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p.5 #5 · p.5 #5 · The Voigtlander Nokton 40mm f/1.2 FE is coming! | |
DavidBM wrote:
Sure it'll likely have a bigger area if sharoness wide open than the c/v 1.4/40. But that thing has basically a tiny dot of central sharpness before it does from modestly soft to very soft. You could double the diameter of wide open sharpness on the 1.4/40 (on Sony) and still not really have a big enough area for flexibility.
I suppose I should clarify what I mean by OK sharpness (which may or may not be what Fred meant). I mean good decent sharpness of the kind you get with a modern lens like the ZA 1.4/35 at its widest aperture.. Fully useaable, but you notice a big improvement as you stop down. I don't mean by OK the hazy thing you get on decent legacy f1.2 lenses. Maybe that's "poor but not useless"?...Show more →
David,
I think you can define sharpness with MTFs quite nicely. Modern Zeiss lenses wide open at f/1/4 typically have about 90%, 80%, and 60% contrast at 10 lp/mm, 20 lp/mm, and 40 lp/mm respectively that extends in a 10mm radius from the centre of the frame. Otus lenses (particularly the 55) are a bit better and the Milvus 50 is just a bit worse, but to me this defines a modern lens. The Leica 28 lux, 35 lux and 50 lux pretty much show this pattern as well but tend to be a little sharper in the very centre (although the 35 FLE isn't) and the performance decreases a bit as it goes out further in the frame.
In contrast to what I would call these modern lenses older lenses like the Leica R 80 f1/4, the Zeiss C/Y 85 f/1.4, the Zeiss C/Y 50 f/1.4 and others wide open at f/1.4 have MTFs pretty close to 80%, 60%, and 30% contrast at 10 lp/mm, 20 lp/mm, and 40 lp/mm respectively and depending on the lens this sometimes even drops a bit as you move away from the centre. These lenses are all noticeably softer than the modern lenses.
It is too bad that Voigtlander doesn't publish MTFs and certainly not measured ones, because then we would know. I would expect this lens to have MTFs with something like 80%, 70%, and 40% contrast at the 10, 20, and 40 lp/mm at best. This is about what the Zeiss ZE/ZF (i.e. Classic) 35 f/1.4 had. It might be a tad worse and this centre sharpness may not extend all the way to make a 10mm radius, but I expect it to be in that league. Not as sharp as modern lenses and not as soft as come of the older lenses that still have have an interesting look wide open.
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