12-03-2010, 08:34 AM
[quote name='genotypewriter' timestamp='1291349452' post='4722']
PF is a really weird thing... it's both lens and sensor related. I say lens related because well-corrected lenses (e.g. 125 f/2.5 APO-Lanthar, 200 f2L IS, 200/4 Micro-Nikkor and I'm sure the 60 f/4 UV-VIS-IR too) don't show it. But it is also a sensor related thing because lenses like the 85 1.2L wide open [url="http://www.flickr.com/photos/genotypewriter/4635819634"]show it on digital[/url] but [url="http://www.flickr.com/photos/genotypewriter/4495611132/"]not on film[/url].
I think calling it CA is fairly wrong because CA is caused by refraction of light of different wavelengths. But when light is passing through the center of a lens, there's no refraction so there can't be CA but you can often see [url="http://www.flickr.com/photos/genotypewriter/4635819634/sizes/o"]PF in the center[/url]. Similarly I haven't seen PF getting worse towards the corners like CA typically does.[/quote]
I thought PF was LoCA. At least in the specific case of the Canon 85mm f/1.8, which shocked me how strong it was when I first got it. It looks fine until you hit a highlight. Any bright spot and bang, purple or green fringes depending on if it is behind or in front of the focal plane.
It also fits that true APO lenses wouldn't suffer from it. I don't have experience on film to make any claim there though.
I don't want to put words in your mouth, but that reads as you found indication confirming DxO's claims. Of course I'll wait and see the full report.
PF is a really weird thing... it's both lens and sensor related. I say lens related because well-corrected lenses (e.g. 125 f/2.5 APO-Lanthar, 200 f2L IS, 200/4 Micro-Nikkor and I'm sure the 60 f/4 UV-VIS-IR too) don't show it. But it is also a sensor related thing because lenses like the 85 1.2L wide open [url="http://www.flickr.com/photos/genotypewriter/4635819634"]show it on digital[/url] but [url="http://www.flickr.com/photos/genotypewriter/4495611132/"]not on film[/url].
I think calling it CA is fairly wrong because CA is caused by refraction of light of different wavelengths. But when light is passing through the center of a lens, there's no refraction so there can't be CA but you can often see [url="http://www.flickr.com/photos/genotypewriter/4635819634/sizes/o"]PF in the center[/url]. Similarly I haven't seen PF getting worse towards the corners like CA typically does.[/quote]
I thought PF was LoCA. At least in the specific case of the Canon 85mm f/1.8, which shocked me how strong it was when I first got it. It looks fine until you hit a highlight. Any bright spot and bang, purple or green fringes depending on if it is behind or in front of the focal plane.
It also fits that true APO lenses wouldn't suffer from it. I don't have experience on film to make any claim there though.
Quote:I just did earlier this morning before turning up to work... hmm the early findings are a bit shocking and not in favour of us DxO-skeptics <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/sad.gif' class='bbc_emoticon' alt='' /> I'm going to do a thorough test and upload an article within the next few days, hopefully.
I don't want to put words in your mouth, but that reads as you found indication confirming DxO's claims. Of course I'll wait and see the full report.
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.