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Removing lens distortion with panorama tools plugin

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jason Langadakis

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I have read several articles about how to calibrate your lens with panorama tools to remove the barel effect of the lens with the PT plugin.

I follow the door example described by many experts but I can't seem to get that terrible powershot G2 distortion to align properly.

Does anybody have experiance with panorama tools and possibly the distortion numbers for G2 lens?

I would really appreciate some help from the pros.

Thanks
 
interested in reading replies. I have PTMAC (Licenced version) and I am struggling to make it work very well. Some other peoples results are fantastic. Mine are quite ordinary.....

I'll watch with interest.

--

------------------------------
Live life, it's the only one you've got . . . . . '
 
From what I read all the pros seem to use panorama tools. But the software is very dificult to use and I haven't found any calibration settings for canon g2 lens. There is good info for nikon and minolta 7i lenses but not canon.

I have tried the calibration for g2 with panorama but I just got OK results by trying varous calibration values by trial and error.
Don L said:
Try this website. There may be some answers there.

http://www.panoguide.com/

--
Don L
Click to expand...
 
anyone know, Will Panotools work in OSX... dont see it specifically listed... just Mac Os...

Thanks
 
Scott,

From the intro at the following site;

http://epaperpress.com/pano/index.html

Quote;

Several excellent programs have been written that interface to Panorama Tools: PTGui, written by Joost Nieuwenhuijse, and PTAssembler, by Max Lyons, supply a Windows interface. PTGui is available for a modest sum, and PTAssembler is free. PTMac, a version for the Macintosh written by Kevin Kratzke, is also available. Screen snapshots in this document are based on PTGui.

unquote.

Brian.
Scott Ratner said:
anyone know, Will Panotools work in OSX... dont see it specifically
listed... just Mac Os...

Thanks
Click to expand...
 
Thanks Brian, this is a great resourse.

Unfortunately i didn't find the calibration values for G2 anywhere in here.

I actually didn't see any sample shot with a G2 although there is some amazing work done with nikons and minoltas.

Does anybody have any interesting photos done with pt tools and a G2?
I would like to see that.

Thanks again for a very good pointer.

Jason Langadakis
Brian Thomas said:
Check out the following site, one of the best I've seen.

http://epaperpress.com/pano/index.html

Brian
jason Langadakis said:
I have read several articles about how to calibrate your lens with
panorama tools to remove the barel effect of the lens with the PT
plugin.
Click to expand...
Click to expand...
 
You might look at LensDoc from Andromeda. It works pretty well for removing lens distortions, perspective distortion and also does rotations. You can build you own correction set for you lenses. Some sets are provided for some cameras.
 
Hi Rob,

Let me know if you need any tips on using PTMac/Panotools. I've learned a number of tips and tricks from some professional photographers as I developed PTMac. I've also become painfully aware of the limits of my little Coolpix 990.

For the poster asking if Panotools runs on OS X. Yes it does. I ported the library to OS X (the only part of PTMac that is opensource) and re-created the Photoshop plug-ins for Photoshop on OS X. There is also a PTMac version for OS X.

My current projects are to improve the interface of the plug-ins and then upgrade PTMac.

Finally, this may not be much interest to Canon users, but I have a database of lens correction factors for Nikon lens correction factors for Nikon digital SLR cameras from Brian Caldwell. These should work in any version of the Panotools plug-ins (Mac and Windows) and are free for the asking. I tried to get some loaner equipment from Canon but my requests apparently fell on deaf ears.
 
Jason:

I found some excellent test images from the Minolta D7 by Marko Bjorkroth, and was able to publish some correction factors: http://www.caldwellphotographic.com/D7Distortion.html

If you or anyone else can supply test images I could do a similar calibration.

The key to using Panorama Tools for fixing distortion is to use a little optical knowledge to reduce the number of variables. For instance, simple barrel or pincushion distortion is a cubic function, so you only need to worry about the "b" parameter in Panorama Tools. This is explained to some extent in my tutorial on correcting distortion and lateral chromatic aberration: http://www.caldwellphotographic.com/TutorialsDistortionAndColorFringing.html

Brian
http://www.caldwellphotographic.com
jason Langadakis said:
I have read several articles about how to calibrate your lens with
panorama tools to remove the barel effect of the lens with the PT
plugin.

