01-24-2012, 02:26 PM
[quote name='Frank' timestamp='1327329293' post='15165']
Yes, theoretically everything is centered. But I wonder how large is the error in the match between the center of the lens mount on the lens and the center of the lens mount on the camera. For example, for the Nikon DSLR, many lenses shake a little bit after they are mounted as many people have claimed. This kind of shake would cause a shift of the lens center from the sensor center, but I have no idea how large the shift could be, 0.01mm, 0.1mm, or 0.2mm?
Regards
Frank
[/quote]
Yes, quite true. Some - not all - of my EOS mount lenses can shift a bit back and forth. E.g. the Samyang 8mm.
Another variable is - how well is the sensor in the body centered with respect to the mount. I have often seen the statements that a sensor has so many megapixels, and then there is the effective megapixels. For example the Canon 600D has 5184 x 3456 - 17915904 pixels = 18.0 effective Megapixels. But the sensor has 18.7
megapixels. So, I could have almost 50 pixels extra around the edge of the image on all sides that are not used. Is this used to center the sensor with respect to the mount electronically in software? I.e. if the mount is a bit to the left, just use a few columns more on the left side?
Yes, theoretically everything is centered. But I wonder how large is the error in the match between the center of the lens mount on the lens and the center of the lens mount on the camera. For example, for the Nikon DSLR, many lenses shake a little bit after they are mounted as many people have claimed. This kind of shake would cause a shift of the lens center from the sensor center, but I have no idea how large the shift could be, 0.01mm, 0.1mm, or 0.2mm?
Regards
Frank
[/quote]
Yes, quite true. Some - not all - of my EOS mount lenses can shift a bit back and forth. E.g. the Samyang 8mm.
Another variable is - how well is the sensor in the body centered with respect to the mount. I have often seen the statements that a sensor has so many megapixels, and then there is the effective megapixels. For example the Canon 600D has 5184 x 3456 - 17915904 pixels = 18.0 effective Megapixels. But the sensor has 18.7
megapixels. So, I could have almost 50 pixels extra around the edge of the image on all sides that are not used. Is this used to center the sensor with respect to the mount electronically in software? I.e. if the mount is a bit to the left, just use a few columns more on the left side?