LotharZhou Posted June 14, 2011 Share #1 Posted June 14, 2011 Advertisement (gone after registration) Hi, I have recently bought a brand new chrome 2/35mm asph in London 2 months ago, with 6 bit coding. However after a few hundreds shots I found at infinity the lens does not render image as sharp as the edge and corners. In the center of the photo, it's slightly blured and creamy. I sent the lens to Solmser and they sent it back without fixing it, then I took the lens and my M8 personaly went to Solmser, they tweaked the lens and it's slightly better but still no way near the expectation from a normal 2/35mm asph. Recently I sent the lens again to Leica, their quality control department replied it might be a bug whcih they yet to announce, it seems very very odd and strange to me, Leica said the lens was made for analog camera only and resitricted on digital Ms. Do any of you have an idea what is going on with this? The lens is perfectly sharp at close range, not at infinity, at least in the center part of the photos. Any ideas and replies are appreciated! Zhou Link to post Share on other sites More sharing options...
Advertisement Posted June 14, 2011 Posted June 14, 2011 Hi LotharZhou, Take a look here New 2/35mm asph center sharpness issue at infinity?. I'm sure you'll find what you were looking for!
LotharZhou Posted June 14, 2011 Author Share #2 Posted June 14, 2011 This is 100% crop from the center Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/154258-new-235mm-asph-center-sharpness-issue-at-infinity/?do=findComment&comment=1701840'>More sharing options...
LotharZhou Posted June 14, 2011 Author Share #3 Posted June 14, 2011 this is the same photo but 100% crop from corners Welcome, dear visitor! As registered member you'd see an image here… Simply register for free here – We are always happy to welcome new members! Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! ' data-webShareUrl='https://www.l-camera-forum.com/topic/154258-new-235mm-asph-center-sharpness-issue-at-infinity/?do=findComment&comment=1701841'>More sharing options...
LotharZhou Posted June 14, 2011 Author Share #4 Posted June 14, 2011 This is their reply regarding this issue, hard to believe though. Dear Mr. Zhou, Thank you for your mail. We forwarded your lens to our quality control department. They just told us that there is no fault with the lens. It was constructed for analog cameras and is for use with digital cameras restricted only. When do you leave Germany? Kind regards Customer Service Link to post Share on other sites More sharing options...
ho_co Posted June 14, 2011 Share #5 Posted June 14, 2011 Lothar--I like the "When do you leave?" line! The 35 Summicron is one of the older lenses in Leica's stable at the moment, so it's reasonable for Leica to make that argument. Remember that with the 35/1.4 they commented in LFI that "if we'd been designing it today [for the digital cameras], we'd have given it a floating element." They published that a year or so before introducing the new version of the lens with floating element. IOW, "pre-digital design" is a valid argument. My suggestion would be to focus a little nearer than infinity if you want the center sharp, and let the edges go, since you apparently have a choice between 'center-sharp' and 'edge-sharp' at infinity. Link to post Share on other sites More sharing options...
jaapv Posted June 14, 2011 Share #6 Posted June 14, 2011 In other words, they believe it missed focus. This lens has a bit of CFA it seems, which was not necessary a bad thing on film, but may pose a problem on a flat sensor. I never had a problem with it in daily use. It is rather unusual however to focus on infinity with the lens at max aperture in broad daylight, so I may have taken few shots that way. As soon as you stop down a bit the problem will disappear. Link to post Share on other sites More sharing options...
01af Posted June 14, 2011 Share #7 Posted June 14, 2011 Advertisement (gone after registration) That's coherent with the official MTF curves as published in the PDF documents available for download from Leica's home page. At a medium aperture like f/5.6, the image quality is weakest in the Summicron-M 35 mm Asph; it's better in both the Summilux-M 35 mm Asph and the Summarit-M 35 mm. However in the Summarit-M, sharpness drops off slightly more than in the Summicron-m Asph in the farthest corners (but not yet at the edges). So if you can live with a slight drop-off at in the last 1.5 mm of image height then the Summarit-M 35 mm looks like the best 35 mm lens for aerial images. If the far corners are as important as the center then I'm afraid you'll have to use the Summilux-M 35 mm Asph—which of course is an expensive choice when you're going to use it mostly at f/4 or f/5.6. You may also consider the 28 mm lenses (both Elmarit-M Asph and Summicron-M Asph) which have very smooth and even MTF curves across the whole field from the center into the far corners. And oh, one more point to consider—do you actually focus at the ground, or do you simply throw the focus ring at the infinity stop? Maybe the distance is not quite infinity yet ... or the infinity stop on the lens is misadjusted. Link to post Share on other sites More sharing options...
