Dark seams
panog...@gmail.com
I am facing an unusual problem I cannot solve.
It's about a partial panorama made of 4 rows and 52 columns from
Nikkor 180mm.
Of course shot in manual mode.
The upper row, mainly sky and foggy mountains, shows horrible dark
seams.
At first sight I thought it was a bad vignetting setting from Capture
NX. So I test with different settings
but nothing changed, the crop I provide below is my best result... Ok
It was far for a crystal day for landscape shoot, but I had to record
the very unsusual snowy coat we had in the area.
My first test was made with PTGui 8.3.6 then I update to a PRO version
hoping to improve quality.
I tried to blend an output with Enblend 4.0 without improvement.
In the Exposure/HDR tab I tried checking "Exposure correction" button
without improvemnt.
What else could I do in this tab ?
http://www.animatif.com/temp/stitch/PTgui_exposure.png
Here's a crop of raw #1 output from PTGui Pro 8.6.3 (only modified jpg
level) :
http://www.animatif.com/temp/stitch/crop_sky.jpg
So what could be the problem here and what could I do to improve my
panorama ?
I can provide some of the original Tiff files if neded.
Thank you for your help.
Cheers,
G.
Joergen Geerds
from not using a UV filter, or using a bad UV filter? I had purple
spots in some of my very early day panos, and it was clear they came
from UV.
it might be helpful if you can post a screenshot of one the RAW shots.
that might help also.
joergen
On Jan 27, 9:48 am, "panogra...@gmail.com" <panogra...@gmail.com>
wrote:
> Hi,
>
> I am facing an unusual problem I cannot solve.
> It's about a partial panorama made of 4 rows and 52 columns from
> Nikkor 180mm.
> Of course shot in manual mode.
> The upper row, mainly sky and foggy mountains, shows horrible dark
> seams.
>
> At first sight I thought it was a bad vignetting setting from Capture
> NX. So I test with different settings
> but nothing changed, the crop I provide below is my best result... Ok
> It was far for a crystal day for landscape shoot, but I had to record
> the very unsusual snowy coat we had in the area.
>
> My first test was made with PTGui 8.3.6 then I update to a PRO version
> hoping to improve quality.
> I tried to blend an output with Enblend 4.0 without improvement.
>
> In the Exposure/HDR tab I tried checking "Exposure correction" button
> without improvemnt.
> What else could I do in this tab ?http://www.animatif.com/temp/stitch/PTgui_exposure.png
Ken Warner
It was a really tight seam -- really small overlap on a snow field so
the there was a lot of white.
At the seam, the left side was slightly magenta, the right side slightly
cyan and there was a noticeable line on the seam. I reshot with more
overlap and it the seam cleared up a bit.
I didn't want to say anything because I figured it was something I was
doing wrong. I think I can dredge up a sample image if anyone is interested.
Hans
vignetting but that could also be contributing.
Most shutters are travelling on the short side and if they do not do
that even the exposure will not be even.
There is no difference in that in Digital cameras from film.
http://photo.net/casual-conversations-forum/00VGF2
What exposure time did you use. It may be a certain exposure that is
worse thab others.
Hans
On Jan 27, 3:48 pm, "panogra...@gmail.com" <panogra...@gmail.com>
wrote:
> Hi,
>
> I am facing an unusual problem I cannot solve.
> It's about a partial panorama made of 4 rows and 52 columns from
> Nikkor 180mm.
> Of course shot in manual mode.
> The upper row, mainly sky and foggy mountains, shows horrible dark
> seams.
>
> At first sight I thought it was a bad vignetting setting from Capture
> NX. So I test with different settings
> but nothing changed, the crop I provide below is my best result... Ok
> It was far for a crystal day for landscape shoot, but I had to record
> the very unsusual snowy coat we had in the area.
>
> My first test was made with PTGui 8.3.6 then I update to a PRO version
> hoping to improve quality.
> I tried to blend an output with Enblend 4.0 without improvement.
>
> In the Exposure/HDR tab I tried checking "Exposure correction" button
> without improvemnt.
> What else could I do in this tab ?http://www.animatif.com/temp/stitch/PTgui_exposure.png
panog...@gmail.com
Joergen, I couldn't believe UV filter had an impact in such way, but I
have to
confess at obviousness, I did remove my BW UV filter for this shoot !
Don't know what happenned in my head that day...
So do you think this could be the explanation ?
Here's a sreenshot from the 14 NEF files used for the example stitch I
posted earlier :
http://www.animatif.com/temp/stitch/NEF_screenshot.jpg
(I told you, it was a bad day for landscape shooting !)
