Size of equirect different from one 360° pano to another !?!
JPS
chosing "Set Maximum Size", is each time different ? I had results
from +/- 3580 to +/- 6800 pixels, going thru all figures in between...
I allways use the same camera/lens/pano-head (D700+Nikon 10.5 shaved),
and I first use 4 shots around ! The Nadir shot comes in later...
Any idea why the equirect size isn't allways the same ?
???
J-P.
Sacha
different.
PTGui Support
For each panorama you will have control points at different locations.
PTGui calculates the lens parameters based on the control points and
this results in slightly different values each time. The optimum size is
based on the lens parameters.
Of course you are free to choose any output size; the optimum size is
just a recommendation.
Joost
JPS
Thanks for the quick answers !
Thing is, I let PTGui set the lens parameters and I NEVER crop (PTGui
does it well enough) !
Another thing: when I load the images, PTGui find from the Exifs that
I use a 10.5mm. lens with 180° HFOW, but it allways ends-up giving F-
length between 9.xx and 12.xx mm., as well as HFOW between 175 and
210, all by itself... EVEN THOUGH the camera/lens/pano-head settings
are ALLWAYS the same !
Still puzzled...
J-P.
Sacha
The more proper your set of control points, the closer that your lens
parameters will be accurate.
If you want to save yourself a ton of time and decrease stitching
errors, you should use exact and correct lens parameters rather than
shmushing your images into shape that covers a sphere which is what
quick optimizing does based on willy nilly control points giving you
lens focal lengths from 9-12.
You must have a crop camera then if you don't need to crop your
images. For full frame cameras, setting the image circle to match is
fairly important to achieve a decent focal length and consistent lens
parameters.
Probably you should be using circuluar fisheye instead of fullframe
anyway and set your image circle exactly. It's been awhile since I
used the 10.5 on a crop sensor. It may be ok either way.
JPS
Now, from your answer above:
1) how can I know "the exact and correct lens parameters" since PTGui
gives me everytime different figures ?
2) I use a D700, hence fullframe camera, and I let PTGui find the good
croping automatically
3) PTGui allways find -in the Exifs- that the lens is a CIRCULAR
FISHEYE, and it's a 10.5mm., BEFORE to align/add CPs, but after that,
it changes the figures, giving different F-length and HFOV figures !
OK... in the end, I -almost- allways manage to get a good result, but
I'd like to know if there are "ready-made" PTGui settings for the
combo D700+10.5, so that I could set them as DEFAULT or TEMPLATE ?
...or else, -hence the PTGui setting are each time different-, how on
hearth can I know which set of settings is THE good one, so that I can
save them and re-use in the future ?
J-P.
Erik Krause
> 1) how can I know "the exact and correct lens parameters" since PTGui
> gives me everytime different figures ?
There is no single "exact and correct" set of lens parameters for
fisheye lenses. Neither the focal length nor the lens correction
parameters are exactly defined for a given lens.
Furthermore lens correction parameters and focal length influence each
other, there are several sets of parameters which give almost the same
result. Very tiny differences in control point position can cause PTGui
to decide for one or the other set of parameters.
This is especially true for a shaved Nikkor 10.5, since it uses a
somehow unusual mapping and the outer regions are predominantly affected
by this mapping differences.
--
Erik Krause
http://www.erik-krause.de
John Houghton
> 1) how can I know "the exact and correct lens parameters" since
> PTGui gives me everytime different figures ?
in a suitable venue having a plentiful supply of features for control
points in all directions and stitch very carefully to get an excellent
result. For further advice on workflow, do a search of this forum for
"optimize 10.5mm Hans". Also read: http://wiki.panotools.org/Optimization
.
Save the project file for use as a template for future stitches. When
the images have been loaded and the template has been applied (from
the File menu), generate control points from the control points menu
in Advanced mode, then optimize only lens fov and the horizontal and
vertical shift parameters (+ y,p,r on all images except one). The fov
will remain very close to its initial value. Use the "Delete worst
points" option to eliminate bad points and reoptimize. That should
usually get you close to a good stitch.
> 2) I use a D700, hence fullframe camera, and I let PTGui find the
> good croping automatically
inside the image circle when making your template project.
