety of sizes as this artist tends to grab whatever is
available and paint on it as the mood hits), one good zoom lens
avoids a lot of moving the camera tripod back and forth the get
the right size. But as others have noted, zoom lenses will tend
to have different distortions at the ends of the zoom range, so
the results do vary. If you don't have a camera with
interchangeable lenses, you can either choose to correct the
different distortions using software, or find the "sweet spot"
for that lense and move the camera to adjust framing as needed.
--
Floyd L. Davidson <http://www.apaflo.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) fl...@apaflo.com
Bart van der Wolf
SNIP
> These are large watercolors. I remove the frame and glass to
> photograph them. This makes it hard to hang on a wall but I
> could use masking tape to tape them to a wall. I would rather
> not tape my paintings though, for fear of ruining them when
> the tape is removed.
If they're not too big, you could perhaps lay them on the floor?
Bart
Neil Harrington
> On Mon, 12 Jun 2006 09:40:10 -0400, Neil Harrington wrote:
>> With that size subject I don't know why you're using the macro setting,
>> though that probably isn't related to your problem. Also unrelated to
>> that,
>> but isn't flash causing you some problems as well?
>
> I was using macro becuase I thought I needed it since I'm a few feet away
> from the painting.
Mostly macro is used when *really* close to the subject, a few inches or
maybe a foot or so, when it's necessary in order to get the camera to focus
at such short distances. You say you're shooting at 3 or 4 feet, which
sounds about right for the way you're doing it, and since the Canon A95 will
easily focus at such distances without going into macro mode there isn't
much point to it.
> But I'm glad to not use macro. It doesn't seem to change
> things but I didn't do a scientific 1:1 comparison since I hand hold the
> camera anyway.
Some cameras do change things in macro mode, e.g. some Minolta cameras in
macro mode fix the focal length at a point which eliminates barrel or
pincushion distortion. But in the case of the Canon A95, all it seems to do
is allow closer focusing.
>
> I seem to get the best colors just before the sun sets (I do not know why
> but it seems to consistently work out that way) so I try to avoid the
> flash
> but as the sun goes lower I find myself turning the flash on. Sometimes it
> works and I get vivid colors but other times the photo is slightly darker
> around the edges so I know that's due to the uneven effect of the flash.
>
> Other than that, I don't see how the flash is causing the edges to not be
> square with the frame of the picture.
No, the flash wouldn't affect that. What I meant by possible problems was
reflection from the subject and/or uneven lighting of the subject.
As for getting vivid colors, that (along with many other things) is
something you can control to a large degree with software. I'd suggest you
think about getting Paint Shop Pro, which is a very powerful but relatively
easy to use image editing program. You should be able to find version 8 or 9
fairly cheap on eBay, or perhaps from some discount sellers.
Bruce Hoult
maryanne kehoe <atl...@webtv.net> wrote:
All lenses have distortion, sometimes quite complex. Even the best ones
usually have a little pure pincushion/barrel distortion (which can be
removed in Photoshop CS) at some focal lengths and are neutral at
others. I woudln't expect a P&S camera with a 3:1 zoom lens to be
especially lacking in distortion, and in particular it will almost
certainly have barrel distortion when zoomed wide.
It seems to me that you're probably far too close and needing to use too
wide an angle. It would probably be much better to be 5m - 10m from the
painting and using a much longer lens setting. At least try to get far
enough away that you can zoom the lens most of the way in.
--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------
J. Clarke
If it's entirely outside the frame it should have no effect other than
possibly some lens flare, if any of it is in the frame it will affect
metering.
Suggestion--you might want to consider making up a vacuum table, which can
be as simple as a piece of hardware-store perfboard built on a box frame
and powered by a vacuum cleaner, or can get fairly elaborate. Should hold
the painting flatter, and you can mount it vertically, which may make it
easier to align everything.
> maryanne
J. Clarke
> On Mon, 12 Jun 2006 08:41:20 +0100, Derek Fountain wrote:
>> To minimise the effect, start by switching macro mode off. I don't know
>> why you're using that.
>
> I thought we were *always* supposed to use macro mode when taking
> closeups. I am not sure what a closeup distance is but I'd say I'm about 3
> or 4 feet from the painting when I snap the photograph.
>
> Does that not need macro?
In general, no unless you are using a fairly long focal length lens.
