Luminous Landscape Forum

Raw & Post Processing, Printing => Digital Image Processing => Topic started by: michaelnotar on July 06, 2008, 06:32:37 pm

Title: does CA reduction affect IQ?
Post by: michaelnotar on July 06, 2008, 06:32:37 pm

does chromatic fringing reduction/correction affect image quality negatively...? i know if improves CA obviously, curious to know if there is any side effects?
thanks

Title: does CA reduction affect IQ?
Post by: bill t. on July 06, 2008, 11:00:20 pm

Chromatic is perhaps the most noticeable optical aberration in digital camera systems.  On those occasions when I forget to remove it in ACR, I almost immediately notice it PS.  If its removal introduces other aberrations, the effect does not grab my eye anything like the way chromatic does.  Rainbows are hard to miss.  Whatever the consequences of its removal, those would seem to pale by comparison.

Unscientifically, I have allowed myself to feel that swatting down chromatic also improves image sharpness by re-aligning edges.

And I have never kicked myself for removing chromatic, as I have sometimes done for over sharpening and such.

Title: does CA reduction affect IQ?
Post by: michaelnotar on July 06, 2008, 11:25:44 pm

Quote

Chromatic is perhaps the most noticeable optical aberration in digital camera systems.  On those occasions when I forget to remove it in ACR, I almost immediately notice it PS.  If its removal introduces other aberrations, the effect does not grab my eye anything like the way chromatic does.  Rainbows are hard to miss.  Whatever the consequences of its removal, those would seem to pale by comparison.

Unscientifically, I have allowed myself to feel that swatting down chromatic also improves image sharpness by re-aligning edges.

And I have never kicked myself for removing chromatic, as I have sometimes done for over sharpening and such.
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it certainly makes the images look digital.

Title: does CA reduction affect IQ?
Post by: NikoJorj on July 07, 2008, 06:28:48 am

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does chromatic fringing reduction/correction affect image quality negatively...?
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[a href=\"http://www.vanwalree.com/optics/chromatic.html]Transverse CA[/url] removal consists of solely realigning the 3 channels : it just can improve sharpness, if well made.

Fringing suppression by desaturation of high-contrast contour (eg with the "defringe" tool in LR) has much more side effect imho.