01-07-2011, 04:45 PM
[quote name='genotypewriter' timestamp='1294403200' post='5378']
Whoa there... hang on a sec. The 70-210 is no real APO lens... people kill for real APO lenses.
[/quote]
Well of course you are right. The correct thing to say about the old Tokina 70-210 is that it does not show any noticeable in-focus purple-fringing/lateral color on Sony Nex raw images. At a few small (but not too small) apertures. At portrait distances.
There is plenty of color fringing wider than F8, or even wider than F16 at the long end of the zoom. The color fringing "aperture sweet spots" remind me of zoom distortion sweet spots, where below a certain focal length you have barrel distortion, above the sweet spot you have pincushion, but there's one place where things are pretty rectilinear.
Further supporting your point, have not done any testing of the Tokina for the longitudinal chromatic aberration that Photozone has so thoroughly explained.
Yes, and of course now you are making me think of a way to compare an APS-C image corner from my 70-210 SD II zoom with one from the Coastal Optic 60mm. Beware, Jena Optical.
However to argue with you, would point out that you are implying an unrealistically high bar for calling a lens apochromatic. The Coastal optic lens has virtually no color error (or sharpness imperfections) even at infrared and ultraviolet wavelengths. Such effectively invisible wavelengths can surely be said to be of little interest to for example the vast majority of readers (you know who you 3 people in the world are) of this forum. And let's at least agree to call a lens "essentially apochromatic" if it doesn't show any in-focus fringes or out-of-focus longitudinal color shifts in the _visible_ spectrum. Essentially apo, even if the lens does not have quite the resolution of the Coastal Optic.
For example would say it's fair to call the Voigtlander SL 125mm F2.5 APO Lanthar essentially apochromatic, even though it has not quite the zero color/etc aberrations of the Coastal Optic 60mm.
You didn't, I had mixed you up with someone else's comments about anti-aliasing filters. You were simply complaining about the negative effects of (even raw file) ***noise reduction*** on effective Nex sensor resolution. Which hasn't bothered me too much (in fact I see plenty of fixable noise in my Nex ISO 800 images), but then my clients aren't demanding enough to make me go out and buy a Canon 200mm F2 lens, either.
By the way, where did I ever mention that seeing single-pixel details is the ***definition*** of a lens being apochromatic? My comment was only intended to imply that a lens being apochromatic ***helps*** it resolve single-pixel details. Hmm, interesting how the cold medium of web posts makes all thoughts and disagreements sound harsher than they really are.
Whoa there... hang on a sec. The 70-210 is no real APO lens... people kill for real APO lenses.
[/quote]
Well of course you are right. The correct thing to say about the old Tokina 70-210 is that it does not show any noticeable in-focus purple-fringing/lateral color on Sony Nex raw images. At a few small (but not too small) apertures. At portrait distances.
There is plenty of color fringing wider than F8, or even wider than F16 at the long end of the zoom. The color fringing "aperture sweet spots" remind me of zoom distortion sweet spots, where below a certain focal length you have barrel distortion, above the sweet spot you have pincushion, but there's one place where things are pretty rectilinear.
Further supporting your point, have not done any testing of the Tokina for the longitudinal chromatic aberration that Photozone has so thoroughly explained.
Quote:Just because you can see 1-pixel details it doesn't mean the lens is APO. Here's a real APO lens:
http://www.jenoptik-inc.com/coastalopt-s...u-155.html
Yes, and of course now you are making me think of a way to compare an APS-C image corner from my 70-210 SD II zoom with one from the Coastal Optic 60mm. Beware, Jena Optical.
However to argue with you, would point out that you are implying an unrealistically high bar for calling a lens apochromatic. The Coastal optic lens has virtually no color error (or sharpness imperfections) even at infrared and ultraviolet wavelengths. Such effectively invisible wavelengths can surely be said to be of little interest to for example the vast majority of readers (you know who you 3 people in the world are) of this forum. And let's at least agree to call a lens "essentially apochromatic" if it doesn't show any in-focus fringes or out-of-focus longitudinal color shifts in the _visible_ spectrum. Essentially apo, even if the lens does not have quite the resolution of the Coastal Optic.
For example would say it's fair to call the Voigtlander SL 125mm F2.5 APO Lanthar essentially apochromatic, even though it has not quite the zero color/etc aberrations of the Coastal Optic 60mm.
Quote:Oh btw... Where did I ever mention anything about an AA filter here? <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='' />
You didn't, I had mixed you up with someone else's comments about anti-aliasing filters. You were simply complaining about the negative effects of (even raw file) ***noise reduction*** on effective Nex sensor resolution. Which hasn't bothered me too much (in fact I see plenty of fixable noise in my Nex ISO 800 images), but then my clients aren't demanding enough to make me go out and buy a Canon 200mm F2 lens, either.
By the way, where did I ever mention that seeing single-pixel details is the ***definition*** of a lens being apochromatic? My comment was only intended to imply that a lens being apochromatic ***helps*** it resolve single-pixel details. Hmm, interesting how the cold medium of web posts makes all thoughts and disagreements sound harsher than they really are.