blackdot Posted February 19, 2021 Share #1 Posted February 19, 2021 Advertisement (gone after registration) Forgive me if this super basic, but I'm not finding a clear with answer with my choice of keywords. If I turn on lens detection on my M246, it doesn't seem to do anything vs leaving it off with my new (to me) 21mm Super Elmar. I noticed the latest Leica firmware added profiles also for my pre-asph 35mm Summilux, and there is one for my v3 Summicron 50. Do these settings actually alter the RAW image data in any way, or is it just for keeping track of what lens you use? Thanks. Quote Link to post Share on other sites More sharing options...
Advertisement Posted February 19, 2021 Posted February 19, 2021 Hi blackdot, Take a look here Lens Detection - What Does It Do?. I'm sure you'll find what you were looking for!
blackdot Posted February 19, 2021 Author Share #2 Posted February 19, 2021 Also... i noticed that although Capture One does list a number of Leica lenses, it does not show the "manufacturer profile" option for my M246. Does this mean the lens correction information from the camera is thrown out anyway? Quote Link to post Share on other sites More sharing options...
lct Posted February 19, 2021 Share #3 Posted February 19, 2021 2 hours ago, blackdot said: If I turn on lens detection on my M246, it doesn't seem to do anything vs leaving it off with my new (to me) 21mm Super Elmar. I noticed the latest Leica firmware added profiles also for my pre-asph 35mm Summilux, and there is one for my v3 Summicron 50. Do these settings actually alter the RAW image data in any way, or is it just for keeping track of what lens you use? I have no experience with the M246 but there are two ways of turning lens detection on with my M240: "Automatic" and "Manual". Which one did you choose if any? Also, are your lenses 6-bit coded? Just to understand your issue. Quote Link to post Share on other sites More sharing options...
blackdot Posted February 19, 2021 Author Share #4 Posted February 19, 2021 Just now, lct said: I have no experience with the M246 but there are two ways of turning lens detection on with my M240: "Automatic" and "Manual". Which one did you choose if any? Also, are your lenses 6-bit coded? Just to understand your issue. This lens (the Super Elmar) is coded and was successfully detected automatically. Not really thinking this is an issue, just trying to understand how the system works, as I am still relatively new to digital (after resisting for decades, hiding out in my darkroom with my Focomat :).) Quote Link to post Share on other sites More sharing options...
lct Posted February 19, 2021 Share #5 Posted February 19, 2021 OK then the camera should keep track of your Super Elmar until you change the lens or choose another lens profile through the menu. Quote Link to post Share on other sites More sharing options...
blackdot Posted February 19, 2021 Author Share #6 Posted February 19, 2021 Just now, lct said: OK then the camera should keep track of your Super Elmar until you change the lens or choose another lens profile through the menu. I understand that part, but what does that actually do? Quote Link to post Share on other sites More sharing options...
lct Posted February 19, 2021 Share #7 Posted February 19, 2021 Advertisement (gone after registration) Depends on the camera. On M cameras, it corrects mainly for color shift issues (aka "red edge" on some WA lenses) and mentions the name of the lens in the exif data. 1 Quote Link to post Share on other sites More sharing options...
Jeff S Posted February 20, 2021 Share #8 Posted February 20, 2021 Corrects for color-vignetting issues, which apply primarily to some wide angle lenses on digital Ms, and are difficult to address in post. Not really an issue with film bodies. Of course EXIF data can also be useful for longer focal lengths. Jeff Quote Link to post Share on other sites More sharing options...
blackdot Posted February 20, 2021 Author Share #9 Posted February 20, 2021 7 minutes ago, Jeff S said: Corrects for color-vignetting issues, which apply primarily to some wide angle lenses on digital Ms, and are difficult to address in post. Not really an issue with film bodies. Of course EXIF data can also be useful for longer focal lengths. Jeff Thanks. So, is this automatically baked into the DNG? I tried a very exciting shot of a white wall both with and without the lens detection with my 21, and both images appear identical in Capture One. There is falloff (which I don't mind, honestly. But if it were in color and shifted, I might), and C1 provides a lens profile to handle it. But was that profile embedded in the DNG from the camera? I don't think it was, since every other manufacturer is listed as an option as well. Quote Link to post Share on other sites More sharing options...
Jeff S Posted February 20, 2021 Share #10 Posted February 20, 2021 See relevant FAQ.. https://us.leica-camera.com/Photography/Leica-M/Frequently-asked-questions/(offset)/30 This is different from software profiles that may correct for distortions, etc. Jeff Quote Link to post Share on other sites More sharing options...
blackdot Posted February 20, 2021 Author Share #11 Posted February 20, 2021 3 minutes ago, Jeff S said: See relevant FAQ.. https://us.leica-camera.com/Photography/Leica-M/Frequently-asked-questions/(offset)/30 This is different from software profiles that may correct for distortions, etc. Jeff Ok, so at what point in the process is this embedded information applied as a correction? Quote Link to post Share on other sites More sharing options...
