Scola77 Posted February 23, 2011 Share #1 Â Posted February 23, 2011 Advertisement (gone after registration) I cannot find a 50mm summilux anywhere, so I am "slumming it" with a zeiss sonnar. Â Actually it is quite a nice lens. The only issue I have is when shooting wide open, there is a noticeable focus shift. Not too bad, just "soft" at 1.5. At first I thought this was the character of the lens, but when I focused slightly beyond the subject, it was razor sharp! Damnation. Of course now I read that this is a common with the Sonnars and digital M cameras - some have focus shift, others do not. Â Maybe I am being too picky, what do you think? The "soft" look isn't too bad - you can still read words & numbers when shooting signage, etc. It's just not as good as it could be. Â Cheers! Link to post Share on other sites More sharing options...
Advertisement Posted February 23, 2011 Posted February 23, 2011 Hi Scola77, Take a look here Am I being unreasonable? (Zeiss Sonnar focus issue). I'm sure you'll find what you were looking for!
smb Posted February 23, 2011 Share #2 Â Posted February 23, 2011 I use the lens on a film M without problems. I am not using the f1.5 at minimum focal distance. I have used the f1.5 from approximately 15 feet photographing people where id doesn't matter if it is the eyes or nose that is in focus. I particularly like it for B&W. Link to post Share on other sites More sharing options...
Scola77 Posted February 23, 2011 Author Share #3 Â Posted February 23, 2011 SMB - from what I understand these lenses were optimized for film cameras, not digital Ms - which is probably why you are not experiencing this issue (or it is a very limited effect). I still do not know how a lens adjustment for a film camera could be different for a digital one, but apparently that is what the folks at Zeiss say. Link to post Share on other sites More sharing options...
jaapv Posted February 23, 2011 Share #4 Â Posted February 23, 2011 The old Sonnar? Quite a nice lens - similar to the Summarit 1.5, which I rather like. Just avoid busy backgrounds, as the bokeh can get quite wild at times. Link to post Share on other sites More sharing options...
Scola77 Posted February 23, 2011 Author Share #5 Â Posted February 23, 2011 Ok, just got this from Zeiss America: Â "The ZEISS C Sonnar 1.5/50 ZM is focus optimized at wide open aperture for use with film-based rangefinder cameras with the standard flange focal distance of 27.8mm. It is our experience that the sensor plane in digital rangefinder cameras can deviate from this standard, which can cause the focus shift to occur. Unfortunately, the sensor position can vary from camera to camera, so there is no way for us to guarantee the lens will be optimized for your specific camera. Â The Carl Zeiss service department in Germany can provide a slight adjustment to the focus optimization and in many cases this is sufficient. If you are interested in having this service performed on your lens, please send to our address below and include a completed service repair form (attached). Upon receipt, we will forward to Germany for repair. There is no cost for this service the the turn around time is approximately 4-5 weeks from receipt of the lens in Germany." Â Hell why not, I think I will try it... Link to post Share on other sites More sharing options...
bill Posted February 23, 2011 Share #6  Posted February 23, 2011 I cannot find a 50mm summilux anywhere, so I am "slumming it" with a zeiss sonnar.  *cough*...  Some of us chose to marry a brand new MP4 with a Sonnar last year in preference to a Summilux because they wanted a lens with character and a recognisable "fingerprint" rather than one that delivers sterile clinical precision  Regards,  Bill Link to post Share on other sites More sharing options...
