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--J. Brian Caldwellwww.caldwellphotographic.comUsers of zoom lenses with a 28 mm focal length, have you
experienced any such irregular gull wing distorsion at wide angle
with your DSLR? Any remedy or workaround for that?
http://www.dpreview.com/forums/read.asp?forum=1024&message=1452386
Regards
John
Panorama Tools is superb for correcting this type of distortion
because it gives you several different coefficients to play with:
http://www.caldwellphotographic.com/TutorialsDistortionAndColorFringing.html
http://www.caldwellphotographic.com/cc02485at24.html
http://www.caldwellphotographic.com/cc15mm35.html
http://www.caldwellphotographic.com/cc20mm28.html
Brian
--Users of zoom lenses with a 28 mm focal length, have you
experienced any such irregular gull wing distorsion at wide angle
with your DSLR? Any remedy or workaround for that?
http://www.dpreview.com/forums/read.asp?forum=1024&message=1452386
Regards
John
J. Brian Caldwell
http://www.caldwellphotographic.com
Panorama Tools are great but only if you have an unlimited time to
work out the settings. The wavy lines change depending on the zoom
setting making Panorama Tools a real chore. Iknow, I still have all
the repeatable tables that I calculated for my Nikon 950/990. A
better solution for Chroma and Barrel is
here. http://www.theimagingfactory.com/
I have the Debarrelizer and it corrects barrel distortion and
Chroma with an instant enlargable preview. I believe they let you
download the software and give you a 30 day free preview. The gull
wing/ tilde distortion is to be avoided in your shots and I would
not take the time to try to get rid of the waves.
Rinus
--J. Brian Caldwellwww.caldwellphotographic.compicture and i am afraid this is beyond the capabilities of
Debarrelizer. This type of distortion can only be corrected (if at
all) with Helmut Derschl pano tools, or possibly with LensDoc.
Oscar Rysdyk,
///////////////////////////////// http://www.theimagingfactory.com
/////////////////////////////////
What would have been nice would be the possibility to disable the
in-camera correction of distorsion, and correct them with software
(Debarrelizer for example) which would be much easier. Wawe like
distorsions would be avoided I believe.
Regards
John
Panorama Tools are great but only if you have an unlimited time to
work out the settings. The wavy lines change depending on the zoom
setting making Panorama Tools a real chore. Iknow, I still have all
the repeatable tables that I calculated for my Nikon 950/990. A
better solution for Chroma and Barrel is
here. http://www.theimagingfactory.com/
I have the Debarrelizer and it corrects barrel distortion and
Chroma with an instant enlargable preview. I believe they let you
download the software and give you a 30 day free preview. The gull
wing/ tilde distortion is to be avoided in your shots and I would
not take the time to try to get rid of the waves.
Rinus
John:
Are those full frame shots, or are they cropped at all. I get
reasonable correction in those D7 images by setting the "a"
coefficients to +0.04, the "b" coefficients to -0.09, and the "d"
coefficients to +1.05. This gets rid of most of the distortion,
but there seems to be some assymetry. By the way, thats probably
the worst case of gull wing distortion I've ever seen!
Brian
--J. Brian Caldwellwww.caldwellphotographic.comBest Regards
John
John:
Are those full frame shots, or are they cropped at all. I get
reasonable correction in those D7 images by setting the "a"
coefficients to +0.04, the "b" coefficients to -0.09, and the "d"
coefficients to +1.05. This gets rid of most of the distortion,
but there seems to be some assymetry. By the way, thats probably
the worst case of gull wing distortion I've ever seen!
Brian
I've tried a CP5000 for a short time, and it seems like a pretty
decent camera. I did shoot some test images for distortion, and it
seems to be simple barrel at the short focal length end with little
or no gull wing. You can also get down to 19mm equivalent on the
Coolpix using a 0.68x converter. If it were me, I'd probably go
with the Nikon over the Minolta for architectural photography.
