Interesting Comment Found in a RR Photography Book

[s8langwo]

I recently came across a comment made by Alvin Stauffer who is a respected author and photographer on the subject of the Pennsylvania Railroad.

He mentioned (in Pennsy Power II) that the focal plane shutter gives photographs of moving trains a slant that imparts the impression of speed. I n't have the exact wording in front of me, so please forgive if I am misunderstanding.

I enjoy his books and colorful commentary, but was wondering if anyone here has noticed this effect? If you have, under what conditions/settings is it most prevalent?

Thanks,
Kevin
A Pennsy Fan in MI!

[asylumxl]

I think what he is talking about is rolling shutter distortion. alot of cheap/low spec cameras suffer from it. Think of it like someone drawing an image from top to bottom in loads of little lines (and the speed of light). As the train moves through frame, the resulting lines end up shifted to the side with each line, creating a diagnol skew.

[Belmondo]

Here's an example of the phenomenon in a vintage race car photo

The camera is panning, so the grandstands seem to tip one way, and the car moves forward as the shutter move across the image making it look like its tires are oval and it's leaning forward.

[s8langwo]

Belmondo,

Thanks so much for the excellent example. Really neat. Might have to try to apply it during some rail fanning I'll be doing later this summer.

Thanks,
Kevin

[Box Brownie]

Hmmmm!!!

I wonder if such distortions are now hardly seen because all (?) modern dSLRS use horizontal focal plane shutters whereas if you go bcak not that many years or at least predigital there were many makes/models that used vertical focal plane shutters. I have yet to look but feel sure that somewhere there is a wiki or Google ref taht might mention the differences such as the effect you mention and Belmondo posts an image of. On that note if I recall the vertival focal plane shutters had a reputation that as they aged (note the shutter curtains were made of cloth) the actual speed would accelerate ~ I think the old Canon AE-1 was one such camera and I read you could get a judge of its age by the "chug" noise the shutter made.

:)

OK found a page that "talks" about focal plane shutters and distortions here http://www.wrotniak.net/photo/tech/fp-shutter.html must read it more completely myself!