Focal Distance: furthest possible maintaining blurred BG

[RobT]

I thought about making a new topic for this question, but its very relevant to whats going on here.

Is compression based on focal length constant per lens or does it change based on sensor size?

For example, would an 85mm lens on a crop body visually maintain the same compression when put on a FF camera even though the focal length would appear shorter?

[dr croubie]

For example, would an 85mm lens on a crop body visually maintain the same compression when put on a FF camera even though the focal length would appear shorter?

a) If you take a head-shot photo with 85mm on aps-c, then swap the lens to an FF body and take the same photo from the same spot, you'll get a wider field of view and the head will be smaller within the frame. Then if you crop the second photo, you'll end up with *exactly* the same photo as the aps-c (except less MP).

b) If you take a head-shot photo with 85mm on aps-c, then swap the lens to an FF body and move closer so the head is the same size in the frame, then perspective will change and you'll get more 'wide-angle' or less 'compression' or whatever you want to call it.

[RobT]

Thank you!

That answers my question exactly.