LotharZhou Posted June 14, 2011 Author Share #8 Posted June 14, 2011 Many thanks Jaap, I tried to take shots at various aperture at infinity, still the same, however the strange thing is when I took the lens to solmser and Mr Jacob asked someone to tweak it, it was slightly better, which means there is a way to tune to lens. The photos above are taken after the tweak. Thanks! In other words, they believe it missed focus. This lens has a bit of CFA it seems, which was not necessary a bad thing on film, but may pose a problem on a flat sensor. I never had a problem with it in daily use. It is rather unusual however to focus on infinity with the lens at max aperture in broad daylight, so I may have taken few shots that way. As soon as you stop down a bit the problem will disappear. Link to post Share on other sites More sharing options...
LotharZhou Posted June 14, 2011 Author Share #9 Posted June 14, 2011 BTW, I do get this at different distance, sometimes worse sometimes better, Leica replied me and said they are going to make announcement about this issue. Thanks again! Link to post Share on other sites More sharing options...
ho_co Posted June 14, 2011 Share #10 Posted June 14, 2011 ... Leica replied me and said they are going to make announcement about this issue.... It's an interesting one I hadn't heard about. Fascinating how much we learn about our lenses from our digital cameras! Link to post Share on other sites More sharing options...
charby57 Posted June 14, 2011 Share #11 Posted June 14, 2011 Mmm! Interesting problem. I have the very same problem on my own sample of chrome 35 Summicron asph., serial number #4003465. I have think up to now that I was alone with this phenomenon... Pierre Link to post Share on other sites More sharing options...
LotharZhou Posted June 14, 2011 Author Share #12 Posted June 14, 2011 yeah, good to know someone sharing the same issue, mine is 4100720, bought brand new at Dixons Heathrow airport. Link to post Share on other sites More sharing options...
jaapv Posted June 14, 2011 Share #13 Posted June 14, 2011 Many thanks Jaap, I tried to take shots at various aperture at infinity, still the same, however the strange thing is when I took the lens to solmser and Mr Jacob asked someone to tweak it, it was slightly better, which means there is a way to tune to lens. The photos above are taken after the tweak. Thanks! Yes - they can shift the plane of focus to find the best compromise - just like they do for focus shift. Link to post Share on other sites More sharing options...
okram Posted June 14, 2011 Share #14 Posted June 14, 2011 Let me notice that your sharpening technique is little bit strange. It seems to me that I can draw much more from M8 with this lens (I have a silver one). First thing I did when I bought this lens was a shot at infinity with something detailed at the center, and the recompose to put the same object to all four corners. At f2, of course. Center showed a tad bit more resolution, but negligible. This is a very sharp lens on M8, corner to corner. The only sharper lens I have/had is 75Cron and 50Lux ASPH. 28Cron could be a tad sharper, but lower contrast. I also recommend to turn off all sharpening when comparing, but also to have a look to sharpened files, of course. M Link to post Share on other sites More sharing options...
