Lenses on Crop Sensor Cameras and Distortions

hanhasgotqi wrote:

J A C S wrote:

If you want to minimize those distortions, choose longer FL's or do not allow people near the borders. Another option is to use software correcting "volume anamorphic distortions" like DXO's ViewPoint. See this, for example. I use it often and the effect is very nice.

You guys are the best! Thank you for taking the time to answer my questions.

I searched and read a little more on barrel/pincushion distortions and perspective. As msowsun and BAK pointed out, I’ll back away at least 10’ to make sure perspective distortions are at a minimum. I can always crop down to a headshot for my purpose; the headshots don’t have to be pretty, as long as they show how the faces look.

To JACS, I am guessing the example you linked to is a kind of barrel distortion? Am I right in saying it is inherent in most wide angle lenses?

no, not necessarily. primes tend to be better than zooms, and in zooms it's mostly only the wide-angle end which has barrel distortion, but as you zoom in, it disappears, so you have to look at which focal length you use the lens.

best is to look on web sites (photozone.de,  the digital picture) and others, to see what distortion you get.

I’m considering Canon’s EF 35mm f/2 IS USM because I may shoot videos hand-held, and I’d like to have the IS. (I'll be using a crop sensor camera - 70D) But mostly I’d be taking stills.

STM lenses would be even better if you want to use the automatic focus.

35mm qualifies as a wide angle lens on a FF; on a crop sensor camera, however, am I mistaken in thinking that, because the crop sensor is essentially recording what’s in the middle of the lens, any obvious barrel distortion at the peripheral wouldn’t register on the crop sensor? (I’m referring to stills)

it depends on the nature of the distortion, if it is complex, such as a moustache distortion (e.g. Samyang 14mm), cropping will remove some of the worst effects.

However, if the barrel distortion is a very regular curve, then cropping will only remove it partially.

Anyhow, I like the idea of backing away a distance and taking crops in post. For gathering information that is. Any suggestions will be much appreciated! Thanks!

just check how much resolution you need in the end.