Applecake Posted January 31, 2018 Share #1 Posted January 31, 2018 Advertisement (gone after registration) Hi y'all - long time lurker and first time poster here. Just had a quick question for you guys about Leica lenses. I recently upgraded from the Q to the M10 w/ 35mm 'cron - loving it so far! One thing I noticed is that when the lens is focused to infinity, I sort of have to dial the focus ring back slightly to achieve true RF alignment of an object a few miles away. I was under the impression that at infinity, everything at infinity (miles away) should be perfectly aligned in the rangefinder patch. Brought this up with the reps at the Leica store and was advised that this is totally normal and that Leica lenses are built with tolerance for weather (thermal expansion I'm guessing he was referring to) so you always kind of have to dial focus back slightly when focusing to infinity. Is this a real thing? Seen many threads around here saying something different. Any insight from y'all veterans would be fantastic, thanks! 1 Quote Link to post Share on other sites More sharing options...
Advertisement Posted January 31, 2018 Posted January 31, 2018 Hi Applecake, Take a look here Leica lens "thermal expansion". I'm sure you'll find what you were looking for!
jaapv Posted January 31, 2018 Share #2 Posted January 31, 2018 Well, that is not quite true. Normally M lenses will reach infinity at the hard stop. If yours doesn't it may be that the roller on the arm that transfers the focus to the camera needs a minuscule adjustment. First check whether the lens is 100% sharp at infinity when turned against the stop. If so, use a 2 mm Allen Key to give a small twist to the roller. Check again for coincidence. Readjust if needed. When you have coincidence you will find focusing improved across the range. You will find the roller at the top of the camera mouth. Should you be unwilling to do this adjustment yourself, any decent Leica repair facility (or even some expert shops) should be able to do it for you whilst you wait. This is meant to be a user adjustment and will not invalidate your warranty. The thermal expansion argument is valid for long lenses and adapters, not for shorter ones.. 5 Quote Link to post Share on other sites More sharing options...
Applecake Posted January 31, 2018 Author Share #3 Posted January 31, 2018 @jaapv thanks for the response! wouldn't adjusting the roller arm adjust focus across the entire range? It doesn't look like I have backfocus issues at close or mid range. I wouldn't want to throw focus off at other distances... Quote Link to post Share on other sites More sharing options...
jaapv Posted February 1, 2018 Share #4 Posted February 1, 2018 Not really, a minor change, yes. However, the Allen screw on the roller arm is meant for infinity adjustment, the inner hard-to-reach one is for close up. In practice there usually is a minor improvement throughout the range. Even if it would work adversely it is simple to reverse the adjustment, though. There is also a bending adjustment, that should never be attempted. Quote Link to post Share on other sites More sharing options...
pico Posted February 1, 2018 Share #5 Posted February 1, 2018 (edited) Ah, the modern difficulty of infinity. We much reach back to the German philosopher Hegel, The Incomprehensible. He inserted a meme into German minds that "Infinity cannot be measured" or something like that which in modern optics translates as close enough. especially for popular commercial work. Make two pictures at a really far away object. What is far away? What ever you consider infinity. In my case it is a radio tower about three miles away. One photo focused in the rangefinder, adjusting as necessary to align and another with the lens marking at infinity. Are the differences significant? If you cannot really tell, then all is close enough. Edited February 1, 2018 by jaapv 2 Quote Link to post Share on other sites More sharing options...
