lens perspective and 1.6x focal multiplier

[darrelchia]

I think perhaps the question is too vaguely worded. The term "perspective" means different things to different people.

To me, i'd say because of the optics of the lens, it would be different. A 50mm lens would have a different compression as opposed to a 90mm.

The dpreview post interprets "perspective" more to the depth, distance, but does not bring into consideration the optics of the lenses.

I dunno if i'm right to say this, but if you factor in the optics of the lenses, the image would appear different. Consider the using a 17.5mm with a 1.6x crop as against a 28mm full frame, i would imagine the 17.5mm would show distortion, while the 28mm would appear more compressed.

 

[Jed]

Ah yes. So Marc, if, for instance, you get an 85mm perspective whether you have a 2x crop or a 4x crop, why is that a reason to prefer a film cam? The gist of my argument was, ok, so maybe you don't get a different perspective, you still get the same perspective, but *why does it matter*? Ultimately you compose with what you see through the viewfinder using the camera and lens combination that's in your hands. There's no holy grail that says that 135 format perspective is best. Or is there? If there is, why?

Second, you have a 2x crop for instance, with you 85mm lens. Which means you'll stand further away from your subject, which again compensates for the difference in perspective when you crop back.

Darrel, I'm not sure what you refer to by the term distortion, but if you mean wide angle distortion, then think about it this way. Yes a 17.5mm starts with inherently more wide angle perspective distortion. But where is this distortion most obvious? Around the edges. Which portion do you crop out with your crop factor? The edges... Furthermore the 17.5mm would need to be used further back with the crop factor, which means you end up with less entailing wide angle distortion around the edges.

Ultimately subject to camera distance is crucial in determining perspective, and with a crop factor, you naturally step back, restoring the "compression". And again the same question as above holds true. So maybe you get a different perspective/compression, but *why does it matter*? Ultimately you compose with what you see through the viewfinder using the camera and lens combination that's in your hands. There's no holy grail that says that 135 format perspective is best. Or is there? If there is, why?

And remember that for anything you might lose at one end of the scale, you gain at the other. For instance, and this is slightly OT, you lose the ability to isolate DOF as well as with a larger format, but don't forget that you also gain the ability to get more front to back sharpness with the smaller format.

 

[MooEy]

i choosed 135mm perspective. simple, when a 85mm lens is used at 135mm with the 1.5x crop factor, everything changes. u will no longer stand at the same distance to ur subject. distance from lens to the subject is the main thing that creates the perspective.

sure, lots of website will tell u to imagine shooting a photo on a 35mm film and cropping it, then go and prove that no prespective is being changed due to the crop factor. but in actual use, u no longer stand at the same place, u will move back, thus u will get the perspective of a 135mm lens.

~MooEy~

 

[BurgaFlippinMan]

sure, lots of website will tell u to imagine shooting a photo on a 35mm film and cropping it, then go and prove that no prespective is being changed due to the crop factor.

which is true, perspective is not affected by focal length or cropping in anyway. It is the subject to lens distance that does it. a WA lens does not distort perspective any more than a telephoto.