11-21-2011, 12:27 PM
When you do not have enough resolution to have sharpness at a certain print size, it does not impact the DOF.
Suppose you have a 6mp camera, and a 48mp camera. Suppose we have a print size that allows the 48mp image to still appear to be sharp, but the 6mp image loses its sharpness due to the big pixels. Does the 6mp image show a different DOF than the 48mp image? No. Just the sharpness at the plane of focus is not there anymore. But exactly the same convergence into blur still occurs.
This separates pixel pitch, and sensor resolution, from the other things that determine DOF (focal length/field of view, aperture, print size and viewing distance). Pixel pitch and resolution determine if there is any perceived sharpness or not, it is on or off. As such it should be viewed separately from DOF, or "which part of the 'depth' of an image still appears relatively in focus".
Again, my post was about Ian's question about what would be equivalent to his 85mm f1.8 lens on FF (he is using a D7000), DOF wise. Not about DOF perception of a certain sized print on a certain view distance. And there all other factors than size of aperture and field of view do not come into the discussion. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/laugh.gif' class='bbc_emoticon' alt=':lol:' />
Suppose you have a 6mp camera, and a 48mp camera. Suppose we have a print size that allows the 48mp image to still appear to be sharp, but the 6mp image loses its sharpness due to the big pixels. Does the 6mp image show a different DOF than the 48mp image? No. Just the sharpness at the plane of focus is not there anymore. But exactly the same convergence into blur still occurs.
This separates pixel pitch, and sensor resolution, from the other things that determine DOF (focal length/field of view, aperture, print size and viewing distance). Pixel pitch and resolution determine if there is any perceived sharpness or not, it is on or off. As such it should be viewed separately from DOF, or "which part of the 'depth' of an image still appears relatively in focus".
Again, my post was about Ian's question about what would be equivalent to his 85mm f1.8 lens on FF (he is using a D7000), DOF wise. Not about DOF perception of a certain sized print on a certain view distance. And there all other factors than size of aperture and field of view do not come into the discussion. <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/laugh.gif' class='bbc_emoticon' alt=':lol:' />