Mike Shimwell Posted February 23, 2011 Share #7 Â Posted February 23, 2011 Advertisement (gone after registration) Ok, just got this from Zeiss America:Â "The ZEISS C Sonnar 1.5/50 ZM is focus optimized at wide open aperture for use with film-based rangefinder cameras with the standard flange focal distance of 27.8mm. It is our experience that the sensor plane in digital rangefinder cameras can deviate from this standard, which can cause the focus shift to occur. Unfortunately, the sensor position can vary from camera to camera, so there is no way for us to guarantee the lens will be optimized for your specific camera. Â The Carl Zeiss service department in Germany can provide a slight adjustment to the focus optimization and in many cases this is sufficient. If you are interested in having this service performed on your lens, please send to our address below and include a completed service repair form (attached). Upon receipt, we will forward to Germany for repair. There is no cost for this service the the turn around time is approximately 4-5 weeks from receipt of the lens in Germany." Â Hell why not, I think I will try it... Â There's a bit more to it than that (Zeiss in Oberkochen have advised elsewhere) that the C-Sonnar focus shifts (described as a feature of the sonnar design). C-Sonnars were focus calibrated for either f2.8 or f1.5 out of the factory. If calbrated for f2.8 then focus shift is experienced as progressive front focus at increasing apertures than 2.8 (i.e. 1.5 to 2.5). Similarly, if optimised for 1.5, then you experience back focus at smaller apertures, although the dof pretty well covers it by about 5.6 and for normal shooting distances (more than 6 feet say). The focus shift is the same on film or digital bodies, but digital is less 'forgiving'. You can learn to compensate by twidting the ring a bit or leaning back/forth as required. It's not a film cf digital feature really. Â Mine was optimsed by Zeiss in germany for 1.5 and is spot on at 1.5 on my M9 or my ZIs. At f2.8 I sometimes get the wrong (back) eye in focus and there isn't enough dof to cover the front. Effectively the depth of field runs from the focus distance back,but can be soft at the front of the range. Â It sounds like yours is optimised for f2.8 and you should decide whether you want to go to 1.5 before sending it in. Â It's a great lens and I am very happy with how it draws, in colour or black and white. Â Sorry for the long and rambling first post. Â Mike Link to post Share on other sites More sharing options...
hoppyman Posted February 23, 2011 Share #8 Â Posted February 23, 2011 That is a remarkable bit of double speak . In fact Zeiss in Germany describe this one as a 'classic reminescent of its predecessor from the 1930's and well suited to portraiture (which means softer and 'gentler') It certainly does have focus shift, exactly as would be expected from a faster spherical design. It may well be a pleasing lens, depending on personal preference but it is pretty silly for them to turn around the inherent better precision of the M8/9 focus into a disadvantage because it shows the limitations of their design more readily! Eunuchs boasting of their chastity. Â Â Â The nature of film means that it is not perfectly flat and has thickness for the focus plane to be positioned within/adjacent to. The M8/9 sensors effectively have zero depth in that regard and the sensors are adjusted as perfectly flat as possible. In that regrad they are less tolerant of lens design limitations (make them more apparent).You cannot remove the focus shift characteristic of any lens by adjusting it. You can only shift where the sharpest plane is positioned to give the best compromise at a particular foocus distance. Â Ok, just got this from Zeiss America:Â "The ZEISS C Sonnar 1.5/50 ZM is focus optimized at wide open aperture for use with film-based rangefinder cameras with the standard flange focal distance of 27.8mm. It is our experience that the sensor plane in digital rangefinder cameras can deviate from this standard, which can cause the focus shift to occur. Unfortunately, the sensor position can vary from camera to camera, so there is no way for us to guarantee the lens will be optimized for your specific camera. Â The Carl Zeiss service department in Germany can provide a slight adjustment to the focus optimization and in many cases this is sufficient. If you are interested in having this service performed on your lens, please send to our address below and include a completed service repair form (attached). Upon receipt, we will forward to Germany for repair. There is no cost for this service the the turn around time is approximately 4-5 weeks from receipt of the lens in Germany." Â Hell why not, I think I will try it... Link to post Share on other sites More sharing options...
nex100 Posted February 23, 2011 Share #9 Â Posted February 23, 2011 I recently got the Zeiss 50mm C Sonnar too. Mine is optimised at F2.8. For still life and architecture, I will need to focus slightly beyond the subject (approx. 1mm on the viewfinder) to get razor sharp pics. For portraits, I just focus normally and I get good results. Â Weird thing is that the focus shift does not seem to get in the way when shooting portraits. In fact I like the look of it at F1.5 (maybe it is because our faces are not really flat like inanimate objects). Â For landscape I shoot at F2.8 and I get corner to corner sharpness. Â I really like this lens and accept all of it faults and qualities. For its price it is hard to beat. I agree the learning curve is there but took me 3 days of practice on my own to overcome that. (Yes I am a slow learner). Link to post Share on other sites More sharing options...
