d.s. Posted October 23, 2018 Share #1 Posted October 23, 2018 Advertisement (gone after registration) Hi. I'm wondering what 50mm f/1.5 or faster lenses (M or LTM) have very little field curvature wide open in the 2 to 5m range. Thanks. Quote Link to post Share on other sites More sharing options...
Advertisement Posted October 23, 2018 Posted October 23, 2018 Hi d.s., Take a look here Fast and Flat 50s. I'm sure you'll find what you were looking for!
tobey bilek Posted October 23, 2018 Share #2 Posted October 23, 2018 no experience except to offer you focus 1/3 the way from center to corner. Perhaps someone with .095 50 mm could help. Where would you use such settings? Copy work and low light landscape, use a tripod. Portraits with subject off center, use live view and color fringing to indicate sharp focus. Quote Link to post Share on other sites More sharing options...
a.noctilux Posted October 23, 2018 Share #3 Posted October 23, 2018 (edited) In my experience ... The best lens for flat field in the 2-5m range is Summilux-M 1.4/50mm asph. Very handy for brick wall ☺️...lens test . Seriously, I took pictures of posters 3m x 4m and I can rely on 80% of field to be sharp enough. But in these cases, I close the Lux to f/2.8 - 4 in dark places and more ISO when possible or some supports 😇. Even with this one, only reliable to about 70 to 80% of whole field when used wide open. Leica M lenses are created with 3D subjects in mild, I think that "fast and flat field wide open" would be hard to find. In Leica R lenses, you may find macro lenses (but only f/2.8 like Macro-Elmarit-R 60mm or 100mm Apo-Macro-Elmarit-R) flatter field (in my experience of real use, not brick wall test). Edited October 23, 2018 by a.noctilux Quote Link to post Share on other sites More sharing options...
d.s. Posted October 23, 2018 Author Share #4 Posted October 23, 2018 Good point on the 1/3 of the way remark, Tobey. A, I'm a bit surprised by your recommendation of the Summilux. I seem to recall Puts, et. al. suggesting otherwise. But yes, I intend on photographing artfully lit brick walls at night. The more planar of a fast lens the better. I think the f/1.1 Nokton is a planar design. Its f/1.5 variant, and the C-Sonnar appear to be out. Quote Link to post Share on other sites More sharing options...
lct Posted October 23, 2018 Share #5 Posted October 23, 2018 Among my own lenses (M 50/1.4 v2, v3 & asph, M 50/2 v4, v5 & apo, ZM 50/1.5), the only one having a flat field curvature at f/2 is the 50/2 apo. Quote Link to post Share on other sites More sharing options...
d.s. Posted October 23, 2018 Author Share #6 Posted October 23, 2018 Perhaps I'll reconsider the Summilux. LCT, the v3 is the pre-asph that focuses to .7m, right? Have you noticed any difference in field curvature between it and the asph? Quote Link to post Share on other sites More sharing options...
lct Posted October 23, 2018 Share #7 Posted October 23, 2018 (edited) Advertisement (gone after registration) Yes and no sorry because my only comparos re field curvature were between 50/2 apo and 50/1.4 asph. Now suffice it to compare Leica's MTF graphs (attached) to suspect that the asph is better than v3 from this viewpoint.LeicaM_5014_asph_tech_p03.pdfLeicaM_5014_v3_tech_p03.pdf Edited October 23, 2018 by lct Quote Link to post Share on other sites More sharing options...
astrostl Posted October 23, 2018 Share #8 Posted October 23, 2018 50/2 APO. See https://diglloyd.com/prem/prot/LEICA/LeicaM/lens-Leica50f2-APO-ASPH-compare-bristlecone.html for comparisons (inc. the Summilux-M) Quote Link to post Share on other sites More sharing options...
d.s. Posted October 23, 2018 Author Share #9 Posted October 23, 2018 While I understand the APO as being a benchmark, I'm not considering f/2.0 lenses. The data sheets were indeed informative, LCT. Though the measurements were taken at infinity, I assume they're also indicative of medium distance performance as well. Quote Link to post Share on other sites More sharing options...
lct Posted October 23, 2018 Share #10 Posted October 23, 2018 At all subject distances, M 50/1.4 v2 & v3 are soft at edges and corners below f/4. M 50/1.4 asph is sharper but remains rather soft there at f/1.4 and to a lesser extent f/2. Now i have never seen an f/1.4 or f/1.5 lens with flat field curvature at wide aperture so far. Not ideal apertures to shoot brick walls if you ask me. 😉 1 Quote Link to post Share on other sites More sharing options...