I follow the door example described by many experts but I can't
seem to get that terrible powershot G2 distortion to align properly.

Does anybody have experiance with panorama tools and possibly the
distortion numbers for G2 lens?

I would really appreciate some help from the pros.

Thanks
Click to expand...
--
J. Brian Caldwell
http://www.caldwellphotographic.com
 
Leon Wittwer said:
You might look at LensDoc from Andromeda. It works pretty well for
removing lens distortions, perspective distortion and also does
rotations. You can build you own correction set for you lenses.
Some sets are provided for some cameras.
Click to expand...
--
Walter K
 
Jason,

I have been down this path also. I found the program DEFISH at versiontracker. It is totally free. It worked as well as PTMAC for the one image I tested.

Here is a link

http://www.versiontracker.com/moreinfo.fcgi?id=1167&db=mac

Jeff
jason Langadakis said:
I have read several articles about how to calibrate your lens with
panorama tools to remove the barel effect of the lens with the PT
plugin.

I follow the door example described by many experts but I can't
seem to get that terrible powershot G2 distortion to align properly.

Does anybody have experiance with panorama tools and possibly the
distortion numbers for G2 lens?

I would really appreciate some help from the pros.

Thanks
Click to expand...
--
Jeffrey P. Kempster
Louisville, KY, U.S.A.
http://www.kempstertimes.com/
 
I would be glad to supply you with test images but first I would need some instructions on exactly what is a good calibration image.

I've read your article and I've tried to calibrate based on your method but I get OK (not perfect results).

I undersand that I have to provide you with a separate test image at each major focal length. Doesn't the actual distance of the object change the distortion also? for example do i get the same calibration numbers from an image at 3 feet distance and an image at 20 feet?

Please let me know toy requirements for the test images and I'll be glad to provide them to you/

Thaqnks for your help.
brian said:
If you or anyone else can supply test images I could do a similar
calibration.

The key to using Panorama Tools for fixing distortion is to use a
little optical knowledge to reduce the number of variables. For
instance, simple barrel or pincushion distortion is a cubic
function, so you only need to worry about the "b" parameter in
Panorama Tools. This is explained to some extent in my tutorial on
correcting distortion and lateral chromatic aberration:
http://www.caldwellphotographic.com/TutorialsDistortionAndColorFringing.html

Brian
http://www.caldwellphotographic.com
jason Langadakis said:
I have read several articles about how to calibrate your lens with
panorama tools to remove the barel effect of the lens with the PT
plugin.

I follow the door example described by many experts but I can't
seem to get that terrible powershot G2 distortion to align properly.

Does anybody have experiance with panorama tools and possibly the
distortion numbers for G2 lens?

I would really appreciate some help from the pros.

Thanks
Click to expand...
--
J. Brian Caldwell
http://www.caldwellphotographic.com
Click to expand...
 
Is (or was) a freeware plugin for photoshop to correct barrel distortion.

It loads a preview window and a box to insert % change. The default is usually about right but it's simlplicity itself to just increase or decrease the % until the lines look straight. The whole thing can be performed in a couple of seconds with perfect results.
I've put the freeware on my site for you to try if you like. 24kb download.
http://www.action-bookmark.fr/ian/DBRLFW102W.ZIP
regards
Ian
Jeffrey P. Kempster said:
I have been down this path also. I found the program DEFISH at
versiontracker. It is totally free. It worked as well as PTMAC for
the one image I tested.

Here is a link

http://www.versiontracker.com/moreinfo.fcgi?id=1167&db=mac

Jeff
jason Langadakis said:
I have read several articles about how to calibrate your lens with
panorama tools to remove the barel effect of the lens with the PT
plugin.

I follow the door example described by many experts but I can't
seem to get that terrible powershot G2 distortion to align properly.

Does anybody have experiance with panorama tools and possibly the
distortion numbers for G2 lens?

I would really appreciate some help from the pros.

Thanks
Click to expand...
--
Jeffrey P. Kempster
Louisville, KY, U.S.A.
http://www.kempstertimes.com/
Click to expand...
--
6900
 
Hi Jason:

For small digicams, shooting even a modest sized test target like an 8.5x11" piece of graph paper is optically about the same as shooting at infinity. For larger DSLR cameras I normally shoot a door or window frame. The key is to make sure that target contains at least one perfectly straight line located parallel to the edge of the image frame.

