Adalsteinn S.H. Posted October 1, 2017 Share #1 Posted October 1, 2017 Advertisement (gone after registration) I have a question for you all that I hope that you can help me with. I just bought a used 35mm Summicron ASPH (no coded) for my MP240 and have set Lens Detection to Manual and 35 f/2 ASPH (my lens is a 1182). When I finally had an opportunity to go out shooting this morning I used just to apertures, f/2,0 and f/4,0. But when I had a look at the images I shot I noticed that the apertures seemed all over the place showing f/3,4 , f/2,8 and even f/16 (took for example numerous shots at one spot and all of them show ISO200 - f/16 - 1/500 sec in LR). Any idea what is going on here? 1 Quote Link to post Share on other sites More sharing options...
Advertisement Posted October 1, 2017 Posted October 1, 2017 Hi Adalsteinn S.H., Take a look here Why aperture changes automatically on my 35mm Cron. I'm sure you'll find what you were looking for!
jdlaing Posted October 1, 2017 Share #2 Posted October 1, 2017 It has to do with the camera guessing at the apertures with relationship to metering. The camera "guesses" at the aperture based on the brightness of the image. There is no electronic connection between the lens and camera and the camera gas no idea what aperture is set. The registration in the menu where you pic the lens records the lens mounted in exif and on some lenses allows for minor corrections. 1 Quote Link to post Share on other sites More sharing options...
Adalsteinn S.H. Posted October 1, 2017 Author Share #3 Posted October 1, 2017 It has to do with the camera guessing at the apertures with relationship to metering. The camera "guesses" at the aperture based on the brightness of the image. There is no electronic connection between the lens and camera and the camera gas no idea what aperture is set. The registration in the menu where you pic the lens records the lens mounted in exif and on some lenses allows for minor corrections. Thanks for your swift reply. So the only way to counter this is to have the lens coded? Quote Link to post Share on other sites More sharing options...
pop Posted October 1, 2017 Share #4 Posted October 1, 2017 Coding the lens will have no effect. The camera simply does not know the current aperture value of the lens. 1 Quote Link to post Share on other sites More sharing options...
Adalsteinn S.H. Posted October 1, 2017 Author Share #5 Posted October 1, 2017 Coding the lens will have no effect. The camera simply does not know the current aperture value of the lens. Not quite sure if I follow you. Does this apply to all lenses for all M Leica's as there is no electronic connector in any of them? 1 Quote Link to post Share on other sites More sharing options...
a.noctilux Posted October 1, 2017 Share #6 Posted October 1, 2017 M 240 (and co) has a sensor near the front logo to measure the light and compare this to the amount of light reaching the inside light sensor. Coding or not a lens, no difference in the f stop calculated. In M10, Leica don't offer that "F Stop in EXIF" anymore. 1 Quote Link to post Share on other sites More sharing options...
stephan54 Posted October 1, 2017 Share #7 Posted October 1, 2017 Advertisement (gone after registration) The M10 behaves like that with all lenses. Some older models 'guess' the aperture. 1 Quote Link to post Share on other sites More sharing options...
Tomek Posted October 1, 2017 Share #8 Posted October 1, 2017 Please refer to „135/f3.4 APO M lens 6-bit code question” https://r.tapatalk.com/shareLink?share_fid=3888&share_tid=273726&share_pid=3300668&url=https://www.l-camera-forum.com/index.php?/topic/273726-135-f3%2E4-APO-M-lens-6-bit-code-question/page__view__findpost__p__3300668&share_type=thttps://r.tapatalk.com/shareLink?share_fid=3888&share_tid=273726&share_pid=3300668&url=https://www.l-camera-forum.com/index.php?/topic/273726-135-f3%2E4-APO-M-lens-6-bit-code-question/page__view__findpost__p__3300668&share_type=t for more information 1 Quote Link to post Share on other sites More sharing options...
