Hello. I have a simple question - if I take a shot with the 35L on a 5dMk2 at 21MP and crop it to 12.8 MP - what perspective would that approximate on the 5D? Is there an easy way to do the math? I was thinking of using a 35L on the 5dMk2 and was thinking if that could approximate at least a 50mm on the 5D with cropping (keeping DOF/bokeh/etc. out of the equation). Thanks.

TEJ PHATAKwrote:Hello. I have a simple question - if I take a shot with the 35L on a 5dMk2 at 21MP and crop it to 12.8 MP - what perspective would that approximate on the 5D? Is there an easy way to do the math? I was thinking of using a 35L on the 5dMk2 and was thinking if that could approximate at least a 50mm on the 5D with cropping (keeping DOF/bokeh/etc. out of the equation).Why would you be concerned with getting an exact megapixel count from a camera rather than just taking pictures with it and employing proper framing and, possibly, cropping?

Just guessing but I'd say a 35mm on a 5D2 is like a 45mm on a 5D.12.8/21 = .6095.6095^-2 = .7807235mm / .78072 = 44.83mmNow that I look at that I think I'm way wrong. Skip this.

Actually, i'd agree with you. To get a 12.8mp sensor off of a 21mp sensor that's 36x24mm (while keeping the 3:2 proportion) you'd need a sensor that's 28.1x18.7mm roughly. That would make the original sensor 1.28 times larger, giving you an effective 1.28x croping factor. Meaning a 35mm lense would be roughly 44.84mm perspective equivalent if you croped 12.8mp out of the center of your image.

Thanks for the replies!