@ Ken, fisheye have different optical construction than tele lens and
this problem you're describing might be some chromatic aberration.
Post a sample and let's see.
@ Hans, it could be another wise explanation but I doubt the phenomena
appears at 1/1600s.
The D90 shutter travels from up to down, in portrait mode like here,
it's from left to right.
Watching the NEFs, I cannot say if there is a darker side or another.
What do you think ?
Unfortunately I can't go back to shoot again as snow has melted the
day after I made this panorama... :-(
Back in the old days, we did not have all these stitching
problems ;-)
Cheers,
G
Joergen Geerds
wrote:
> Here's a sreenshot from the 14 NEF files used for the example stitch I
> posted earlier :http://www.animatif.com/temp/stitch/NEF_screenshot.jpg
> (I told you, it was a bad day for landscape shooting !)
I looked at the thumbnails, and I can't see any UV flares in there...
they are just awfully low contrast, but seem to be fine otherwise. so
I would suggest you stitch from 16 bit tiffs, and reset all vignetting/
color correction values in ptgui to 0, and render it as blended+layers
to a PSB... ptgui has sometimes problems when it has to adjust the
exposure, potentially in conjunction with a vignetting setting: it
does sometimes introduce false colors (usually grayish) when it has to
do some sort of highlight recovery. so turning off all the adjustments
might get rid of the problem in this context.
if the blended result is fine, then simply discard the additional
layers in photoshop, if they still show up in the blended layer, but
not in the individual layers, simply blend the layers in photoshop.
> @ Hans, it could be another wise explanation but I doubt the phenomena
> appears at 1/1600s.
> The D90 shutter travels from up to down, in portrait mode like here,
> it's from left to right.
> Watching the NEFs, I cannot say if there is a darker side or another.
there is an ever so slight gradient from left to right, not more than
3 RGB values, so that shouldn't make any difference.
> Unfortunately I can't go back to shoot again as snow has melted the
> day after I made this panorama... :-(
well, you can always go back when the conditions are better :-)
joergen
Erik Krause
> In the Exposure/HDR tab I tried checking "Exposure correction" button
> without improvemnt.
> What else could I do in this tab ?
> http://www.animatif.com/temp/stitch/PTgui_exposure.png
You have a non-standard camera response curve. Try resetting it to
default. To optimize for camera response is needed for bracketed sets
only. Since you didn't enable HDR stitching a camera response curve
isn't needed and to try to determine one can cause weird results.
Did you try to optimize for vignetting? PTGui vignetting correction is
far better than anything you can adjust manually.
If the problem persists I think Hans is right: 1/1600s is a pretty short
exposure - you better would have stopped down and used a longer time. At
such a short time only a narrow slit moves across the sensor. If the
opening shutter is slightly slower or faster than the closing one you
get a varying exposure time across the image. This is the more
pronounced the shorter the exposure is, since a variation of 1mm is more
severe on a slit of 5mm width than on one of 20mm width.
--
Erik Krause
http://www.erik-krause.de
panog...@gmail.com
Joergen Geerds <jgee...@gmail.com> wrote:
> On Jan 28, 10:09 am, "panogra...@gmail.com" <panogra...@gmail.com>
> wrote:
>
> > Here's a sreenshot from the 14 NEF files used for the example stitch I
> > posted earlier :http://www.animatif.com/temp/stitch/NEF_screenshot.jpg
> > (I told you, it was a bad day for landscape shooting !)
>
> I looked at the thumbnails, and I can't see any UV flares in there...
> they are just awfully low contrast, but seem to be fine otherwise. so
> I would suggest you stitch from 16 bit tiffs, and reset all vignetting/
> color correction values in ptgui to 0, and render it as blended+layers
> to a PSB... ptgui has sometimes problems when it has to adjust the
> exposure, potentially in conjunction with a vignetting setting: it
> does sometimes introduce false colors (usually grayish) when it has to
> do some sort of highlight recovery. so turning off all the adjustments
> might get rid of the problem in this context.
Yes, very low contrast in the far foggy background, it was better in
the foreground, even if at this stage of the shoot the sun started to
disappear behind high clouds. See screenshot from NEF :
http://www.animatif.com/temp/stitch/screen_foreground.jpg
So I turned every settings to 0, optimized for vignetting and output a
blender and layer .psd file of a part of the 1st row. Here's a
screenshot :
http://www.animatif.com/temp/stitch/blender-layer-psd.jpg
(I did not make any curve or levels settings)
It looks better but not satisfying though...