> Does macro give more 'distortion'?
It may provide some image processing that if the lens is not focussed in
close makes things worse instead of better.
John McWilliams
Well, that's where this all started!
--
john mcwilliams
2
> Which means that it has very good performance for 1954. Zeiss doesn't
> list
> a 38, they list a 35 which has quite good distortion, but no better than
> some Canon models. But low distortion in a 35mm lens isn't any real trick
> these days.
Dating a lens design doesn't necessarily measure against its quality.
You might appreciate learning the facts regarding the Biogon design. It was
so well designed from the outset that it required only one redesign to be as
good as it could get. In fact, when lens designers finally had affordable
computers they thought, "Wow! We think the Biogon is good now. Let's pour
the design through the computer and make it perfect." They could not. It
was already perfect.
If we are sticking to (nominal) 35mm format, then maybe you are right.
I was speaking of the 38mm Biogon. And if you like, a certain 75mm and 76mm.
Bart van der Wolf
"2" <nh...@droffats.ten> wrote in message
SNIP
> It was already perfect.
*Nothing* is perfect.
It may be as good as current technology allows, IOW almost perfect,
but the future may present the opportunity of improving even that tiny
bit of aberration that is virtually unnoticeable for the use it was
originally designed for.
Besides any (especially multi-component) piece of hardware is subject
to manufacturing tolerances, however small they may be, on average.
It's like infinity, it will never be reached, not even by accident.
Bart
J. Clarke
> "J. Clarke" <jclarke...@snet.net.invalid> wrote
>
>> Which means that it has very good performance for 1954. Zeiss doesn't
>> list
>> a 38, they list a 35 which has quite good distortion, but no better than
>> some Canon models. But low distortion in a 35mm lens isn't any real
>> trick these days.
>
> Dating a lens design doesn't necessarily measure against its quality.
No, but it's unusual that first lens in a class is also the best that will
ever be made in that class.
> You might appreciate learning the facts regarding the Biogon design. It
> was so well designed from the outset that it required only one redesign to
> be as
> good as it could get.
You mean it hits the theoretical limits for a lens of that aperture and
focal length in every regard?
> In fact, when lens designers finally had affordable
> computers they thought, "Wow! We think the Biogon is good now. Let's pour
> the design through the computer and make it perfect." They could not. It
> was already perfect.
If it was already perfect then why would they try to improve it?
> If we are sticking to (nominal) 35mm format, then maybe you are right.
>
> I was speaking of the 38mm Biogon. And if you like, a certain 75mm and
> 76mm.
Would you care to share test results on that lens? If it is such a paragon
of perfection I would think that the tests to prove it would be posted all
over Creation.
2
>> In fact, when lens designers finally had affordable
>> computers they thought, "Wow! We think the Biogon is good now. Let's pour
>> the design through the computer and make it perfect." They could not. It
>> was already perfect.
>
> If it was already perfect then why would they try to improve it?
It's human nature.
Before computer ray-tracing, all design was all done by hand and mind. A
person used all his knowledge of optics, glass compounds, and assembled the
cross-section on paper, then hand ray-traced the design. It could take years
to do one tracing.
When computers (especially the mini-computer, for example the PDP) became
affordable, everyone switched to computers. It was natural for them to apply
the technology to favorites in order to try tweaks, variations.
>> If we are sticking to (nominal) 35mm format, then maybe you are right.
>>
>> I was speaking of the 38mm Biogon. And if you like, a certain 75mm and
>> 76mm.
>
> Would you care to share test results on that lens? If it is such a
> paragon
> of perfection I would think that the tests to prove it would be posted all
> over Creation.
It is all over creation. Very well known to lens experts, designers.
2
news:44905b19$0$31639$e4fe...@news.xs4all.nl...
>
> "2" <nh...@droffats.ten> wrote in message
> news:1290g02...@news.supernews.com...
> SNIP
>> It was already perfect.
>
> *Nothing* is perfect.
>
> It may be as good as current technology allows, IOW almost perfect, but
> the future may present the opportunity of improving even that tiny bit of
> aberration that is virtually unnoticeable for the use it was originally
> designed for.
You are nitpicking. Of course, we can only test what we have at the moment.
It is as good as current technology can make it. That doesn't mean we won't
keep trying to make better lenses.