xiaubauu2009 Posted February 1, 2018 Share #6 Posted February 1, 2018 (edited) Leica M is a precision instrument that is operated with 2 major mechanical component, the lens focus mechanism that is linked to the RF arm through direct physical contact. Either one of this instrument is off, you will get inaccurate focusing. This is both the appeal and downside of this system.... (leaning more to appeal) Interesting note, which I don't know if it's true or not... I am based in Shanghai, China. I went to the shop where I normally buy my Leica gear and they are one of the biggest grey market Leica provider in Shanghai (don't ask me why I get grey market, cause the normal retail here in China is about 40~50% more expensive than grey, so the choice is easy). Anyway, the story is that I was getting a Summicron 35mm ASPH, the latest version, can't remember which. And I was testing one before buying brand new. Upon testing, I found the lens to be back focusing quite heavily.... I thought it was my RF that has problem, swap to a second hand 50 noctilux 0.95 and it's focus pitch perfect! Then I know it's the lens, so I requested a second one to be tested... lord behold, it back focus again.... the seller become concern, took out all his new 35mm Cron of the same batch (he got in about 6 of them) and tested each of it... and it all display back focus.... so, we just sat there in awe with Leica's QC... 1 and a half year later... which was last month... I borrow my friend's Lux 21mm to see whether I like the focal length and the f1.4 effect... I discovered my M246 has RF misalignment, so I brought it in to Leica Service center in Shanghai (hooray for this as they finally opened one in China since it's now one of their biggest customers in the world), they fix the problem for free since the m246 is still in warranty. But upon fixing, they discover that the Lux 21 is complement out of focus as it is now front focusing quite heavily.... which they claim is very odd as the lens has not received any knock and drop. But since it's my friend's Lux and Shanghai doesn't have the instrument to adjust lens, i let him to sort out the problem himself, which he did by sending it to HK capable Panda Camera for repair. Upon receiving the lens, Panda Camera said they can't fix the lens as modern Leica M lens need specialized instrument and jig to adjust. However, he said that Leica Wetzlar own factory instrument, particularly the jig is known to, in few rare cases, to go out of alignment without them knowing, and hence, this will influence the entire batch of leica M lens setup, and hence explain why the whole batch of Cron 35mm were off.... Anyway, just a story to consider when you think that M should focus perfect all the time.... when it didn't, you need them adjusted... that's all... Edited February 1, 2018 by xiaubauu2009 3 Quote Link to post Share on other sites More sharing options...
250swb Posted February 1, 2018 Share #7 Posted February 1, 2018 Advertisement (gone after registration) Is the lens brand new? If not it may be an older 35mm Summicron that has had an aftermarket coded mount fitted, some are more accurate than others, although I suspect they all come from the same factory. Quote Link to post Share on other sites More sharing options...
albertknappmd Posted February 7, 2018 Share #8 Posted February 7, 2018 I usually have my dealer, David Farkas, check for back focusing when I purchase lens. Have never seen it in over 20 years... Albert Quote Link to post Share on other sites More sharing options...
abphotog Posted February 25, 2018 Share #9 Posted February 25, 2018 Hey, I live in Montreal and hop between indoors and outdoors all the time and am wondering the same thing, I’m praying that it is thermal expansion as both lenses I use on my m10 focus beyond infinity. I’ve only noticed my camera focusing (both patch and lens) beyond infinity since sending it out to get a shutter replacement. Is it from the repair, or just cold weather? I’m itching to find out! And no, it’s not my patch being out of calibration as the lens and rangefinder both go beyond infinity. Any help would be appreciated! Quote Link to post Share on other sites More sharing options...
pico Posted February 25, 2018 Share #10 Posted February 25, 2018 Hey, I live in Montreal and hop between indoors and outdoors all the time and am wondering the same thing, I’m praying that it is thermal expansion as both lenses I use on my m10 focus beyond infinity. Funny how nobody considers how our eyes behave in sub-zero weather. Blame the camera? Quote Link to post Share on other sites More sharing options...
abphotog Posted February 25, 2018 Share #11 Posted February 25, 2018 That’s not really a helpful reply and a rude assumption. I assume anyone who purchases an m10 and then comments about something that bothers them, has tested the problem thoroughly...at least I have. I even got my girlfriend to try a we both concluded that the camera does focus beyond infinity. I’m awaiting a response from Leica in the meantime, but can anyone else shed some light on this? I really enjoy a hard stop infinity, and I’m a little bugged that it’s not happening right now. Quote Link to post Share on other sites More sharing options...
pico Posted February 25, 2018 Share #12 Posted February 25, 2018 (edited) That’s not really a helpful reply and a rude assumption. Unless, of course, if it true. Also consider user-error or user expectation which is not uncommon. How do you verify that the system focuses beyond infinity, please? And include aperture and shutter speed, and what you believe infinity to be - it is really far away. Then there are normal atmospheric influences, humidity and haze. Edited February 25, 2018 by pico 1 Quote Link to post Share on other sites More sharing options...
abphotog Posted February 25, 2018 Share #13 Posted February 25, 2018 I’ve done the moon, stars, I’ve done landscapes that vary from 500m to over a km, in -10c to +6c, in day and night using various apertures on my 50 Cron v5 and my 35 Distagon zm. I just tested it at various distances over a frozen river, trees, sailboat masts, and airplanes...all of which are just slightly out of focus on the patch, and out of focus in the images at infinity, I have to backfocus to align them. So I’ve lost the hard stop. The only conclusion I’ve come to is that the distance from the sensor to the lens might have changed when Leica changed the shutter, OR thermal expansion/cold weather is changing the way the lenses function in the cold. The patch is appears to be aligned on anything closer, and this behavior occurs in live view as well. Anyone else here care to share thoughts? 1 Quote Link to post Share on other sites More sharing options...
