Wider lens for keystone correction?


CamInit

New Member
Nov 3, 2009
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#1
Was correcting firework shots in CS5 when I realized it results in significant loss from the correction and cropping to remove the keystone distortion. The first impulse was to think of getting an even wider lens (10mm to 8mm on 1.6x crop). I believe going even wider would create even more distortion which means more cropping when correcting? The question is thus, does the two cancel out or can I retain more of the picture (using a shorter focal length) after keystone correction?
:think:
 

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Kit

Senior Member
Jan 19, 2002
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#2
You get keystone effect when your camera and lense is not aligned to the object you are photograhing. To some extend, wide angle lenses do help because the wider angle of view gives you better chance to align your setup to your objects. However, there is a limit of what they can do.
 

giantcanopy

Senior Member
Feb 11, 2007
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#3
Kit has explained the issue of falling verticals.

With a wider lens , u have a better chance of getting the sensor aligned parallel to that of the verticals in your scene and yet include much of the action because of wider coverage. But comes with a price of doing crop ( i suppose u might not want too much of the lower half below the horizon ).

ryan
 

giantcanopy

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#5

dingaroo

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Dec 6, 2009
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#6
For the ultimate in quality, get something like a GSX680 or a view camera. :devil:

http://www.luminous-landscape.com/reviews/cameras/gx680iii.shtml

http://en.wikipedia.org/wiki/View_camera

Failing which, get a Tilt-Shift lens and learn how to stitch.
And carry a tripod weighing 25kg like you? Hahahaha!

Anyway, was great to see you again last Saturday, though could have been in slightly better location.

TS: Maybe next time try to orientate your camera to portrait orientation. Make sure you put on a bubble leveler to ensure you are horizontally and vertically level to avoid keystone effects.

Or like DM recommended, a Tilt-Shift lens may help solve the problem, but it will cost a lot more than an ultra wide angle. And to operate it is not easy. U can google it.

Cheers.
 

CamInit

New Member
Nov 3, 2009
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#7
ok, thanks for the replies. I suppose 8mm also wouldn't resolve the problem completely for my case where the keystone distortion is quite extreme. The fireworks were almost overhead and I was hoping to include in the horizon for composition. Now it occurred to me wondering how well would the Canon 8-15mm do after de-fishing? :think:
 

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