Adalsteinn S.H. Posted October 1, 2017 Author Share #9 Posted October 1, 2017 Ok, got it. Phew, nothing wrong with my 35! Thanks guys for your help here. 1 Quote Link to post Share on other sites More sharing options...
a.noctilux Posted October 1, 2017 Share #10 Posted October 1, 2017 Nothing wrong with your lens or your M-P 240. No "F Stop guessing" anymore in M10... FYI link to M10 FAQ : https://www.l-camera-forum.com/topic/269389-my-images-do-not-display-the-f-stop-data-is-there-a-problem-with-my-m10/ 1 Quote Link to post Share on other sites More sharing options...
jdlaing Posted October 1, 2017 Share #11 Posted October 1, 2017 Thanks for your swift reply. So the only way to counter this is to have the lens coded? Lens coding will still not record aperture set on the lens. There is no way for the lens to tell the camera what the aperture set is. 1 Quote Link to post Share on other sites More sharing options...
jdlaing Posted October 1, 2017 Share #12 Posted October 1, 2017 Not quite sure if I follow you. Does this apply to all lenses for all M Leica's as there is no electronic connector in any of them? Correct. 1 Quote Link to post Share on other sites More sharing options...
jmahto Posted October 2, 2017 Share #13 Posted October 2, 2017 I have a question for you all that I hope that you can help me with. I just bought a used 35mm Summicron ASPH (no coded) for my MP240 and have set Lens Detection to Manual and 35 f/2 ASPH (my lens is a 1182). When I finally had an opportunity to go out shooting this morning I used just to apertures, f/2,0 and f/4,0. But when I had a look at the images I shot I noticed that the apertures seemed all over the place showing f/3,4 , f/2,8 and even f/16 (took for example numerous shots at one spot and all of them show ISO200 - f/16 - 1/500 sec in LR). Any idea what is going on here? Just to be clear, actual aperture used (which affects DOF and exposure) is what you set on the lens..... only the recorded aperture is changing since it is a guess (M10 doesn't even try to guess, leaving it blank in EXIF). Quote Link to post Share on other sites More sharing options...
happymac Posted October 2, 2017 Share #14 Posted October 2, 2017 Just to be clear, actual aperture used (which affects DOF and exposure) is what you set on the lens..... only the recorded aperture is changing since it is a guess (M10 doesn't even try to guess, leaving it blank in EXIF). Most of M10 users claim for bringing back this feature with one of the next firmware updates! Quote Link to post Share on other sites More sharing options...
UliWer Posted October 2, 2017 Share #15 Posted October 2, 2017 Most of M10 users claim for bringing back this feature with one of the next firmware updates! ... and the update will enclose an automatic link to threads like this one. 2 Quote Link to post Share on other sites More sharing options...
DaveNC Posted October 2, 2017 Share #16 Posted October 2, 2017 old school solution - jot down details in your notebook after each image is snapped. 1 Quote Link to post Share on other sites More sharing options...
Leicaiste Posted October 2, 2017 Share #17 Posted October 2, 2017 Coding the lens will have no effect. The camera simply does not know the current aperture value of the lens. It is not totally true. The coding will inform the camera of the maximum and minimum apertures available on the lens in use. Which means, as an example, that a coded Summicron will never show f1,4 as the aperture used, which can happen with a non coded lens. 1 Quote Link to post Share on other sites More sharing options...
jmahto Posted October 3, 2017 Share #18 Posted October 3, 2017 It is not totally true. The coding will inform the camera of the maximum and minimum apertures available on the lens in use. Which means, as an example, that a coded Summicron will never show f1,4 as the aperture used, which can happen with a non coded lens. You have too much confidence in Leica FW coders. Quote Link to post Share on other sites More sharing options...
Leicaiste Posted October 3, 2017 Share #19 Posted October 3, 2017 You have too much confidence in Leica FW coders. Care to explain? Quote Link to post Share on other sites More sharing options...
Adalsteinn S.H. Posted October 3, 2017 Author Share #20 Posted October 3, 2017 One thing that I do however notice now when shooting JPB+DNG it that the jpg's get corrected for vignetting but the DNG's not. Is it safe for me to conclude that the 6-bit coding does nothing for the DNG's? Quote Link to post Share on other sites More sharing options...
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