01-21-2012, 03:19 AM
[quote name='wim' timestamp='1327077525' post='15058']
Good question, Frank.
Generally speaking I expect tolerances in this regard to be very, very small, in the order of a few micrometers or less. It has to be, because the effects of this in the sensor plane are really dramatic, as popo actually proved with his post. 15 microns of tilt is too much already <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />. The exact tolerances I don't know, however. And as you know yourself, even with WA lenses, a minute amount of tilt or shift makes quite a difference.
I also expect tolerances in lenses and AF to be quite a bit larger, because those are more difficult to control, due to all the moving parts involved, which means that everything else has to be within as tight as possible tolerances.
Kind regards, Wim
[/quote]
Hi Wim, thank you for your answer. I understand that the tolerance for tilt should be very small, especially when the lens is focused at infinity. But how about the tolerance for the shift? If the optical axis of the lens is off set from the center of the sensor but it is still orthogonal to the sensor plane, then I would expect that at the four corner regions of the sensor the decrease in resolution and the vignetting would be nonsymmetric. How about the tolerance in this case? I expect that the tolerance in this case would be larger than the tolerance in tilt, but I would like to check with you. Does a lens factory control the tolerance in shift as stringently as in tilt?
Regards,
Frank
Good question, Frank.
Generally speaking I expect tolerances in this regard to be very, very small, in the order of a few micrometers or less. It has to be, because the effects of this in the sensor plane are really dramatic, as popo actually proved with his post. 15 microns of tilt is too much already <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' />. The exact tolerances I don't know, however. And as you know yourself, even with WA lenses, a minute amount of tilt or shift makes quite a difference.I also expect tolerances in lenses and AF to be quite a bit larger, because those are more difficult to control, due to all the moving parts involved, which means that everything else has to be within as tight as possible tolerances.
Kind regards, Wim
[/quote]
Hi Wim, thank you for your answer. I understand that the tolerance for tilt should be very small, especially when the lens is focused at infinity. But how about the tolerance for the shift? If the optical axis of the lens is off set from the center of the sensor but it is still orthogonal to the sensor plane, then I would expect that at the four corner regions of the sensor the decrease in resolution and the vignetting would be nonsymmetric. How about the tolerance in this case? I expect that the tolerance in this case would be larger than the tolerance in tilt, but I would like to check with you. Does a lens factory control the tolerance in shift as stringently as in tilt?
Regards,
Frank