bpalme Posted February 5, 2011 Share #1 Posted February 5, 2011 Advertisement (gone after registration) So... from what I've been reading.. When you focus in the window(I have no RF experience) at say F1.4 then change to F 2 or whatever... the focus may be off. Can't you just refocus at that point and take care of the shift? I don't think I want to spend the bux for a ASPH II but I really want this focal length and speed. Should I really worry about this? I mean the version one ASPH still commands a high price so it can't be that bad can it? How many people here experience this as a problem? I read somewhere that it may be able to be adjusted at the factory if the send it in for service... but I can't find much on that. Link to post Share on other sites More sharing options...
Advertisement Posted February 5, 2011 Posted February 5, 2011 Hi bpalme, Take a look here Question about the Lux focus shift. I'm sure you'll find what you were looking for!
JWW Posted February 5, 2011 Share #2 Posted February 5, 2011 I'm assuming you are asking about the 35mm Summilux ASPH V1 focus shift. I had the ASPH I and to tell the truth, if it wasn't for all the posts regarding this I may never of noticed this but due to design constraints there is an inherent focus shift backwards as you stop down from f2 to around f5.6. This can be noticeable or not depending on the particular tolerances or focus setting on the lens. In my own experience it was not worth worrying about since any physical shift of holding the camera had a bigger effect than the focus shift on my lens example. It's easier to spot this on the digital M rather than the film M bodies. You can compensate for this by guessing but you can't use the rangefinder itself because the RF is set up totally independent from what the lens is seeing or experiencing. The optimum way to set up the lens is to set the lens up so at f1.4 the focus area is set up toward front focusing, then as the lens gets stopped down the focus can shift backwards but still stay pretty much within the DOF. The V2 corrects all this with the floating element and is my most used lens. Link to post Share on other sites More sharing options...
lars_bergquist Posted February 5, 2011 Share #3 Posted February 5, 2011 The focus shift is an optical act of life. In theory, all lenses do it, but very fast lenses do it in spades. Current Leica lenses as you know, lenses like the 1:0.95 Noctilux and the 50 and 35mm Summiilux ASPH, have in their design compensation factors that reduce the phenomenon to negligible proportions. You can have an expert move the focus of, say a 1:1 Noctilux so that the shift is less noticeable at mid-apertures. But this is done at the price of slightly de-focusing the lens at 1:1, which makes is pretty useless at that aperture because of the extremely shallow depth of field – off focus will be totally off focus. Remains two options. Either you learn to compensate the shift by the exact movement of the focus ring that does the trick at each aperture and subject distance – a trick I would not trust myself to perform – or just bite the bullet and never stop the lens down. After all, it is f:1 that you buy the lens for. But the magic is in the picture, not in the numbers. I have seen too many totally uninteresting pictures taken through a Noctilux or a 21 or 24mm Summilux, and accompanied by a breathless caption: "Wow, this picture was taken with a ( .... ), wow, isn't it wonderful!" where in many cases it was impossible to tell the difference between that and a picture taken with a more prosaic lens. You can play many tricks of "differential focus" with a 50mm Summilux. What makes us special is not what we own but what we do, not our tools but how we use them. The old man from th Age of the 5cm Xenon Link to post Share on other sites More sharing options...
marknorton Posted February 5, 2011 Share #4 Posted February 5, 2011 Important to remember that the camera has no knowledge of the working aperture and the focussing aid - the rangefinder - will not present you with any kind of focussing error as you stop down. Second, the focus shift is most noticeable at close focussing distances because the lens is not computed to work optimally at these distances and spherical aberrations increase towards close focus. The more modern lenses have close focus correction (itself a source of additional complexity and potential trouble) to reduce the spherical aberration at close focus and consequently the focus shift when you stop down. Key to understand though is that the lens doesn't have any kind of compensation as it is stopped down. The original Summilux ASPH is, in my experience, most problematic at distances of less than 5m and f2.8 to f4. Outside that range, it's fine. The lens is, by modern standards, a flawed design but it's the best they could do at the time. Link to post Share on other sites More sharing options...
Lord Fluff Posted February 5, 2011 Share #5 Posted February 5, 2011 ... (I have no RF experience) I don't think I want to spend the bux for a ASPH II but I really want this focal length and speed. I think the other posters may have missed the bigger question.... Do you know you want a rangefinder? And if so, why? Unless you are committed to burning money perhaps you should try some of the more affordable end of the market (say a Voigtlander 35/1.4 or similar) and see if RFs suit you - they don't work for everyone, and even for those that like them, they don't work at all for certain sorts of photography. Perhaps you're enjoying reading up on the subject generally, in which case, enjoy, but you're way early in your RF 'career' to be worrying about focus shift on highly expensive (and hard to find) Leica glass. Link to post Share on other sites More sharing options...