From this .psd blender and layer output I copied and pasted 4 layers
side by side in a new document and it makes clear here that each layer
is darker on the left side. Screenshot here :
http://www.animatif.com/temp/stitch/screen_4layers.jpg
Might be the shutter travelling problem as Hans and Eric explain but I
also wonder if it's not simply because the sunlight are coming 90°
from the lens, on the right of each photo in my case, which would
explain the clearer right side...
I was taking a look lately at the Paris 26 gigapixels website and I
noticed in the preview jpeg they provide that it looks like they have
the same kind of dark seams in the background :
http://www.paris-26-gigapixels.com/en/wp-content/uploads/2010/01/p26G-preview.jpg
I think what I have to do now is give some long post prod working with
Photoshop to complete my panorama :-)
>
> well, you can always go back when the conditions are better :-)
Done ! but in summertime..
http://www.animatif.com/panoramas-HD/valence/plaine-de-valence-hd.html
And I'm afraid I'm not going to see snow here again in next months or
even years :-(
"A single conversation with a wise man is better than ten years of
study"
Cheers,
G.
>
> joergen
Hans
side.
Can be done easy with an action.
Hans
On Jan 30, 5:14 pm, "panogra...@gmail.com" <panogra...@gmail.com>
wrote:
> the same kind of dark seams in the background :http://www.paris-26-gigapixels.com/en/wp-content/uploads/2010/01/p26G...
>
> I think what I have to do now is give some long post prod working with
> Photoshop to complete my panorama :-)
>
>
>
> > well, you can always go back when the conditions are better :-)
>
> Done ! but in summertime..http://www.animatif.com/panoramas-HD/valence/plaine-de-valence-hd.html
Erik Krause
> From this .psd blender and layer output I copied and pasted 4 layers
> side by side in a new document and it makes clear here that each layer
> is darker on the left side. Screenshot here :
> http://www.animatif.com/temp/stitch/screen_4layers.jpg
If it is present in all images you can try to use a gradient mask to
reduce the difference further. The structureless sky gives you the
opportunity to do this quite simple in photoshop: First create a
rectangular selection in the featureless sky from left to right (not too
high), then create a levels adjustment layer and select levels such that
you get maximum contrast in the selected rectangle in order to see the
brightness difference very pronounced but not clipped. Go back to the
background layer and select a narrow (only some pixel) horizontal strip
from the featureless sky, copy it, remove selection, create another
adjustment layer and paste the selection into the mask channel. Expand
the strip vertically until it covers the whole image. Use Auto levels on
that mask, eventually use high radius gaussian blur to make it smooth.
Now you have a mask for removing the difference. The first created layer
should be top layer, you use it to see the difference clearly only.
Adjust the middle (levels) layer such, that the difference minimizes.
Apply this middle layer to all images (eventually create an action
droplet).
BTW: This was the workflow to remove non-standard vignetting before
there was vignetting correction in PTGui (using a circular mask of
course)...
panog...@gmail.com
On Jan 27, 5:58 pm, Hans <hans...@gmail.com> wrote:
> This is most certainly a shutter problem. Does not quite look like
> vignetting but that could also be contributing.
> Most shutters are travelling on the short side and if they do not do
> that even the exposure will not be even.
>
>
> What exposure time did you use. It may be a certain exposure that is
> worse thab others.
>
> Hans
Hi,
Back on topic, better late than never, but I did not take the time to
work on this pano lately.
Now, about the shutter problem, I'm pretty sure you are right Hans !
I made a test shot on a grey sky at the same settings (1/1600s f:6.3)
and same behavior appears.
Here's a side by side image :
http://www.animatif.com/temp/stitch/1600s_x_2.jpg
I shot a test panorama yesterday with my 180mm but at 1/800s f:9 this
time, here's a small output from PTGui :
http://www.animatif.com/temp/stitch/pano180mm.jpg
Beside moving cloud's shadow on the snow this stitch looks ok to me.
For memory see what I got with my previous panorama :
http://www.animatif.com/temp/stitch/crop_sky.jpg
@Eric
Thank you very much for you help but I must say I had a hard time to
reproduce your last explanation ;-)
Anyway I played with a linear gradient mask and finally the output
from PTGui was acceptable, here's a small crop of the left part of the
pano :
http://www.animatif.com/temp/stitch/plaine_gauche2.jpg
Some soft dark seams remain but it should be easy to remove straight
on the panorama.
Cheers,
G.