J. Clarke
> "J. Clarke" <jclarke...@snet.net.invalid> wrote:
>
>>> In fact, when lens designers finally had affordable
>>> computers they thought, "Wow! We think the Biogon is good now. Let's
>>> pour
>>> the design through the computer and make it perfect." They could not.
>>> It was already perfect.
>>
>> If it was already perfect then why would they try to improve it?
>
> It's human nature.
>
> Before computer ray-tracing, all design was all done by hand and mind. A
> person used all his knowledge of optics, glass compounds, and assembled
> the cross-section on paper, then hand ray-traced the design. It could take
> years to do one tracing.
>
> When computers (especially the mini-computer, for example the PDP) became
> affordable, everyone switched to computers. It was natural for them to
> apply the technology to favorites in order to try tweaks, variations.
Which misses the point. You have asserted that it was perfect. If it was
perfect then what was the nature of the improvement they sought to make?
>>> If we are sticking to (nominal) 35mm format, then maybe you are right.
>>>
>>> I was speaking of the 38mm Biogon. And if you like, a certain 75mm and
>>> 76mm.
>>
>> Would you care to share test results on that lens? If it is such a
>> paragon
>> of perfection I would think that the tests to prove it would be posted
>> all over Creation.
>
> It is all over creation. Very well known to lens experts, designers.
--
J. Clarke
As good as that particular design concept allows or as good as it is
possible in theory for a lens of that aperture to be in all regards or
what? Define "good".
And please provide a source for your assertions concerning its perfection.
2
> Which misses the point. You have asserted that it was perfect. If it was
> perfect then what was the nature of the improvement they sought to make?
They found that the original design was most excellent, and it endured
through revolutions in glass technology so that it became even better. Is
that too much for your mind to comprehend?
Get a grip on your problem, Clark, or be stuck in a place from which you
cannot grow.
J. Clarke
I'm not the one who is holding up a 1954 design as the paragon of optical
perfection with no evidence whatsoever other than that that he pulled out
of his bunghole.
David J. Littleboy
"J. Clarke" <jclarke...@snet.net.invalid> wrote:
>2 wrote:
>> "J. Clarke" <jclarke...@snet.net.invalid> :
>>
>>> Which misses the point. You have asserted that it was perfect. If it
>>> was perfect then what was the nature of the improvement they sought to
>>> make?
>>
>> They found that the original design was most excellent, and it endured
>> through revolutions in glass technology so that it became even better. Is
>> that too much for your mind to comprehend?
>>
>> Get a grip on your problem, Clark, or be stuck in a place from which you
>> cannot grow.
>
> I'm not the one who is holding up a 1954 design as the paragon of optical
> perfection with no evidence whatsoever other than that that he pulled out
> of his bunghole.
He certainly makes it sound as though he's blowing smoke, but the Biogon
design is widely respected. Not only the Zeiss 38mm, but the 65mm lens in
the Fuji GSW690 and the 43, 50, and 65mm Mamiya 7 lenses are some of the
best lenses in medium format. Light falloff is more of a problem than he
likes to admit, though.
FWIW, the design actually got _worse_ in its latest incarnation; the
inability to use leaded glass forced Zeiss to accept some compromises in the
latest version of the 38mm lens. It's still a lot better than the (also
Zeiss) 40mm Distagon (a retrofocus design), which was recently redesigned to
improve resolution at the cost of increased distortion.
These are all (except for the Mamiya and Fuji 65mm lenses) seriously
expensive lenses. Even used, the Mamiya 43 and 50mm lenses (for 6x7) are
around US$1400, and the Zeiss 38mm lens (in a body that's not much more than
a box) is around US$2500. In my experience, the 65mm Mamiya lens easily
outresolves the 5D, whatever lens you put on the 5D. But if you want to take
pictures, a 5D with a 17-40 is a lot more practical (and goes a lot wider)
than a set of Mamiya Biogons on a Mamiya 7, and you won't notice the
difference at 13x19 (I have test prints that demonstrate this clearly).
Here is a page of test results that covers some of these lenses (and a lot
of others).
http://www.hevanet.com/cperez/MF_testing.html
David J. Littleboy
Tokyo, Japan
Floyd L. Davidson
>2 wrote:
>> "J. Clarke" <jclarke...@snet.net.invalid> :
>>
>>> Which misses the point. You have asserted that it was perfect. If it
>>> was perfect then what was the nature of the improvement they sought to
>>> make?
