[wim]

[quote name='nandadevieast' timestamp='1328981365' post='15803']

Hi Popo,

Supposing the DOF of 85 1.4 on ca crop camera and 135 2 on a FF camera is roughly same...what effect the subject distance will have on it?

Is the DOF same for the equal distance or the same frame?



[/quote]

That would be the same, because the equivalent AoV is the same. That implies the same distance and the same framing.



IOW, with an equivalent FL, which provides the same AoV, on the crop camera one would have the same DoF as with the FF camera, at an aperture on crop equal to the FF aperture divided by the crop factor. If the crop facor is 1.4, to make things simple, a FF camera with a 70 mm lens at F/2 at, e.g., 2 m focusing distance, would have the same DoF as an 1.4 X crop APS-C camera with a 50 mm lens at F/1.4, also at 2 m focusing distance. And both need the same shutterspeed to keep things shake free too <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='' />.



Kind regards, Wim