Brian
--Best Regards
John
John:
Are those full frame shots, or are they cropped at all. I get
reasonable correction in those D7 images by setting the "a"
coefficients to +0.04, the "b" coefficients to -0.09, and the "d"
coefficients to +1.05. This gets rid of most of the distortion,
but there seems to be some assymetry. By the way, thats probably
the worst case of gull wing distortion I've ever seen!
Brian
J. Brian Caldwell
http://www.caldwellphotographic.com
What a problem this little thing can be. But your minolta lens is
not the only one, the 17mm Tamron lens has it too. This shows you
that the effect is totally in the lens. I already knew that the
debarrelizer does not get rid of the wavies but I think it is a lot
easier to only correct for the barrel distortion which is the
center 3/4 part and then go to the panorama tools to get rid of the
remaining pincushion distortion at in he corners. The Debarrelizer
is fast and easy to use and will correct for the Chroma in one
sweep without using formulas. It is fast for any zoom setting. If
you then must use the panorama tools, you only have to set a single
parameter to get rid of the remaining pin at the corners.
Rinus
I have a 990 and the WC-E24 (0.66x) wide converter has a lot of
barrel distortion but the debarrelizer can correct it. The WC-E63
(0.63x) or the WC-E68 (0.68x) may also have gull wing distortion. I
bought the older one of these two (sorry I do not remember which)
and found the same wavies. I went back to the older WC-E24 and use
the debarrelizer. I would test them on some straight lines and
return it if it is not going to do the trick!.
Rinus
Users of zoom lenses with a 28 mm focal length, have you
experienced any such irregular gull wing distorsion at wide angle
with your DSLR? Any remedy or workaround for that?
http://www.dpreview.com/forums/read.asp?forum=1024&message=1452386
Regards
John
Brian
Users of zoom lenses with a 28 mm focal length, have you
experienced any such irregular gull wing distorsion at wide angle
with your DSLR? Any remedy or workaround for that?
http://www.dpreview.com/forums/read.asp?forum=1024&message=1452386
Regards
John
I've tried a CP5000 for a short time, and it seems like a pretty
decent camera. I did shoot some test images for distortion, and it
seems to be simple barrel at the short focal length end with little
or no gull wing. You can also get down to 19mm equivalent on the
Coolpix using a 0.68x converter. If it were me, I'd probably go
with the Nikon over the Minolta for architectural photography.
Brian
--Besr Regards
John
I've tried a CP5000 for a short time, and it seems like a pretty
decent camera. I did shoot some test images for distortion, and it
seems to be simple barrel at the short focal length end with little
or no gull wing. You can also get down to 19mm equivalent on the
Coolpix using a 0.68x converter. If it were me, I'd probably go
with the Nikon over the Minolta for architectural photography.
Brian
John:
Without proper test images there's not much I can do. You might
want to try stepping through my tutorial to do the calibration
yourself. Once you get the hang of it its really pretty
straightforward.
Brian
Panorama Tools is great if you only left that zoom control alone. I
do not shoot at any particular zoom setting as that removes the
benefit of having one. Recalculating is a pain in the butt. I have
all the tables calculated for Pan Tools at all the normal ranges.
Wide,Tele, middle needs none except some fringing. Wide with the
adapter as well even the chroma settings on my 180 degree fisheye.
So much for having zoom lenses with fixed settings. As far as the
Debarrelizer goes, you probably did not try it out as it will do
both chroma/fringing and barrel distortion in one click. You can
also scale the image to the horizontal or vertical straight edge
full crop as well as replicate/fill the empty areas or leave it all
alone and let you do the crop after. Granted, Panorama Tools is
free but it is only for people with slide rules and calculators. it
took me hours to calculate and try all the settings for the Nikon
950 and had to do it again with the 990. Then I used my wide lenses
and zooms on my 35mm Nikons and gave up. Downloading settings from
somewhere else does not work either due to manufacturing
differences in the lenses. The proof is in the Panorama tools help
file where the Nikon 950 was used with a wide 24 adapter. The
settings were not correct on my system. The chroma was worse and
the barrel distortion was still somewhat barreled. Thanks guys for
the freebees but I rather pay a little to get a lot more and work
fast and efficient.
Rinus