>>
>> They found that the original design was most excellent, and it endured
>> through revolutions in glass technology so that it became even better. Is
>> that too much for your mind to comprehend?
To be more specific, the original Biogon design was in 1934,
*before* such things as optical coating. The 1954 design of
course suffered from various temporal restrictions too, mostly
in the manufacturing process, that also no longer apply. Hence,
yes there have been "improvements" as far as the actual product
goes. The basic design, however, is the same, with of course
adjustements made for the materials available.
"Contrast and image brilliance are better today, thanks to
the Carl Zeiss T* multi-layer anti-reflex coating. Color
rendition is better today as a result of optical glass types
with improved control of color shift. Today's Biogon lenses
provide more uniform performance from each unit produced, as
a result of the advanced mechanics and a far more rigid
shutter."
http://www.hasselbladusa.com/gallery/forumArticle.asp?secId=1074&itemId=3398
>I'm not the one who is holding up a 1954 design as the paragon of optical
>perfection with no evidence whatsoever other than that that he pulled out
>of his bunghole.
In this case the supporting evidence is fairly good for what he
has said. It comes from Hasselblad, which may not be exactly an
"independant" source, but...
"Without any restrictions regarding glass material, cost,
bulk, and weight of a 38mm lens for medium format, could a
design clearly better than the present Biogon 4.5/38mm design
be achieved?
We have done a great deal of research on these issues, since
Hasselblad is always very interested in top performance
products and components. We actually designed alternative
versions for the Biogon 38 and simulated them in our
computers. What we found is this: our computer simulations
showed that at approximately twice the cost, with a bigger
size, and using optical materials which are difficult to
polish and to coat, and which do compromise the thermal
stability of the optical performance, we could achieve slight
improvements. These improvements, however, are incremental
only, and are very likely to not show up at all on actual
film. The Biogon 38mm version used in the Hasselblad 905SWC
already pushes the best color films to their very limits and
beyond. Therefore, both Hasselblad and Carl Zeiss decided
not to saddle SWC users with a doubled price tag for the
lens."
http://www.hasselbladusa.com/gallery/forumArticle.asp?secId=1074&itemId=3398
Granted they didn't say it was "perfect" as is, they just said it
is so close that nobody will pay for the cost of improving it.
J. Clarke
They're also trying to sell you something. According to Leica Leica's
lenses are perfection, according to Canon Canon's lenses are perfection,
according to Nikon, Nikon's lenses are perfection, according to whoever
makes cardboard disposables the lenses on cardboard disposables are
perfection. Have you ever known any camera manufacturer to say that any of
their lenses were _not_ the greatest on Earth?
J. Clarke
>
> "J. Clarke" <jclarke...@snet.net.invalid> wrote:
>>2 wrote:
>>> "J. Clarke" <jclarke...@snet.net.invalid> :
>>>
>>>> Which misses the point. You have asserted that it was perfect. If it
>>>> was perfect then what was the nature of the improvement they sought to
>>>> make?
>>>
>>> They found that the original design was most excellent, and it endured
>>> through revolutions in glass technology so that it became even better.
>>> Is
>>> that too much for your mind to comprehend?
>>>
>>> Get a grip on your problem, Clark, or be stuck in a place from which you
>>> cannot grow.
>>
>> I'm not the one who is holding up a 1954 design as the paragon of optical
>> perfection with no evidence whatsoever other than that that he pulled out
>> of his bunghole.
>
> He certainly makes it sound as though he's blowing smoke, but the Biogon
> design is widely respected. Not only the Zeiss 38mm, but the 65mm lens in
> the Fuji GSW690 and the 43, 50, and 65mm Mamiya 7 lenses are some of the
> best lenses in medium format. Light falloff is more of a problem than he
> likes to admit, though.
I'm sure it's a good lens, but I still doubt that it achieves perfection.
> FWIW, the design actually got _worse_ in its latest incarnation; the
> inability to use leaded glass forced Zeiss to accept some compromises in
> the latest version of the 38mm lens. It's still a lot better than the
> (also Zeiss) 40mm Distagon (a retrofocus design), which was recently
> redesigned to improve resolution at the cost of increased distortion.
