olyacme wrote:
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Longitudinal CA shows up in the focal plane all the time.
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Not true. LoCA may or may not show up in the focal plane. That depends on lens design and aperture. This does not lead to purple fringing. If what you said is true, then there should also be green and red fringing as well depending on the lens. sensor bloom is always purple fringing, not?
makron wrote:
Not true. LoCA may or may not show up in the focal plane. That depends on lens design and aperture. This does not lead to purple fringing. If what you said is true, then there should also be green and red fringing as well depending on the lens. sensor bloom is always purple fringing, not?
By "all the time" I mean frequently. i.e., many lenses suffer from Longitudinal CA, and that those that do are largely responsible for the so called "Purple Fringing" effect. There is no rule that says that violet must be the most poorly corrected colour, however. Blue or red fringings are also common.
Hi,
I just updated the Index and wonder if you can elaborate a little on this lens. It just says "Cosina 55/1.2" on it? The bright rings around the background OOF highlights (my personal obsession) seem less than usual from Cosina (the Voigtländer 58mm for example).
Hi fotissgr,
Your 50mm Minolta MD Rokkor images look OK. If you really asked, that is...
The fence images, are they sharpened for the web or "unprocessed"?
Jonas B wrote:
Hi,
I just updated the Index and wonder if you can elaborate a little on this lens. It just says "Cosina 55/1.2" on it? The bright rings around the background OOF highlights (my personal obsession) seem less than usual from Cosina (the Voigtländer 58mm for example).
It is older than the CV 58/1.4 and an unrelated design. I believe that it is essentially the same as the Tomioka 55/1.2 except made by Cosina and multi-coated. It is in the Pentax K mount and has a 9-blade aperture.
I've only just started to play around with lens, but here are a few preliminary comments. Compared to the CV 58/1.4 (which I also have) it has a nicer bokeh (which you suggest), but is noticeably more flare prone. This lens should not be used with out a hood. It appears to be reasonably sharp wide open (that is, within expectations).
