tashley Posted February 22, 2007 Share #1 Posted February 22, 2007 Advertisement (gone after registration) OK I really am starting to pull my hair out, foam at the mouth and doubt my fundamental understanding of optics. Regular readers might recall last week I posted that having received my 30% discount lens, a 35mm 1.4, I headed happily off to Venice to take some snaps of the Carnival. Day 1 saw a growing realization that focus on the new lens was off and on my return home, after much testing and thinking, I realised that it was backfocusing increasingly as it stopped down Kudos to Solms, after some spitting my new lens arrived today (and guess what, I'm leaving in an hour to go to Viareggio to shoot the carnival there) and of course I ran the same test. It's a ruler test. Camera 160 ISO, on very solid tripod, film plane one metre from the central mark on a long ruler running away from me with an exactly parallel large logo'd box to aid focus and a 1.25 magnifier. Shots at every aperture from 1.4 thru 16. Guess what? You got it! The lens has perfect focus on my plane of focus at 1.4, then through 2, 2.8, 4 and 5.6 the plane of focus gradually slips backwards to around 7cm behind where I have actually focussed. At f8 there's enough DOF for the original point of focus to come back to the same level of sharpness as at 1.4. Now this is EXACTLY the same pattern as the one I returned. Silly me, didn't check the serial number of that one so maybe it just round-tripped rather than got replaced (they wouldn't do that would they?) or maybe there's a dud batch and QC is stressed at the moment. OR possibly they all do this, it's a feature of the optic, and I should just shut up and adjust my focus methods. Please someone, help me retain my sanity. I have a flight to catch! Tim Link to post Share on other sites More sharing options...
Advertisement Posted February 22, 2007 Posted February 22, 2007 Hi tashley, Take a look here Hair coming out in chunks - new 35mm 1.4 backfocus. I'm sure you'll find what you were looking for!
wattsy Posted February 22, 2007 Share #2 Posted February 22, 2007 My 35/1.4 ASPH behaves in exactly the same way. I took it to Milton Keynes last week and they agreed that there is something out of whack about the lens (they used their normal analogue testing equipment). It's now in Solms. Link to post Share on other sites More sharing options...
tashley Posted February 22, 2007 Author Share #3 Posted February 22, 2007 My 35/1.4 ASPH behaves in exactly the same way. I took it to Milton Keynes last week and they agreed that there is something out of whack about the lens (they used their normal analogue testing equipment). It's now in Solms. I'd love to read a review of the lens somewhere and see if they found the same thing - it's a pity that Irwin Putt's site is harder to navigate than Bombay in rush hour... I'm sure there's something on there! Tim Link to post Share on other sites More sharing options...
jaapv Posted February 22, 2007 Share #4 Posted February 22, 2007 Ah -ye olde focus shift. The Noctilux is a well-known offender in this respect, but I was not aware the Summilux 35asph did this, nor to this extent. It may well be one needs to compensate for this in use. The M8 enables us to see this, but is was not as noticable on film. Link to post Share on other sites More sharing options...
tashley Posted February 22, 2007 Author Share #5 Posted February 22, 2007 Thanks Jaap - would you say it is characteristic of all samples of the lens are just some? In other words, is it a built in side effect of the optical design or if I keep trying will I get one that doesn't do it? Best Tim Link to post Share on other sites More sharing options...
hankg Posted February 22, 2007 Share #6 Posted February 22, 2007 I was speaking to a retailer yesterday (I'm returning a 90/4 MACRO that backfocused wide open) and he's pulling his hair out. He's got 5 Nocts that he can't get to focus properly on M8's. He was wondering if there is something wrong with the M8. The 'problem' is that in the good old days, film buyers depending on how often and at what size they made prints might never realize (or only after seing a pattern over a long time) that their lens wasn't focusing at the point of focus. With digital 5 minutes after the lens comes out of the box your examining the result at 5,000% on the screen. This is not exclusive to Leica, DSLR owners (if their paying attention) have the same problems. I just got an M8. I purchased a used 50/1.4 preASPH, a used 21/2.8 preASPH and the new 90/4. All of them backfocused. The 90 had the least error, the 50 was wildly out. I am happy to report that the M8 RF was dead on. I had Don at DAG get everything spot on wide open. Focus shift with aperture change is common to a lot of lens (maybe it happens to some degree with all lens designs need an engineer to answer that). The faster the lens the more likely it will be noticable. I don't know what 'normal' shift is for the 35/1.4 but you might want to find out. Link to post Share on other sites More sharing options...