>
> These are all (except for the Mamiya and Fuji 65mm lenses) seriously
> expensive lenses. Even used, the Mamiya 43 and 50mm lenses (for 6x7) are
> around US$1400, and the Zeiss 38mm lens (in a body that's not much more
> than a box) is around US$2500. In my experience, the 65mm Mamiya lens
> easily outresolves the 5D, whatever lens you put on the 5D. But if you
> want to take
> pictures, a 5D with a 17-40 is a lot more practical (and goes a lot
> wider) than a set of Mamiya Biogons on a Mamiya 7, and you won't notice
> the difference at 13x19 (I have test prints that demonstrate this
> clearly).
The issue the OP is dealing with is distortion, not resolution.
> Here is a page of test results that covers some of these lenses (and a lot
> of others).
>
> http://www.hevanet.com/cperez/MF_testing.html
Which has absolutely no information about distortion.
Bart van der Wolf
"David J. Littleboy" <dav...@gol.com> wrote in message
news:e6qlb7$g9o$1...@nnrp.gol.com...
SNIP
> He certainly makes it sound as though he's blowing smoke, but the
> Biogon design is widely respected.
Correct, but so is e.g. the Super Angulon from Schneider, and others.
They all are very good for their intended use, and are examples that
set a target for most others, but perfect they aren't. So blowing
smoke it is.
Bart
Bart van der Wolf
"Floyd L. Davidson" <fl...@apaflo.com> wrote in message
news:87ac8fx...@apaflo.com...
SNIP
> Granted they didn't say it was "perfect" as is, they just said it
> is so close that nobody will pay for the cost of improving it.
Exactly, which is a much more realistic statement. Besides, I haven't
seen it mentioned (maybe my fault) that it requires a special camera
to accomodate the lens since it needs to be placed in very close
proximity to the sensor/film. That by itself will guarantee vignetting
and light fall-off issues.
Bart
ASAAR
> When I use the flash, I get about half of the photos looking good - but the
> other half are uneven in that the whites of the watercolor are brighter in
> the center than at the far edges. It's barely noticeable but I notice it.
That's as it should be, since the flash is so close to the
painting that the distance from flash to the center of the painting
is noticeably less than the distance from the flash to the edge of
the painting. You could minimize the difference in brightness by
either moving the A95 farther away from the painting (and using a
greater focal length) or by using a different light source. If the
A95 had a hot shoe or PC connector, an external flash could be
either positioned farther away, or the flash head could be swiveled
so that the light path could be greatly increased by bouncing the
light from the ceiling or a wall. A "smart" external flash that's
triggered by the main flash (not by any of the preflashes) could
also help (you might want to block most of the light emitted by the
A95's internal flash), but the best inexpensive solution might be to
use a couple of cheap halogen or fluorescent work lights to provide
even illumination, along with an appropriate white balance.
2
> Correct, but so is e.g. the Super Angulon from Schneider, and others. They
> all are very good for their intended use, and are examples that set a
> target for most others, but perfect they aren't. So blowing smoke it is.
Good gosh, Man! The Super Angulon is NOT a Biogon design!
2
news:449142ec$0$31637$e4fe...@news.xs4all.nl...
> Exactly, which is a much more realistic statement. Besides, I haven't seen
> it mentioned (maybe my fault) that it requires a special camera to
> accomodate the lens since it needs to be placed in very close proximity to
> the sensor/film. That by itself will guarantee vignetting and light
> fall-off issues.
Yes, the rear lens element does sit close to the film or sensor, however it
does not require a special camera. It is very much at home on a rangefinder.
J. Clarke
So on what digital camera are you using it?
J. Clarke
Who claimed that it was?
2
>> Yes, the rear lens element does sit close to the film or sensor, however
>> it does not require a special camera. It is very much at home on a
>> rangefinder.
>
> So on what digital camera are you using it?
The Leica digital-M, of course. :) But that's a couple months out.
Okay, there is no digital rangefinder for a Biogon right now. However, one
can use the digital back on the SWC (aka: 905SWC).
Someday digital will catch up to film technology cameras, except for LF of
course.
J. Clarke
So your advice to this person is that the only viable solution to her
problem is a digital back on a Hasselblad?
Seems like overkill to me.
2
> So your advice to this person is that the only viable solution to her
> problem is a digital back on a Hasselblad?
I swear you are trying to turn this into a flame war. It won't happen.
Read back. She knows what she has to do using her current setup.