Jeff S Posted February 20, 2021 Share #12 Posted February 20, 2021 Never my interest. Some here will know and care. Jeff Quote Link to post Share on other sites More sharing options...
mmradman Posted February 20, 2021 Share #13 Posted February 20, 2021 My understanding is that lens detection is more relevant to Colour M cameras, less so to Monochrom as no colour information is recorded, only luminance. Colour M may struggle with lens designed for film where light rays hit sensor edge at angles that produce colour anomalies, infamous “Italian Flag” syndrome or Red-White-Green pattern, white bing middle of the sensor. As all Mono models are derived from Colour counterparts lens detection is there to provide audit trail of lens used via Exif. For those who use auto ISO and auto exposure (I do sometime) one can select shutter speed to be fraction of the focal length, my setting is 1/4 - for instance with 50mm lens desired exposure is 1/200 sec or faster. To achieve this camera need to know what lens is attached, 6-bit coding to the rescue. Quote Link to post Share on other sites More sharing options...
blackdot Posted February 20, 2021 Author Share #14 Posted February 20, 2021 5 hours ago, mmradman said: My understanding is that lens detection is more relevant to Colour M cameras, less so to Monochrom as no colour information is recorded, only luminance. Colour M may struggle with lens designed for film where light rays hit sensor edge at angles that produce colour anomalies, infamous “Italian Flag” syndrome or Red-White-Green pattern, white bing middle of the sensor. As all Mono models are derived from Colour counterparts lens detection is there to provide audit trail of lens used via Exif. For those who use auto ISO and auto exposure (I do sometime) one can select shutter speed to be fraction of the focal length, my setting is 1/4 - for instance with 50mm lens desired exposure is 1/200 sec or faster. To achieve this camera need to know what lens is attached, 6-bit coding to the rescue. Thanks. That explains why i'm not seeing any difference at first. I wasn't sure if I needed to do something in post to implement the corrections. I remembered that there is a shading correction setting and after toggling that on, I can now see a difference between detection on vs off (on the lcd anyway - didn't open in C1 yet). Quote Link to post Share on other sites More sharing options...
Jeff S Posted February 20, 2021 Share #15 Posted February 20, 2021 We did say color-vignetting. 😉 Jeff Quote Link to post Share on other sites More sharing options...
Anakronox Posted February 23, 2021 Share #16 Posted February 23, 2021 The EXIF data for the lens (when coded) and any other adjustments made based on the lens are embedded in the raw. Your post-processing software reads these tags and makes adjustments. This is why C1 and LR know what lens you’ve used and can apply a profile automatically. With color digital Leicas, color shifts and casts are baked into the raw by the camera and as far as I’m aware can’t be changed in post. Quote Link to post Share on other sites More sharing options...
blackdot Posted February 23, 2021 Author Share #17 Posted February 23, 2021 Just now, Anakronox said: The EXIF data for the lens (when coded) and any other adjustments made based on the lens are embedded in the raw. Your post-processing software reads these tags and makes adjustments. This is why C1 and LR know what lens you’ve used and can apply a profile automatically. With color digital Leicas, color shifts and casts are baked into the raw by the camera and as far as I’m aware can’t be changed in post. Thanks. I picked up an M10 the other day, and see what's happening much more clearly now. The M246 lets you defeat the vignetting correction, so I wasn't seeing anything happening and thought it required further action from me. Quote Link to post Share on other sites More sharing options...
Herr Barnack Posted February 23, 2021 Share #18 Posted February 23, 2021 (edited) On 2/19/2021 at 9:07 PM, Jeff S said: See relevant FAQ.. https://us.leica-camera.com/Photography/Leica-M/Frequently-asked-questions/(offset)/30 This is different from software profiles that may correct for distortions, etc. Jeff I would like to jump in here with a couple of questions. I read the FAQ about 6 bit coding but there was no mention of correcting for purple fringing. It seems that purple fringing is a separate issue/problem apart from color shift in wide lenses - is that the case? How is purple fringing corrected? Edited February 23, 2021 by Herr Barnack Quote Link to post Share on other sites More sharing options...
Jeff S Posted February 23, 2021 Share #19 Posted February 23, 2021 (edited) 33 minutes ago, Herr Barnack said: I would like to jump in here with a couple of questions. I read the FAQ about 6 bit coding but there was no mention of correcting for purple fringing. It seems that purple fringing is a separate issue/problem apart from color shift in wide lenses - is that the case? How is purple fringing corrected? Separate issue... I correct in PP as best as possible if it’s disturbing. Best to know your gear and shooting conditions/techniques. Jeff Edited February 23, 2021 by Jeff S Quote Link to post Share on other sites More sharing options...
lct Posted February 23, 2021 Share #20 Posted February 23, 2021 6-bit coding does not correct for purple fringing. Quote Link to post Share on other sites More sharing options...
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