tobey bilek Posted February 26, 2018 Share #14 Posted February 26, 2018 A "friend" always had a mismatch between optical visoflex and sensor. While in for service, that was repaired and not the two match perfectly. The very best thing on mirrorless SLR is these things match up all the time. Quote Link to post Share on other sites More sharing options...
pico Posted February 26, 2018 Share #15 Posted February 26, 2018 (edited) A "friend" always had a mismatch between optical visoflex and sensor. While in for service, that was repaired and not the two match perfectly. The very best thing on mirrorless SLR is these things match up all the time. Oh, Tobey. I take that as discouraging. Reality bites! Thank you, nonetheless. Edited February 26, 2018 by pico Quote Link to post Share on other sites More sharing options...
abphotog Posted February 26, 2018 Share #16 Posted February 26, 2018 Got confirmation from both camtec and Leica, some m10s leave Germany calibrated to a hard stop, whereas last 3 years, leica has started to push focusing beyond infinity, so that we can achieve critical infinity on older lenses. Neat! So Leica nj said they calibrated my m10 to go beyond infinity for that very reason. It’s only a hair off, but it’s noticeably out of focus at 200% on anything below ~f5.6 1 Quote Link to post Share on other sites More sharing options...
Jared Posted February 28, 2018 Share #17 Posted February 28, 2018 That response from Campeche and Leica doesn’t make sense to me. 1) The distance between the flange and sensor/film plane has never changed for as long as Leica has been making M. Ointment cameras. How could it? Just doesn’t make sense. 2) Presumably, a lens can be made such that the lens can be focused slightly past infinity to account for very cold weather conditions. You do, in fact, see this on some Nikon and Canon telephoto lenses in particular. But the infinity mark on the lens always matches the actual infinity location at standard temperature (around 25C). I have yet to see a Leica lens that can turn past the infinity mark on the lens. Of course, there are no M lenses beyond 135mm so that’s not surprising. The larger the magnification, the more you have to account for differences in CTE between the optical tube and the glass elements. Generally not an issue at moderate focal lengths where the shift is small and the depth of field is large. 3) Even if some Leica lenses do focus past infinity (as indicated on the lens barrel, not in the viewfinder), I wouldn’t expect Leica to have to make a change to the camera calibration procedure. That would be a property of the lens, not a property of the camera, so Leica would still calibrate at 2m the same way they always have. I think someone is not being straight with you. Put a ruler about 2m from your camera oriented so it’s at 45 degrees to the optical axis. Focus somewhere near the middle of the Frame and take a picture. I suspect you will find the focus point you chose is not the actual point of best focus in your image. That means the rangefinder is slightly off. By far the simplest explanation. If that’s the case, follow Jaap’s advice. Quote Link to post Share on other sites More sharing options...
jaapv Posted February 28, 2018 Share #18 Posted February 28, 2018 Got confirmation from both camtec and Leica, some m10s leave Germany calibrated to a hard stop, whereas last 3 years, leica has started to push focusing beyond infinity, so that we can achieve critical infinity on older lenses. Neat! So Leica nj said they calibrated my m10 to go beyond infinity for that very reason. It’s only a hair off, but it’s noticeably out of focus at 200% on anything below ~f5.6 It sounds to me like somebody is trying to talk his way out of having to do something. As he claims that Leica is deliberately miscalibrating "some M10 cameras" I would take this up with Leica Germany. 1 Quote Link to post Share on other sites More sharing options...
jmahto Posted March 2, 2018 Share #19 Posted March 2, 2018 Ah, the modern difficulty of infinity. We much reach back to the German philosopher Hegel, The Incomprehensible. He inserted a meme into German minds that "Infinity cannot be measured" or something like that which in modern optics translates as close enough. especially for popular commercial work. Make two pictures at a really far away object. What is far away? What ever you consider infinity. In my case it is a radio tower about three miles away. One photo focused in the rangefinder, adjusting as necessary to align and another with the lens marking at infinity. Are the differences significant? If you cannot really tell, then all is close enough. I routinely travel beyond infinity for my daily commute to work. Quote Link to post Share on other sites More sharing options...
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