ASAAR
He is quite skilled at misunderstanding and leaping to absurd
conclusions in order to avoid admitting error or coming to an
amicable agreement. But look on the bright side. In another recent
rpd thread:
>> On Sun, 11 Jun 2006 06:52:27 -0400, J. Effing Clarke wrote:
>>
>>>> to position the lens's focus point? If you want to define the
>>>> subject that way, go ahead. But it's quite a stupid definition, one
>>>> that nobody in their right mind would every use, except perhaps as
>>>> empty argument fodder.
>>>
>>> Oh, for Christ's sake, GIVE IT AN EFFING REST.
>>
>> My very point, but you chose to not give it an effing rest.
>
> <plonk>
With any luck at all, J. Effing Clarke will tire of his wearysome
game and grant you a plonk boon too. <g>
Floyd L. Davidson
>"J. Clarke" <jclarke...@snet.net.invalid> wrote
>> So your advice to this person is that the only viable solution to her
>> problem is a digital back on a Hasselblad?
>
>I swear you are trying to turn this into a flame war. It won't happen.
He has an *extremely* pertinent point.
>Read back. She knows what she has to do using her current setup.
Read back, this discussion of the Biogon lense design has
absolutely *no* relevance to the OP's circumstance. It cannot
be held up as *any* sort of a solution, short of... a digital
back on a Hasselblad????
He could have worded the significance a lot less polite than he
did... :-)
Bart van der Wolf
"2" <nh...@droffats.ten> wrote in message
SNIP
> Yes, the rear lens element does sit close to the film or sensor,
> however it does not require a special camera. It is very much at
> home on a rangefinder.
View cameras need special bellows to allow the close proximity,
Hasselblad had to create the SWC to accomodate the fixed lens, and
rangefinders with exchangable lenses aren't exactly what I would call
common these days. I also hope it comes with a center spot filter to
combat vignetting.
Bart
2
> Read back, this discussion of the Biogon lense design has
> absolutely *no* relevance to the OP's circumstance.
So shoot me for topic drift.
> He could have worded the significance a lot less polite than he
> did... :-)
So what? He should be congratulated for not beating his wife, too?
2
>
> "2" <nh...@droffats.ten> wrote in message
> news:1292p8r...@news.supernews.com...
> SNIP
>> Yes, the rear lens element does sit close to the film or sensor, however
>> it does not require a special camera. It is very much at home on a
>> rangefinder.
>
> View cameras need special bellows to allow the close proximity,
No they do not. For gosh sake, I use two different LF biogons and the
conventional 75mm works on both the Linhof Technika and Linhof Color and the
Sinar without special bellows or special focusing devices. I'm sure it works
on plenty of others, too.
The unconventional 76mm Super Biogon works on the Sinar, standard bellows.
> Hasselblad had to create the SWC to accomodate the fixed lens, and
> rangefinders with exchangable lenses aren't exactly what I would call
> common these days.
How uncommon is a Leica? Linhof Super Technika? Horseman? Contax? Good gosh,
man, they are made today. The digital Leica M is due to be out in a couple
months.
> I also hope it comes with a center spot filter to combat vignetting.
You don't have a single clue of reality.
The 38mm, 75mm and 76mm Biogons have very gentle fall-off. Very, very few
people use a center filter with them. Super-Angulons need LOTS of help in
that regard, but Biogons have gentle falloff within their given area of
coverage.
J. Clarke
> What 'trick' am I missing to take a photo of my watercolor paintings?
> Can we 'twist' the digital photo to be square with the camera?
>
> I must be doing something wrong. When I edit my digital photographs of my
> watercolor paintings, I need to crop the photo but I can NEVER get the
> crop edges to be exactly square with the digital camera photograph of the
> painting.
>
> Therefore I always find myself losing a few millimeters of painting so
> that the photograph is square. What am I doing wrong?
>
> Here is how I take the picture.
> a) I put my unmatted 30 inch by 22.5 inch watercolor on a white towel
> lying on the ground
> b) I stand over the painting, sometimes on a step stool, and position the
> Canon PowerShot A95 5MP camera over the center of the painting
> c) I snap the shot using flash & macro focus making sure I am as square as
> possible and taking an extra inch or so of border all around to facilitate
> cropping
>
> Back inside the office, each and every time, when I crop the 2592 by 1944
> pixel digital results using Irvanview 3.98 on Windows XP, I end up with
> edges that are not square at first. I have to lose some of my precious
> painting just to get square edges when I crop.
