02-25-2011, 01:19 PM
(This post was last modified: 02-25-2011, 01:37 PM by Brightcolours.)
[quote name='AT75' timestamp='1298616211' post='6345']
I've made a small test to check, if the Raw Developer shows more CAs on the same file, than the ACR
And see no significant difference to speak of.
So, if we have the same lens, same shooting distance, same testchart, (also same lightning, I hope?) and same Imatest version, it is unlikely to find twice as much CAs between these 2 different RAW converters (as we see sometimes in the tests of ZF lenses). So, if the conditions are the same between your shots and Klaus', it really could be a sort of sensor difference.
If they are not the same... I think there should be some more unity in the measurements <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />)))
[/quote]
You must have littel understanding of LaCA, if you think the sensor or its microlenses can affect the amount. The D3x has a vertical resolution of 4032 pixels, the 5D mk II has a vertical resolution of 3744 pixels.
The resolution of the sensors is the only thing that can influence the LoCA measurements (if done correctly).
The D3x should have a higher CA value with the same lens of 100 / 3744 * 4032 = 108%.
It is impossible for microlenses to make for instance the whole red projection bigger (that is what LaCA is about, it is measuring how the different colours or wavelengths of light get bent more or less through the optics of the camera's lens, producing some colours to have a bigger or smaller image projected onto the sensor). Microlenses can only affect the pixel they reside above, they can NOT direct light of only a certain wavelength uniformly to neighbouring pixels.
Even a difference of AA filter strength should not affect CA measurements. Most probably, the software doing the measuring is not very reliable / not very good at it / not really measuring CA as we know it.
I've made a small test to check, if the Raw Developer shows more CAs on the same file, than the ACR
And see no significant difference to speak of.
So, if we have the same lens, same shooting distance, same testchart, (also same lightning, I hope?) and same Imatest version, it is unlikely to find twice as much CAs between these 2 different RAW converters (as we see sometimes in the tests of ZF lenses). So, if the conditions are the same between your shots and Klaus', it really could be a sort of sensor difference.
If they are not the same... I think there should be some more unity in the measurements <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='
' />)))[/quote]
You must have littel understanding of LaCA, if you think the sensor or its microlenses can affect the amount. The D3x has a vertical resolution of 4032 pixels, the 5D mk II has a vertical resolution of 3744 pixels.
The resolution of the sensors is the only thing that can influence the LoCA measurements (if done correctly).
The D3x should have a higher CA value with the same lens of 100 / 3744 * 4032 = 108%.
It is impossible for microlenses to make for instance the whole red projection bigger (that is what LaCA is about, it is measuring how the different colours or wavelengths of light get bent more or less through the optics of the camera's lens, producing some colours to have a bigger or smaller image projected onto the sensor). Microlenses can only affect the pixel they reside above, they can NOT direct light of only a certain wavelength uniformly to neighbouring pixels.
Even a difference of AA filter strength should not affect CA measurements. Most probably, the software doing the measuring is not very reliable / not very good at it / not really measuring CA as we know it.