jaapv Posted February 23, 2011 Share #10 Â Posted February 23, 2011 Ah! getting up to speed now. Not the "real" Sonnar aka Summarit, but the modern derivate! Link to post Share on other sites More sharing options...
ho_co Posted February 24, 2011 Share #11 Â Posted February 24, 2011 It's interesting that Zeiss is becoming so up-front about the focus shift of the C Sonnar 50. Â Hasn't the public awareness of focus shift with Leica lenses occurred pretty much since the introduction of the M8? Â It looks as if Zeiss were still in their coy stage in their response to the January 2007 LuLa review of the C Sonnar 50 (Zeiss M-Mount Lenses). Â Â "Ye shall know the truth, and the truth shall make you free." Link to post Share on other sites More sharing options...
charles-k Posted February 24, 2011 Share #12 Â Posted February 24, 2011 With shortage of Leica lenses, I opted for the ZM 50/1.5 Sonnar too. I have had 3 copies of the lens, and all were optimized for f/2.8. For me this was a problem, for portraits at f/1.5 making the most of the soft older style rendering. Focusing was hit and miss trying to capture the near eye/lashes. I sent the lenses back requesting for them to be optimized for f/1.5, but still came back the same. When the focus was nailed, the lens performed beautifully, but I was not willing to spend too much time. For mid distances and using f/2.8 and greater the lens is excellent. IMO, it is a shame to not be able to utilize the wide open aperture of this lens. So if you can ensure the lens is optimized for f/1.5, the lens should work brilliantly. Â Whereas the ZM 50/2 Plannar is sharp and very easy to focus on the M9. Excellent lens in every respect. I have still have the ZM 50/2 Plannar as a backup, to my 50 Lux Asph. Link to post Share on other sites More sharing options...
Mike Shimwell Posted February 24, 2011 Share #13  Posted February 24, 2011 With shortage of Leica lenses, I opted for the ZM 50/1.5 Sonnar too. I have had 3 copies of the lens, and all were optimized for f/2.8. For me this was a problem, for portraits at f/1.5 making the most of the soft older style rendering. Focusing was hit and miss trying to capture the near eye/lashes. I sent the lenses back requesting for them to be optimized for f/1.5, but still came back the same. When the focus was nailed, the lens performed beautifully, but I was not willing to spend too much time. For mid distances and using f/2.8 and greater the lens is excellent. IMO, it is a shame to not be able to utilize the wide open aperture of this lens. So if you can ensure the lens is optimized for f/1.5, the lens should work brilliantly. Whereas the ZM 50/2 Plannar is sharp and very easy to focus on the M9. Excellent lens in every respect. I have still have the ZM 50/2 Plannar as a backup, to my 50 Lux Asph.  That seems unfortunate. Mine was optimised at 1.5 by Zeiss in germany. Perhaps yours went to Cosina Voigtlander in japan - I have heard that they prefer not to optimise at 1.5 but will aim for a compromise setting. When corectly focused it is uite sharp even wide open in the centre field.  Mike Link to post Share on other sites More sharing options...
Viv Posted February 24, 2011 Share #14 Â Posted February 24, 2011 The only issue I have is when shooting wide open, there is a noticeable focus shift. Â THAT'S NOT AN ISSUE. IT'S A PROBLEM! Link to post Share on other sites More sharing options...
bill Posted February 24, 2011 Share #15 Â Posted February 24, 2011 Actually, it's a feature not a fault... Â Regards, Â Bill Link to post Share on other sites More sharing options...