>
> What am I doing wrong?
> What's the trick to get a photo that is head-on with the painting?
> Is there a way to twist the painting with software so I don't have to crop
> edges and lose painting data?
The discussion got way off topic with all the Biogon crap to which I
apologize for contributing. If you are Donald Trump, Martha Stewart, or
someone else with a like or similar income then rush right out and get a
Hasselblad Super Wide C with a 38mm Biogon and a digital back. If you are
a normal person then there are some other alternatives.
Basically your choices are to fix it in your setup or fix it in software.
If you have a copy of Photoshop already then you might find the discussion
at <http://www.larry-bolch.com/perspective/photoshop.htm> to be of
interest. Takes you step by step through correcting both perspective and
barrel distortion. This will cost you some sharpness, whether that is an
issue depends on your circumstances.
Similar procedures can be used with many other image editing programs. I
believe that other posts have suggested software purpose designed for this
task as well. If you're preparing images for the Web this should be quite
adequate.
The alternative is to fix it in the setup and the camera--you'll need to
align the camera with the painting and use a lens with very low distortion
to do this.
Before you spend a lot of money on a camera, you might want to make up a
test target that is just a square grid on a piece of paper the same size as
your paintings and try shooting it with different zoom settings until you
find the one that gives you the lowest distortion and see if that is good
enough for your purpose.
If it turns out not to be the case, then you might want to take a look at
<http://www.photozone.de/8Reviews/index.html>, where you'll find distortion
tests on a number of lenses, mostly for the Canon system but some Nikon and
third-party as well. I think that the Canon Digital Rebel XT with the
10-22 f/3.5-4.5 lens might be a nice setup for you--that lens has a
low-distortion sweet spot at about 14mm that would give you a working
distance of about 18 inches--no standing on a stool, but lighting might be
a problem. If that's too close the 17-85 has one at about 24mm that would
give you a working distance of about 3 feet. If you can work 7 feet from
the subject then the 60mm macro would be a good bet.
customla...@gmail.com
Large Format, a digital printing company that specializes in artwork
reproductions.
The problem you are experiencing is an effect caused by the curvature
of the lens of the camera, and even though is accurate enough to
project a 'relatively square' image onto the internal sensor, it is not
perfect. (as you are experiencing)
There is a very simple solution to this: In Photoshop, select the
entire image before cropping. Go to Filter / distort / lens correction.
A 'remove distortion' slider at the top right of the effect box is what
you're looking for.
Hope this solves all your problems!
Pat
www.customlargeformat.com
Neil Harrington
"2" <nh...@droffats.ten> wrote in message
Not through any extended discussion of Biogons, she doesn't.
Again: the lady has a Canon A95, an under-$300 camera. How likely is it that
any A95 owner is going to spring for any camera body that takes a Biogon,
plus the lens itself?
2
"Neil Harrington" <n...@home.today> wrote:
> Not through any extended discussion of Biogons, she doesn't.
So shoot me for topic drift. But shoot the other(s), too.
Floyd L. Davidson
>"Floyd L. Davidson" <fl...@apaflo.com> wrote
>
>> Read back, this discussion of the Biogon lense design has
>> absolutely *no* relevance to the OP's circumstance.
>
>So shoot me for topic drift.
Topic drift is fine; like shit, it just happens.
But this and your previous article are purposely non-responsive.
You ignore the meaning of what others say, and act as if they
had said something they didn't.
>> He could have worded the significance a lot less polite than he
>> did... :-)
>
>So what? He should be congratulated for not beating his wife, too?
The point was, though obviously too subtle, that he *should*
have been less polite, because you didn't deserve treatment that
nice.
2
"Floyd L. Davidson" <fl...@apaflo.com> wrote in message
news:87zmgdu...@apaflo.com...
> "2" <nh...@droffats.ten> wrote:
>>So shoot me for topic drift.
>
> Topic drift is fine; like shit, it just happens.
> The point was, though obviously too subtle, that he *should*
> have been less polite, because you didn't deserve treatment that
> nice.
I deserve bad treatment because I was right?
J. Clarke
No, because you're an obnoxious pest who doesn't even try to back up what he
says with anything other than somebody's sales pitch.