jaapv Posted February 22, 2007 Share #7 Posted February 22, 2007 Advertisement (gone after registration) I do not know for this lens particularly, it may be that yours is out of tolerance. It seems that this problem is unavoidable with high-speed asymmetrical lens designs. A rough idea is that the place the aperture is in, when asymmetrical in respect to the path of the light, will produce different "bending"of the lightrays at different f-stops. On film one does not notice it as much, as one does not usually enlarge to the size of 100% crop within seconds of taking the photograph, plus the transition between sharp and oof is more clearly defined on sensors than on film, giving rise to photographers noticing the phenomen these days. On a SLR one can avoid it by focussing at aperture, but that will, of course, diminish accuracy. Edit: Hank is right, it may well be that the average M8 owner is even more sensitive to such things than the average DSLR owner. After all, we are paying the price for "the best" and that may make us look even closer. Link to post Share on other sites More sharing options...
drjon Posted February 22, 2007 Share #8 Posted February 22, 2007 I have expereienced similar focusing issues with my M8 and the 35mm asph 1.4; it has been back to Solms where they said it was basically OK but made some minor adjustments. There was definitely some improvement after this - probably imagined on my part. I have several other M lenses and they seem fine but all with some out-of-focus issues sometimes. My conclusion is similar to others: focusing a rangefinder (especailly if you are not 18 years old or thereabouts) can be an issue; scrutinising images at 100% is defintely an issue; we tend to use our M lenses at wide apertures which accentuates any mis-focusing; the level of detail available from the M8 is relatively high. My prints which are rarely wall size are excellent and very sharp from the M8 - even before the 35mm was 'fixed'. I only really notice the issue with this lens when focsuing close up at wide aperture - a sure sign of user error being the likely culprit. I can live with it. And I can't live without my M8. Link to post Share on other sites More sharing options...
d_brown Posted February 22, 2007 Share #9 Posted February 22, 2007 Hello, Tim! Sorry to hear about your frustration with the 35mm LUX. I have THREE new 35s and am having problems with ALL of them! My first 35 Asph backfocused so bad it was unusable. Imagine receiving your new M8, mounting the 35mm Lux and taking some fuzzy test snaps. I was thinking "what the hell did I just buy?" Later I mounted my Tri-Elmar and suddenly the camera was *much* better, but still not sharp as it should be. I noticed that many shots were backfocused. I mounted more lenses and all were backfocused. The wide angles looked better because of increased DOF, but still not good. I mounted an old 1960s 90mm Cron and the problem was apparent--the camera's rangefinder definitely caused backfocus. I adjusted the rangefinder so my old lenses from the 1960s focused correctly. Focusing on an antenna on a water tower 1/2 mile away showed that the lenses were at their infinity stop when the rangefinder images exactly coincided. Now all my lenses focused correctly except the 35mm Lux! The M8 evidently wasn't fully checked before it was shipped. I received a second M8 and this time the rangefiner was adjusted correctly at the factory. All lenses focus correctly except the 35mm Lux. So I bought a 35mm Cron. Guess what? It backfocuses almost as badly as the Lux. I need a good 35 as I'm doing a long-term project at an indoor farmer's market and the Tr-Elmar just isn't quite fast enough at f4. So I bought another 35mm Lux. Guess what? It backfocuses the same as the first one! I called NJ and they say my camera needs to be adjusted. Just send it with the lens and they will look at it. Well, they already have my first M8 and first 35mm Lux and don't seem in any hurry to fix them. Germany finally confirmed receipt of the camera but won't acknowledge having the 35mm Lux. If I send them another, I'll be back to using the 1DsII (which probably wouldn't be a bad idea). We'll see how they do with the first one--if I ever get it back. So ONE LAST TRY! I have a 35mm ZEISS Biogon arriving today. I'll let you know. Again, sorry for your trouble, Tim and all. Hope you soon have better luck than I am right now. Dale Link to post Share on other sites More sharing options...
jaapv Posted February 22, 2007 Share #10 Posted February 22, 2007 I am happy to report tha my 35 summicron asph focusses spot on on both my bodies. Link to post Share on other sites More sharing options...
