Vertical geometrical distortion using 35 mm prime lens

[j.a.]

Hello every one,

 

 

I used a 35 mm f/ 2,8 prime lens for taking some nice arhitectural

frames and, as usually, I expected to have a little vertically

geometric distortion on my pictures printed in a 11 X 17 cm format.

Still, I find this resulting vertical distortion as beeing too

exagerated for the focal length I had used and I was wondering if

there were an acceptable limit for this type of distortion.

Maybe I was situated too close, I don�t know what exactly

happend. For wide-angle experts, take a look if time is not running.

 

Thanks.

[pico_digoliardi]

To the high-end photographer, that lens has unacceptable distortion; there are wider lenses with less than that. To minimize problems you should keep the film/sensor plane parallel to the front of the buildings.

 

What brand of lens is it?

[steve_unsworth1]

It looks as if you had the camera pointing down slightly, hence the diverging verticals. If you have Photosop CS2 you can use the lens distortion filter to fix this in a couple of mouse clicks.

[j.a.]

Ok, I see better now where the problem should be.

 

It is a W. Rokkor Md 35 mm f/2,8 stopped down at f/8. I used a anti-UV Hama filter on the lens.

 

J.A.

[eric friedemann]

"Ok, I see better now where the problem should be. It is a W. Rokkor Md 35 mm f/2,8 stopped down at f/8. I used a anti-UV Hama filter on the lens."

 

 

I doesn't sound like you understand the problem. That you used a Minolta lens at f/8.0 with a UV filter is irrelevant.

 

 

For even the best rectilinear wide angle lens, to reproduce straight vertical lines, the lens must be be parallel to the gound when shooting. If the camera is pointed a little up or a little down, you won't get straight, absolutely vertical lines.

 

 

As is noted, the problem can be largely corrected in Photoshop:

 

 

http://www.kenrockwell.com/tech/perspective.htm

[j.a.]

By no means I wish to say that it was my 35 mm lens fault, I just answered at the first question addressed by Pico diGoliardi.

 

J.A

[frank uhlig]

What some people (including you) call "wide-angle distortion" is simply perspective rendition of a scene and has nothing to do with lens performance. Rectilinear lenses are designed to give a perspective view.

 

If you want your pics not to have converging parallel lines, you must keep the film plane parallel to the plane of the lines, i.e., the vertical plane of the city scene in your pic. {Get a tripod, and use a bubble level on the hot shoe for example; or get an E-screen for your SLR viewfinder and check the proper alignment of the camera through the viewfinder (not too accurate, I am afraid)]

If you tilt down (or up), the lens gives no more and no less than a true rectilinear perspective.

 

Sorry, operator error, I am afraid.

 

Other distortions of lenses such as barrel and pincushion, chromatic aberrations etc are lens errors; this one is all yours.

 

Only that wide angle lenses are less forgiving in us noticing the lack of precision in shooting in the pics afterwards. But that is not their faul.