Distortion

So from what I can tell, distortion is more of a problem when you stand close to something, not necessarily the focal length of the lens. Maybe I'm wrong?

Obviously the longer the focal length the further back you have to stand to get everything in the picture.

If so, are there any rules or guidelines for how far to stand away from something to avoid distortion? Like the 1/focal length, only for minimizing distortion. 5 feet, 10 feet, 15 feet or whatever distance.

I would say 10' is about the minimum distance regardless of the focal length.

It isn't so simple.

It also depends on the field of view of the subject as you see it in real life, compared to the field of view as you see it in print.

If you see a human face life-size in print, you expect to see the same distortion as if a real person had stood at the same distance.

So if you use a wide-angle lens and goes much closer and take the shot then you wonder about the big nose in the print.

If you stand very close to someone, then you see a very large face and your brain knows that you are close. So the brain doesn't think it's strange that the nose is larger.

In the end, a crop of a photo from a wide lens will have the same amount of perspective distortion than a photo taken from the same distance with a longer lens. So if you stand two meters from someone and take one shot with a 10mm lens and one shot with a 200mm lens and you then crop the 10mm shot and print two faces of the same size, you end up with identical prints - except for the uncropped print from the 200mm lens having better quality.

delta0014 wrote in post #17042503
If so, are there any rules or guidelines for how far to stand away from something to avoid distortion? Like the 1/focal length, only for minimizing distortion. 5 feet, 10 feet, 15 feet or whatever distance.

There are no simple rules for perspective (relative sizes of objects at different distances from the eye or camera) control because the subject can vary a lot. For ordinary portraiture of a single person, keeping the camera six to ten feet from the subject will generally improve the perspective of the face. However, there are other issues when photographing buildings, and any distance rules for portraiture would not apply.

SkipD wrote in post #17045229
There are no simple rules for perspective (relative sizes of objects at different distances from the eye or camera) control because the subject can vary a lot. For ordinary portraiture of a single person, keeping the camera six to ten feet from the subject will generally improve the perspective of the face. However, there are other issues when photographing buildings, and any distance rules for portraiture would not apply.

There are even rules for how to aim the camera. Using a wider lens and pointing it straight ahead or pointing it a bit upwards (to get the top of high buildings) makes a big difference - as soon as the lens is aimed upwards, all the originally perfectly vertical lines will point inwards and the top of the buildings will look much smaller than the lower parts. And that's one of the reasons why this world got blessed with special tilt-shift lenses.