I've got one question unrelated to the lens, regarding the comment that, given the crop factor on a non-FF body, "the 70mm range effectively results in 112mm making it a ideal portrait lens".
I've seen comments in this vein in many places online, and I don't understand them; how is it more of a portrait lens on a 60D than a 5D MkII? Is it just because it gives you a further working distance from your subject? Because that's the only benefit I see...
I understand the definition of a good portrait lens to include such aspects as compression/distortion and background blur in addition to the field of view, but when using the same lens on a 60D as compared to a 5D MkII, we get: Compression/Distortion
: this doesn't change between bodies, so it's still 70mm, not 112mm. Background blur
: for the same composition, a 60D requires a further distance from subject, increasing DOF = decreasing background blur at the same aperture. This makes it less
of a portrait lens, no? Field of view
: for the same composition, a 60D requires a further distance from subject; in isolation (i.e. not considering effect on DOF) this may be good, as the subject is likely to be somewhat less self-conscious.
I'm not wanting to be controversial; this is a question I've long harbored and for which I have yet to find a satisfactory answer, so confirmation or correction of my stated understanding is welcomed.