2
news:e6tvg...@news2.newsguy.com...
>> I deserve bad treatment because I was right?
>
> No, because you're an obnoxious pest who doesn't even try to back up what
> he
> says with anything other than somebody's sales pitch.
So you ARE trying to start a flame thread. Silly you.
Look, I was writing about equipment I know and use.
Bart van der Wolf
"2" <nh...@droffats.ten> wrote in message
> "Bart van der Wolf" <bvd...@no.spam> wrote in message
> news:4491b33b$0$31656$e4fe...@news.xs4all.nl...
>> View cameras need special bellows to allow the close proximity,
>
> No they do not.
Here's a picture of the one for the Linhof M 679cc (bottom right):
<http://www.linhof.com/english/kameras/m679/m679cc.html#>
or for another model
<http://www.linhof.com/english/kameras/technikardan/kameraset_69.html>
TK wide-angle bellows 23, Article no. 002724
or for another model
<http://www.linhof.com/english/kameras/kardansystem/kameraset_e.html>
Wide-angle bellows 45, Article no.: 002584
I guess they're a waste of money then, ... or do you utilize a view
camera
without rise/fall/swing/tilt/shift?
> For gosh sake, I use two different LF biogons and the conventional
> 75mm works on both the Linhof Technika and Linhof Color
The Technica is a rangefinder, not a Viewfinder camera. I don't recall
a
Color model so I can't comment on that one.
> and the Sinar without special bellows or special focusing devices.
> I'm sure it works on plenty of others, too.
You are suggesting full movements can be used with the Sinar standard
multipurpose bellows with infinity focus? Pray tell how much, because
that'll save a few people from having to buy:
<http://www.sinarcameras.com/file_uploads/bibliothek/k_92_Brochures/285_0_prka_balgen_e.pdf
>
Page 2 shows you the Wide angle bellows that are needed for relatively
short
focal lengths, like the 75mm.
SNIP
>> Hasselblad had to create the SWC to accomodate the fixed lens, and
>> rangefinders with exchangable lenses aren't exactly what I would
>> call common these days.
>
> How uncommon is a Leica? Linhof Super Technika? Horseman? Contax?
Exchangeable lens rangefinders compared to SLR's? Just guessing,
1:100000?
Do you have precise numbers????
Hint, Canon alone just hit the 30 million EF lenses (that's the
successor of
their prior lenses and matching bodies) barrier last January, 10
million of
which have been produced the last five years. Even with an average of
say 2
original Canon lenses per body, it should give you an idea. And then
there
are the other manufacturers like Nikon, Minolta, etc., etc.
SNIP
>> I also hope it comes with a center spot filter to combat
>> vignetting.
>
> You don't have a single clue of reality.
>
> The 38mm, 75mm and 76mm Biogons have very gentle fall-off.
You mean like the Hasselblad image at:
<http://www.hasselblad.co.uk/products/level3.asp?secId=614&itemId=394>
?
> Very, very few people use a center filter with them.
So? And besides, how do you know, you know them all?
> Super-Angulons need LOTS of help in that regard,
In which case it should be simple for you to come up with an example
of an
equal size image circle for a given focal length? I'm looking forward
to
that, but I won't hold my breath.
> but Biogons have gentle falloff within their given area of coverage.
Yes, their image circle is considered rather small by some
(http://www.kenrockwell.com/tech/zeiss75biogon.htm) that's true, but
unfortunately they don't escape the laws of physics, so falloff is
unavoidable, especially when the exit pupil is so close to the film
plane.
Geez, if all *spin* was as transparent as yours, there wouldn't be
many
politicians.
Bart
J. Clarke
Then test it and get back to us with the numbers.
2
>> Look, I was writing about equipment I know and use.
>
> Then test it and get back to us with the numbers.
Gee, John, why should I "test it" for your (unstated) metrics when it works
very well for me?
I USE the 75mm Super Angulon right next to the 75 and 76mm Biogons. I KNOW
how they behave. I also USE the 38mm Biogon. I HAVE USED many wide lenses
for 35mm. See? I don't live in some kind of net-fog, but in reality. You
might want to try it sometime.
Besides, you can go to any number of sites which do 'tests'. Do your own
research. I owe you nothing for the nothing you have given to this thread.
I am not an optical bench-racer-bullshitter who doesn't work.
Now, I am off to work.