Jager Posted February 5, 2011 Share #6 Posted February 5, 2011 Some have experienced the problem. Some not. Which is not to say that focus shift does not exist - as Lars points out, it is an optical fact of life in all lenses, most particularly in fast ones. But most photographers are not even aware of the phenomenom, which suggests it remains a theoretical issue for most. My copy of the 35 Lux ASPH v1 was (is) not a problem on film. And it's not a problem on digital. When I evaluated all my lenses with a carefully calibrated test rig a year ago my 35 turned out to have a tiny amount of front focus at f1.4, which then drifts back to a tiny amount of back focus at f2.8. The amount, in both cases, is less than the shot-to-shot variation I get when refocusing via the rangefinder patch. Which is to say I don't notice focus shift at all in actual practice. I use all f-stops, with a clear bias towards wide open or near-wide open apertures. Like having a lovely, warm-hearted girlfriend who you then read is supposed to have PMS, I never knew I had a problem with my 35 until I read I was supposed to. I certainly wouldn't dismiss a v1 Lux out of hand, if you come across a good sample. Link to post Share on other sites More sharing options...
Xmas Posted February 5, 2011 Share #7 Posted February 5, 2011 Advertisement (gone after registration) So... from what I've been reading.. When you focus in the window(I have no RF experience) at say F1.4 then change to F 2 or whatever... the focus may be off. Can't you just refocus at that point and take care of the shift?I don't think I want to spend the bux for a ASPH II but I really want this focal length and speed. Should I really worry about this? I mean the version one ASPH still commands a high price so it can't be that bad can it? How many people here experience this as a problem? I read somewhere that it may be able to be adjusted at the factory if the send it in for service... but I can't find much on that. Hi You could re-focus at f/2 (stopped down) on a SLR but not on a rfdr. If you are using a M8 or M9 you probably need to wait for the type II, a type I may annoy, you can try them in a shop, with a ruler or news paper if you can visit Leica shops, select one that is ok, but you may need to try an number of examples. But the lens may then only be ok on the M body you tried it on. The type I were designed for film cameras, and most will be ok on most film cameras. Think Solms charge about 250 GBP to adjust a type I to M body, and they may need the body to adjust its registration and rfdr to be exact. Same for a Noct, they have been saying this from '79. Noel Link to post Share on other sites More sharing options...
bpalme Posted February 5, 2011 Author Share #8 Posted February 5, 2011 Thanks for all the feedback.. I think I'm just going to go ahead and get a Version I ASPH. Maybe get on the list for a Version II if i find any issues that bug me. Link to post Share on other sites More sharing options...
bpalme Posted February 5, 2011 Author Share #9 Posted February 5, 2011 I think the other posters may have missed the bigger question.... Do you know you want a rangefinder? And if so, why? Unless you are committed to burning money perhaps you should try some of the more affordable end of the market (say a Voigtlander 35/1.4 or similar) and see if RFs suit you - they don't work for everyone, and even for those that like them, they don't work at all for certain sorts of photography. Perhaps you're enjoying reading up on the subject generally, in which case, enjoy, but you're way early in your RF 'career' to be worrying about focus shift on highly expensive (and hard to find) Leica glass. I'll be buying used so if it doesn't work out I'll just sell things. Thanks for the suggestion but I don't want to buy lower end stuff then have to turn around and sell that to upgrade. Is it just me or does the quick reply not work for others? Link to post Share on other sites More sharing options...
AGeoJO Posted February 5, 2011 Share #10 Posted February 5, 2011 I wouldn't consider Leica lenses as investment but if you buy used ones at a fairly good price, especially from direct users, a year or two down the road you may be able to sell those lenses at a higher price, at least, you wouldn't loose money. But you have to stick to selected lenses that are in demand and the 35mm Summilux is in that category. I had that lens and didn't notice any focus shift from normal usage. If I stopped down, I did so to about f/4.0 max. I used this lens more so on my M8 but less so using my M9. I sold that lens in anticipation of getting the version II but decided not to go for it and I ordered a Nocti instead. It is a long story but I ended buying another one for a little more money and without the 6-bit code, too . Silly me. I haven't noticed any ugly focus shift on the second one either. If you encounter this issue and it is more than to you liking, just make a conscious effort of turning the focusing ring towards front focus a tiny bit if you stop down the lens to f/4.0. It is a wide angle lens and the depth-of-field should take care of it. Good luck, you will enjoy the lens! Link to post Share on other sites More sharing options...
Lord Fluff Posted February 8, 2011 Share #11 Posted February 8, 2011 I'll be buying used so if it doesn't work out I'll just sell things. Thanks for the suggestion but I don't want to buy lower end stuff then have to turn around and sell that to upgrade. Ok, good luck in that case. I'll confess I do still find your whole line of enquiry a little odd - a bit like posting on a car forum as to whether buying a 2WD or 4WD Porsche 911 is better, without having yet passed your driving test. My guess will be that at least for quite some time getting your shots in focus will be a challenge (still is for some of us, depending on how you shoot), and a lens with known focus shift will add to that somewhat. I guess though that your heart is set on owning a Leica and a Lux, so perhaps ownership is the priority for you, rather than usability. It's worth noting that a used Summicron is a stunning performer, without the big ticket price. You'll find you need to hit 'Post Reply' or 'Quote' to be able to type in the 'Quick Reply' box. Link to post Share on other sites More sharing options...
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