ChrisC Posted February 22, 2007 Share #11 Posted February 22, 2007 Tim - I completely understand your exasperation and hope your lens problem is resolved soon. Perhaps because with cameras and camera manufacturers, I am completely agnostic; I detect an undercurrent of Leica belief in this thread that disturbs me. Leica lenses are horribly expensive, we are constantly reminded of their fabulous quality, that they are the reason for choosing 'M' photography. The extra fast lenses are often heralded as the flagship lenses of the system. Are contributors seriously suggesting, if these lenses have aperture dependant shifting focus, that we customers accept it as a working inconvenience? If so, how does one achieve a tenet of M photography; the meticulously placed point of focus? A lens whose focus is erratic, is of no use to me regardless of it's cost. ...................Chris Link to post Share on other sites More sharing options...
jaapv Posted February 22, 2007 Share #12 Posted February 22, 2007 Chris, the problem is not restricted to Leica lenses. All asymmetrical high-speed lenses of any make exhibit this effect to a greater or lesser degree.. Link to post Share on other sites More sharing options...
hankg Posted February 22, 2007 Share #13 Posted February 22, 2007 You can ask the same question on a Canon pro forum and get similar experiences with back-focusing with lenses on digital bodies. If the lens is new, Leica service should be able to adjust it in a reasonable time frame. It doesn't sound like Leica service are performing as well as they should. I imagine they have lots on their plate now with the M8. If not covered by warranty I prefer independent service outfits that have built stellar service reputations in the Leica community. You know who is working on your lens and that they have extensive experience. Actually I think I would rather pay for the service if its just a focus adjustment then put up with the aggravation and frustration. It sounds like this problem has caused Tim not only aggravation but a lot of money. It would probably be a lot cheaper to have a reliable 3rd party look at the lens. A focus adjustment is not to costly and if it can't be adjusted you will know you have a defective product. Link to post Share on other sites More sharing options...
Jamie Roberts Posted February 22, 2007 Share #14 Posted February 22, 2007 Ooog...this sounds strange. Shouldn't be that far off IMO. My 35 1.4 focuses just fine throughout the aperture range, but I had to adjust the distance arm to get me on the money wide open (all my lenses). Didn't have to send the camera back though. But if the short focus adjustment is off, you need Leica service to adjust that. I have a chrome version of the lux ASPH; don't know if that could possibly make a difference (it *is* heavier ). Link to post Share on other sites More sharing options...
glenerrolrd Posted February 22, 2007 Share #15 Posted February 22, 2007 Did I misunderstand something. I thought all the backfocus threads suggested the small adjustment to the focus cam with the 2mm wrench..but this affected close focus as well as infinity? What did I miss? Link to post Share on other sites More sharing options...
Shootist Posted February 22, 2007 Share #16 Posted February 22, 2007 Did I misunderstand something. I thought all the backfocus threads suggested the small adjustment to the focus cam with the 2mm wrench..but this affected close focus as well as infinity? What did I miss? The wheel adjustment with the 2 mm allen wrench is for infinity but will also affect the close focusing to some degree. IMHO neither of these adjustments should be made by the end user. But some on this forum have adjusted the wheel with no ill effect. Link to post Share on other sites More sharing options...
jaapv Posted February 22, 2007 Share #17 Posted February 22, 2007 The wheel adjustment with the 2 mm allen wrench is for infinity but will also affect the close focusing to some degree. IMHO neither of these adjustments should be made by the end user. But some on this forum have adjusted the wheel with no ill effect. There is nothing wrong with adjusting infinity focus. Leica M users have been doing that for over fifty years and I am sure Solms regards that as "owner maintenance". If anything, the replacement of the slotted screw by a Allen wrench has made it even (a lot!) easier. Link to post Share on other sites More sharing options...
wilfredo Posted February 22, 2007 Share #18 Posted February 22, 2007 I'm wondering if pictures could be posted so we can have a visual of the problem? Wilfredo+ Link to post Share on other sites More sharing options...
Guest leicawanabe Posted February 22, 2007 Share #19 Posted February 22, 2007 more here: M8 Back Focus Test - a photoset on Flickr Link to post Share on other sites More sharing options...
sparkie Posted February 22, 2007 Share #20 Posted February 22, 2007 looks like slight 'Front' focus in those posted pics Link to post Share on other sites More sharing options...
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