LotharZhou Posted June 14, 2011 Author Share #15 Posted June 14, 2011 Thanks, I have done nothing special for the sharpening, just a standard PS 60% sharpen, almost for all of my photos. The original image is the same, corners have more resolution than the center circle, I have made hundreds shots with this lens at infinity, more or less the same result. All of my other Leica or Zeiss and CV lens are extremly sharp across the whole frame, it's just this new chrome 2/35 asph a problem. Leica has made it clear it's neither the lens nor the camera's issue, still yet to find a solution for this. My sharpest lens is ZM25/2.8, second CV35/2.5pancake and CV35/1.2 at F2, then the 2/28mm asph. Let me notice that your sharpening technique is little bit strange.It seems to me that I can draw much more from M8 with this lens (I have a silver one). First thing I did when I bought this lens was a shot at infinity with something detailed at the center, and the recompose to put the same object to all four corners. At f2, of course. Center showed a tad bit more resolution, but negligible. This is a very sharp lens on M8, corner to corner. The only sharper lens I have/had is 75Cron and 50Lux ASPH. 28Cron could be a tad sharper, but lower contrast. I also recommend to turn off all sharpening when comparing, but also to have a look to sharpened files, of course. M Link to post Share on other sites More sharing options...
hoppyman Posted June 14, 2011 Share #16 Posted June 14, 2011 Howard, very likely that question was to see if it was possible to provide some extra service for the customer as a priority. (yes, I saw the smiley) For example: when I asked during a Forum meeting visit to Solms on a Friday about booking my M8 in for an upgrade, I was asked when I was leaving Germany. I said Tuesday. Customer Service said your camera will be ready Monday (no express service additional charges) and here is a loan camera to use in the meantime, oh and we checked your lenses for you while you were here today . They are good, we can make them better. Leave them with us and we will service them for free including adjustment to M8 standard and express courier them back to you internationally. All of which they did. Lothar--I like the "When do you leave?" line! ...... Link to post Share on other sites More sharing options...
Patrizio Posted June 16, 2011 Share #17 Posted June 16, 2011 Lothar, My Cron 35 ASPH is very sharp uniformly around the frame but I have your same issue with a chrome Summilux 35 ASPH that is perfectly calibrated for f1.4 but exhibits focus shift at intermediate apertures at all focus distances exactly as you are showing on your samples. It seems like in some Leica lenses the OOF areas in case of wrong focus settings are not uniform as it would seem logical from the concave design of the front element in the Cron or Lux 35. I solved this issue by focusing "closer" (a couple on mm on the focus ring) than showed in the RF whenever above f1.4 and in that case the frame appears uniformly focused. This uncomfortable tweak helps, in my case, at infinity as well. In this case, to achieve the most uniform sharpness along the sensor I have to reach the infinity stop on the focus ring and then go back with the same focus tab of a small increment. Try to see if the problem is only at infinity or at all distances and that might signify something more evident for the lens behaviour and an eventual RF ca,ibration ofnyour M8 Best, Pat Link to post Share on other sites More sharing options...
LotharZhou Posted June 17, 2011 Author Share #18 Posted June 17, 2011 Thanks Pat, it's interesting to know that the Lux is showing this problem as well, I have just got the lens back from Solmser, will test it later and focus a little closer at infinity, see if it helps! Thanks for the advice and I will let all of you know. Lothar, My Cron 35 ASPH is very sharp uniformly around the frame but I have your same issue with a chrome Summilux 35 ASPH that is perfectly calibrated for f1.4 but exhibits focus shift at intermediate apertures at all focus distances exactly as you are showing on your samples. It seems like in some Leica lenses the OOF areas in case of wrong focus settings are not uniform as it would seem logical from the concave design of the front element in the Cron or Lux 35. I solved this issue by focusing "closer" (a couple on mm on the focus ring) than showed in the RF whenever above f1.4 and in that case the frame appears uniformly focused. This uncomfortable tweak helps, in my case, at infinity as well. In this case, to achieve the most uniform sharpness along the sensor I have to reach the infinity stop on the focus ring and then go back with the same focus tab of a small increment. Try to see if the problem is only at infinity or at all distances and that might signify something more evident for the lens behaviour and an eventual RF ca,ibration ofnyour M8 Best, Pat Link to post Share on other sites More sharing options...
LotharZhou Posted June 17, 2011 Author Share #19 Posted June 17, 2011 great, the trick worked, I focus at distance object and spin the focus ring back a little and the image is sharp! Many thanks guys! Link to post Share on other sites More sharing options...
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