One possible reason you may have had difficulty getting perfect results is that your lens might have a trace of gullwing distortion. This would require use of the "a" parameter in Panorama Tools, and it makes the calibration process significantly more complicated. This was certainly the case for the shorter focal length positions in the Dimage7.

Brian
jason Langadakis said:
I undersand that I have to provide you with a separate test image
at each major focal length. Doesn't the actual distance of the
object change the distortion also? for example do i get the same
calibration numbers from an image at 3 feet distance and an image
at 20 feet?

Please let me know toy requirements for the test images and I'll be
glad to provide them to you/

Thaqnks for your help.
brian said:
If you or anyone else can supply test images I could do a similar
calibration.

The key to using Panorama Tools for fixing distortion is to use a
little optical knowledge to reduce the number of variables. For
instance, simple barrel or pincushion distortion is a cubic
function, so you only need to worry about the "b" parameter in
Panorama Tools. This is explained to some extent in my tutorial on
correcting distortion and lateral chromatic aberration:
http://www.caldwellphotographic.com/TutorialsDistortionAndColorFringing.html

Brian
http://www.caldwellphotographic.com
jason Langadakis said:
I have read several articles about how to calibrate your lens with
panorama tools to remove the barel effect of the lens with the PT
plugin.

I follow the door example described by many experts but I can't
seem to get that terrible powershot G2 distortion to align properly.

Does anybody have experiance with panorama tools and possibly the
distortion numbers for G2 lens?

I would really appreciate some help from the pros.

Thanks
Click to expand...
--
J. Brian Caldwell
http://www.caldwellphotographic.com
Click to expand...
Click to expand...
--
J. Brian Caldwell
http://www.caldwellphotographic.com
 
This is exactly the case with the g2 lens at full wide angle.

I followed your example of calibrating based on a window frame but I couldn't get it to work perfectly without compensating for "a" parameter.
This made it virtually imposible to calibrate based on your method.

I have found that PTGui does a better job at coming up with good calibration but it requires significant effort to calibrate at various focal lengs.

I was hoping that someone must have done that for G2 so I don't have to go through the trouble.

Regarding focal distance, I seem to get significantly higher barrel distortion at short distances than on long distance. I haven't done a test yet but this is my perception. It would be very nice if the distance doesn't matter on the calibration. That youd make it a lot simpler.

If I find some time this week I'll try to calibrate at several focal lengths with a grid paper and I'll share the results with you to let me know if I'm doing it right.

Thanks a lot for all your help, and your very informative web site.

Regards
Jason Langadakis
brian said:
One possible reason you may have had difficulty getting perfect
results is that your lens might have a trace of gullwing
distortion. This would require use of the "a" parameter in
Panorama Tools, and it makes the calibration process significantly
more complicated. This was certainly the case for the shorter
focal length positions in the Dimage7.

Brian
jason Langadakis said:
I undersand that I have to provide you with a separate test image
at each major focal length. Doesn't the actual distance of the
object change the distortion also? for example do i get the same
calibration numbers from an image at 3 feet distance and an image
at 20 feet?

Please let me know toy requirements for the test images and I'll be
glad to provide them to you/

Thaqnks for your help.
brian said:
If you or anyone else can supply test images I could do a similar
calibration.

The key to using Panorama Tools for fixing distortion is to use a
little optical knowledge to reduce the number of variables. For
instance, simple barrel or pincushion distortion is a cubic
function, so you only need to worry about the "b" parameter in
Panorama Tools. This is explained to some extent in my tutorial on
correcting distortion and lateral chromatic aberration:
http://www.caldwellphotographic.com/TutorialsDistortionAndColorFringing.html

Brian
http://www.caldwellphotographic.com
jason Langadakis said:
I have read several articles about how to calibrate your lens with
panorama tools to remove the barel effect of the lens with the PT
plugin.

I follow the door example described by many experts but I can't
seem to get that terrible powershot G2 distortion to align properly.

Does anybody have experiance with panorama tools and possibly the
distortion numbers for G2 lens?

I would really appreciate some help from the pros.

Thanks
Click to expand...
--
J. Brian Caldwell
http://www.caldwellphotographic.com
Click to expand...
Click to expand...
--
J. Brian Caldwell
http://www.caldwellphotographic.com
Click to expand...
 
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