07-29-2010, 11:56 AM
(This post was last modified: 07-29-2010, 11:57 AM by Brightcolours.)
[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]
It does NOT matter with which sensor Klaus/photozone.de tests the lenses. If lens A shows larger vignetting, more CA and less resolution than lens B on a 10mp Canon EOS 40D, the same will apply when you put lens A and B on a 18mp Canon EOS 7D.
Of course, the resolution figures will both be higher, but resolution figures on their own are rather useless, you compare them with other lenses.
You can verify this with the Canon ESO 350D (8mp) tests and the later Canon EOS 50D (15mp) tests.
So, no need for photozone to not use normal DSLRs to test how lenses compare... Less sharp lenses will be less sharp, no matter which DSLR model you use.
If you have trouble figuring out if a Canon 70-200 f4 L IS USM is sharp on your 550D (18mp) while Klaus showed it to be exceptionally sharp on a 350D (8mp) and 50D (15mp), then how will results from a fictive sensor help you determine that?
I basically think you are trying to find a solution to a problem that does not exist..
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]
It does NOT matter with which sensor Klaus/photozone.de tests the lenses. If lens A shows larger vignetting, more CA and less resolution than lens B on a 10mp Canon EOS 40D, the same will apply when you put lens A and B on a 18mp Canon EOS 7D.
Of course, the resolution figures will both be higher, but resolution figures on their own are rather useless, you compare them with other lenses.
You can verify this with the Canon ESO 350D (8mp) tests and the later Canon EOS 50D (15mp) tests.
So, no need for photozone to not use normal DSLRs to test how lenses compare... Less sharp lenses will be less sharp, no matter which DSLR model you use.
If you have trouble figuring out if a Canon 70-200 f4 L IS USM is sharp on your 550D (18mp) while Klaus showed it to be exceptionally sharp on a 350D (8mp) and 50D (15mp), then how will results from a fictive sensor help you determine that?
I basically think you are trying to find a solution to a problem that does not exist..