07-29-2010, 11:50 AM
[quote name='Kozuch' timestamp='1280403014' post='1380']
Well, of course a profi lab would be very expensive... but as a Czech I try to think about an affordable workaround of this issue... <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' /> I can imagine it can not be that difficult to create a simple true optical resolution test at home?
Probably, the only thing that would need some more effort is how to evaluate the results, maybe one could capture the projection of reference image with another digital camera (glue more photos together so we are sure this action does not limit the resolution test) and then have a software count these lines, as I can imagine no one wants to count 2000 lines by hand...
I am sure this set-up is doable and could produce nearly proffesional results. It is only a question of will. I really appreciate your current tests, but this is just an idea on how to make it better.
Regarding the usability of lab results for concrete sensor - I did not really understand what you meant by this. Do you mean maybe the ability of a sensor to reach a certain resolution?
[/quote]
Oh, it's certainly possible to assemble an optical MTF lab "by hand". However, reliability and speed of analysis have to be taken into account.
If we ever consider moving this way we'd certainly go for a Zeiss lab and ... this simply costs a fortune. Regarding the current site revenues this is simply prohibitive.
Regarding the sensor as base for testing - have you noticed in our tests that very few lenses are actually capable of outresolving today's sensors at image portions other than the center ? Moving to an optical MTF test seems like looking for a problem that does not exist.
Beyond 10mp (APS-C) and 20mp (full format) an camera upgrade has more to do with "political correctness" rather than sense.
There're a few dependencies of an image sensor. Vignetting comes into mind first of course. Purple fringing is another one. AA filter side effects.
And if you think that an optical MTF test is the way to go ... well, go for it .. :-)
Well, of course a profi lab would be very expensive... but as a Czech I try to think about an affordable workaround of this issue... <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='
' /> I can imagine it can not be that difficult to create a simple true optical resolution test at home?Probably, the only thing that would need some more effort is how to evaluate the results, maybe one could capture the projection of reference image with another digital camera (glue more photos together so we are sure this action does not limit the resolution test) and then have a software count these lines, as I can imagine no one wants to count 2000 lines by hand...
I am sure this set-up is doable and could produce nearly proffesional results. It is only a question of will. I really appreciate your current tests, but this is just an idea on how to make it better.
Regarding the usability of lab results for concrete sensor - I did not really understand what you meant by this. Do you mean maybe the ability of a sensor to reach a certain resolution?
[/quote]
Oh, it's certainly possible to assemble an optical MTF lab "by hand". However, reliability and speed of analysis have to be taken into account.
If we ever consider moving this way we'd certainly go for a Zeiss lab and ... this simply costs a fortune. Regarding the current site revenues this is simply prohibitive.
Regarding the sensor as base for testing - have you noticed in our tests that very few lenses are actually capable of outresolving today's sensors at image portions other than the center ? Moving to an optical MTF test seems like looking for a problem that does not exist.
Beyond 10mp (APS-C) and 20mp (full format) an camera upgrade has more to do with "political correctness" rather than sense.
There're a few dependencies of an image sensor. Vignetting comes into mind first of course. Purple fringing is another one. AA filter side effects.
And if you think that an optical MTF test is the way to go ... well, go for it .. :-)