« on: April 22, 2013, 12:59:08 PM »
... I never quite understood why people say that FF and APS-C have different DoF (provided the same optics, aperture, and distance to the object are used).
Marketing through misinformation, obfuscation, leading and derogation.
DoF is related to angle of view and aperture. To get the same angle of view at the same distance from the subject, on FF you need a longer focal length (1.6x if we consider a Canon APSC) than on crop.
Then, because f/stops are related to focal length, if you keep the same aperture on both systems you'll see that on crop you end up with a narrower iris. This is why you have more DoF
No it isn't, and this common misunderstanding is why people keep failing to get their heads around this.
Depth of field is a function of two metrics alone, reproduction ratio (how big the subject is projected onto the capturing device) and aperture. Now if you want to make comparisons across sensor sizes you have to make a standard for reproduction size, it doesn't matter what the standard is, but if you don't you can't make relevant comparisons.
"DOF is determined by subject magnification at the film / sensor plane and the selected lens aperture or f-number." http://en.wikipedia.org/wiki/Depth_of_field
I would strongly suggest people stop talking crap and start reading and learning something authoritative about the subjects they seem so intent on teaching other people about.