d.s. Posted October 23, 2018 Author Share #11 Posted October 23, 2018 I've never seen one either. I wonder how small Peter Karbe could make it. Quote Link to post Share on other sites More sharing options...
astrostl Posted October 24, 2018 Share #12 Posted October 24, 2018 (edited) 4 hours ago, lct said: Not ideal apertures to shoot brick walls if you ask me. 😉 So d.s. what is the actual shooting use-case that requires a close-range flat field and f/1.5 or faster aperture? Edited October 24, 2018 by astrostl Quote Link to post Share on other sites More sharing options...
d.s. Posted October 24, 2018 Author Share #13 Posted October 24, 2018 Astrostl, It's mostly for dimly lit facaded in low light. Quote Link to post Share on other sites More sharing options...
d.s. Posted October 24, 2018 Author Share #14 Posted October 24, 2018 I like small lenses. How bad is an f/1.5 optimized C-Sonnar at medium distances? Quote Link to post Share on other sites More sharing options...
lct Posted October 24, 2018 Share #15 Posted October 24, 2018 16 minutes ago, d.s. said: I like small lenses. How bad is an f/1.5 optimized C-Sonnar at medium distances? Great lens. My favorite 50 for portraits but i don't use it on rangefinders as it suffers from focus shift a lot. My sample is optimized at f/1.5 though vs f/2.8 for several others. The latters suffer from focus shift as well but in a different way. Otherwise the lens is nicely soft at f/1.5, ideal for forgiving portraits, and plenty sharp at f/4 and on. It is not prone to flare at all. I would forget the idea of flat focus field below f/5.6 though. Quote Link to post Share on other sites More sharing options...
d.s. Posted October 24, 2018 Author Share #16 Posted October 24, 2018 (edited) I assume the MTFs are based on an f/2.8 optimized version. The chart makes it seem like the softness is gradual, and consistent out to the edges (no sudden mid zone dips). I think that may result in more malleable scans. In 50mm I already have an Elmar-M and ZM Planar. Focus shift isn't a concern. Edited October 24, 2018 by d.s. Quote Link to post Share on other sites More sharing options...
lct Posted October 24, 2018 Share #17 Posted October 24, 2018 33 minutes ago, d.s. said: I assume the MTFs are based on an f/2.8 optimized version. The chart makes it seem like the softness is gradual, and consistent out to the edges (no sudden mid zone dips). I think that may result in more malleable scans. In 50mm I already have an Elmar-M and ZM Planar. Focus shift isn't a concern. I have no MTF graphs for the ZM 50/1.5 but be is optimized for f/1.5 or f/2.8, focus shift remains a concern on rangefinders. Not a bit deal for good RF users but one has to compensate when focusing this lens anyway. No problem when focusing stop down on mirrorless cameras though. BTW Elmar and Planar 50 do not suffer from focus shift AFAIK but i have no experience with the Planar. Quote Link to post Share on other sites More sharing options...
astrostl Posted October 24, 2018 Share #18 Posted October 24, 2018 4 hours ago, d.s. said: Astrostl, It's mostly for dimly lit facaded in low light. With scrutiny on the corners? Quote Link to post Share on other sites More sharing options...
d.s. Posted October 25, 2018 Author Share #19 Posted October 25, 2018 3 hours ago, lct said: I have no MTF graphs for the ZM 50/1.5 but be is optimized for f/1.5 or f/2.8, focus shift remains a concern on rangefinders. Not a bit deal for good RF users but one has to compensate when focusing this lens anyway. No problem when focusing stop down on mirrorless cameras though. BTW Elmar and Planar 50 do not suffer from focus shift AFAIK but i have no experience with the Planar. My point was that I have lenses for brighter conditions (astigmatism in the corners wide open at medium distances is apparent with the Planar; I haven't noticed anything of the sort with the Elmar-M yet). An f/1.5 optimized Sonnar has no focus shift at f/1.5, which is where I would primarily be using it. But yes, focus shift is not difficult to compensate for with some practice. Having the Sonnar optimized for f/1.5, to me, would be preferred. At least then I'm adjusting focus progressively in the same direction. Quote Link to post Share on other sites More sharing options...
d.s. Posted October 25, 2018 Author Share #20 Posted October 25, 2018 1 hour ago, astrostl said: With scrutiny on the corners? No. Across the frame. Quote Link to post Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.