tobey bilek Posted February 24, 2011 Share #16 Â Posted February 24, 2011 I remember Leica has a problem with original M digital. The film channel has debth and film uses it, therefore the RF is not calibrated to the pressure plate, but somewhere in the film track. Leica rep told me this 25 years ago when Leica had reps who knew you and were knowledgeable, not just salesmen. Â Along came digital, and the distance the RF had to be calibrated to was perfect and measurable. I do recall the original cameras went out calibrated to film standards as Leica did not even realize this. See what happens when you get all new people. Knowledge disappears. Â So now they have to set up RF differently for digital. Â For Zeiss to say tolerences are sloppy with regard to Leica digital register distance is plain absurd. That lens has focus shift and it needs to be calibrated to 1.5, not 2.8 like the original samples , otherwise why have a 1.5 lens. Now all the 5.6 shots are out of focus, but there is more tolerence there. 1.0 Noctilux is the same. 5.6 suffers, but you can bring it back in with an educated guess. Â What Zeiss needs to do is move the optical cell probably with shims. Digital or film m has nothing to do with the problem. All that was fixed years back. Link to post Share on other sites More sharing options...
UliWer Posted February 24, 2011 Share #17 Â Posted February 24, 2011 I think we are mixing up focus shift and miscalibration of rangefinder and lens focus. Â With any lens - be it Leica, Zeiss, CV or whatsoever - you can have the experience that the photo is out of focus, even if you are absolutely precise in focussing with the rangefinder. Reason for this can be a fault in the rangefinder or a fault in the lens. If only one lens shows this, it should be the lens. Zeiss should be able to calibrate the lens alone without looking at the camera so it focusses in exact alignment with the rangefinder. If it were true, that there are differences in the position of the sensor, they would be unable to do so, as they wouldn't know the exact position of the sensor without having the camera as well. To tell a customer: "The sensor is the problem, but send us the lens, so we take care of that" is nonsense. Â Focus shift is a completely different topic. Due to optical "errors" (which are based on physical laws) there will be a always a shift of focus if you change the aperture; how much it is, depends on the way those "errors" are corrected. This correction must be calculated in the optical design of a lens, you cannot correct the optical charactersitic of a given lens, which shows focus shift; if you would try to do so, the result could only be a new lens with new glasses. In some lenses the shift is obvious, in others you won't notice it. Leica made a new 35-Lux asph, to get rid of - most - of the focus shift characteristics it's precedessor showed; it's a new lens, not a "repaired" old one. So if somebody at Zeiss should tell a customer: "send us the lens, so we can correct its focus shift", he is either talking nonsense or he just uses "focus shift" for miscalibration. Â But in any case the focus can only shift, if you change the aperture. At a certain aperture the focus does not shift, but will be stable - either in or out of focus. So it does not make much sense to say: "My lens has a focus shift at f/1.5." You could only say: The lens is in (or out of focus) at f/1.5 and out of (or in) focus at another aperture. Link to post Share on other sites More sharing options...
Washington Posted February 25, 2011 Share #18  Posted February 25, 2011 Just as an aside I am still using the 50mm f1.5 Leitz Summarit which came new on my double stroke M-3. It exhibits many of the optical properties mentioned above minus the focus shift … and fine examples can be had for short money. I think Jappv mentioned he had one of these: what do you think of it Jappv? Link to post Share on other sites More sharing options...
jaapv Posted February 26, 2011 Share #19 Â Posted February 26, 2011 I think it is a great vintage lens, although the bokeh can be pretty wild at times - better to avoid busy backgrounds. And is the only lens I have that will transmit UV light... But is can be pretty hard to find an example where all lens elements are pristine. I have the impression some of the glass types used suffer from oxidation, making the lens rather contrastless. Link to post Share on other sites More sharing options...
thompsonkirk Posted February 26, 2011 Share #20 Â Posted February 26, 2011 I've tried a 1.5 Summarit only once, & thought it provided all the softness of a Sonnar or early Summilux with none of the 'glow.' It just looked dull to me. Â I've read that Sonnars were preferred by the 'classic' Leica photographers of the 50s for just this reason. Â Kirk Link to post Share on other sites More sharing options...
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