I've uploaded a template file made from a stitch of some sample images
I happened to have in my archives, which may help you on your way even
if it doesn't quite give you a perfect stitch:
www.johnhpanos.com/D700-105-template.zip
It can be applied to images supplied to PTGui in portrait orientation:
4 around + Z + N.
John
John Houghton
> I've uploaded a template file made from a stitch of some sample images
> I happened to have in my archives, which may help you on your way even
> if it doesn't quite give you a perfect stitch:
>
> www.johnhpanos.com/D700-105-template.zip
front:
http://www.johnhpanos.com/D700-105-template.zip
John
Roger D. Williams
On Thu, 09 Dec 2010 20:29:04 +0900, JPS <jpsch...@infomaniak.ch> wrote:
> Hi Sacha !
And Sacha will probably give you a better answer than I can. But in the
mean time I'll jump in with a simple answer.
> Now, from your answer above:
>
> 1) how can I know "the exact and correct lens parameters" since PTGui
> gives me everytime different figures ?
> 2) I use a D700, hence fullframe camera, and I let PTGui find the good
> croping automatically
> 3) PTGui allways find -in the Exifs- that the lens is a CIRCULAR
> FISHEYE, and it's a 10.5mm., BEFORE to align/add CPs, but after that,
> it changes the figures, giving different F-length and HFOV figures !
You do one, very careful and accurate "stitch" with the lowest possible
error you can achieve, and with no visible stitching errors however hard
you look. Then you load the lens settings to the lens database and select
that lens from the database for your subsequent panoramas. Simple!
That'll give you a good start. It means, if I am right, that PTgui can
get on with the business of warping things to fit in the certainty
that the lens settings are all VERY close to optimum.
> OK... in the end, I -almost- allways manage to get a good result, but
> I'd like to know if there are "ready-made" PTGui settings for the
> combo D700+10.5, so that I could set them as DEFAULT or TEMPLATE ?
The first default is the lens settings that you can store along with
the name of the lens. FOr instance I use a Sigma 8mm lens with my D300
and a Peleng 8mm with my Pentax K-x. I have both lenses listed and
make sure to select the right one.
> ...or else, -hence the PTGui setting are each time different-, how on
> hearth can I know which set of settings is THE good one, so that I can
> save them and re-use in the future ?
But since I shoot hand-held and with a monopod, I don't get into the
business of templates as the other parameters are too variable. But I
DO select the right lens/parameters, and so -- probably -- should you.
Roger W.
--
Business: www.adex-japan.com
Pleasure: www.usefilm.com/member/roger
Sacha
lens parameters are used from the outset you'll get higher cp errors
which is good not bad. Meaning that your lens isn't being smushed into
a weird shape to accommodate bad control points which are then left
out to dry. And these sore thumbs are easier to delete.
John Houghton
> Then you load the lens settings to the lens database and select
> that lens from the database for your subsequent panoramas. Simple!
have carefully set does not get stored in the lens database. The lens
parameters can vary with the crop parameters, so it is preferable in
the case of circular fisheyes to use the template feature to set the
lens parameters, as this does set the crop parameters too. This has
the additional benefit of (optionally) initializing the image and
optimization parameters, all of which save work and help the optimizer
to deliver a good alignment more reliably.
John
Roger D. Williams
I see the force of what you say, John, but doesn't the fact that I shoot
mostly hand held and/or with a monopod mean that I would be better to
avoid templates? I will try what you suggest but still have the concerns
that discouraged me from trying this originally. I do consistently get
average errors of one or two pixels and a maximum of three to five, so
I am fairly happy with the results and don't have much trouble with
seams these days...
Roger W>
John Houghton
> I see the force of what you say, John, but doesn't the fact that I shoot
> mostly hand held and/or with a monopod mean that I would be better to
> avoid templates?
who has a standard workflow with a panohead and circular fisheye. I,
too, have made a large proportion of my panoramas with a handheld
camera but usually with a standard shooting pattern for which a
template is still useful. I think it even more important to use
accurate lens parameters (and not optimize them) for handheld panos.
It is all too easy for parallax effects to inadvertently cause
unwelcome distortions otherwise. But we all develop individual ways
of doing things that work for us, and if you are happy with your
present workflow then stick with it. It's the end rersult that
matters, not how you got there.
John