>>4476014>DISTANCE to subject influences distortion, and FOCAL LENGTH influences background compression.Not really. And that's what i'm talking about how people became so ignorant.
Distance tricks perspective. Focal length tricks mere field of view.
Take picture with 28mm, crop the center in 50mm or 100mm or 1000mm and compare with actual 50 or 100 or 1000 lens's picture.
The only difference will be the field of view, how wide or narrow the picture.
In other words, in wide picture there is narrow focal length's 'compression' always. You just have to crop it to make it prominent to notice.
It's like people saying people using umbrellas causes rain.
Same in muh Portrait Lenses.
The real reason why 75~135mm are called PL is because the distance you take with them creates appropriate perspective for portrait.
Then
>Why not just shoot 18mm and crop it to 135?Because of the resolution.
Lastly, there is another micro difference between different focal length lenses. Minimum and Maximum focus distance.
28mm lens has maximum focus distance at 2(or i would say 8) meters
>>4476013. And 135mm it's 20 meters.
Which means with a 135mm lens you can be precise to focus a subject at 10m or a subject at 20m and 28mm can't do the same thing.