MikeMyers Posted March 7, 2020 Author Share #81 Posted March 7, 2020 (edited) Advertisement (gone after registration) 1 hour ago, jaapv said: .......A sensor is the opposite of negative film. Whereas film can block the shadows (i.e. no halide crystals have been activated, so less light will not make a difference), a sensor will reach a limit of photons it can absorb. So the left hand side is a "soft" limit, i.e. the photon-induced signal drowns in random noise, and the right-hand side a "hard" limit, i.e. details will be recorded up to 100% of saturation and not one photon more....... What all of you have said is fascinating. For me, a lot of things now make sense that I didn't understand correctly before. Talking only about me, I guess this is the end of my using "image compensation" and "Auto ISO". That leaves me permanently in (M)anual mode. It also leaves me paying more attention to the histogram, realizing that the right side is a "hard" limit, but the left side is sort of fuzzy. Maybe some day Leica will design a new histogram display that implies this, rather than the old one as was used for film. Assuming that I am now going to attempt to use ISO 200 as a starting point for everything, and use the aperture only to control depth of field, I'll be learning how to select an appropriate shutter speed. Jeff, if you have time, it would be interesting to learn how you use the tone curve to improve M10 photos. I know I'm in the dark, as the most important thing I use the tone curve for, is to give an image some more "punch". Since that's post processing, maybe there is a better forum on this site to post it. I've barely scratched the surface of what's available here, and from what 'jaapv' wrote, I need to be looking for the appropriate place to ask several of my questions/photos. (....and I wish people who view my photos would start telling me how to improve them. I won't be getting upset, I'll be saying "thank you".) Gosh, a few days ago I posted this thread to help my understand something that I thought was very simple. I guess it wasn't so simple, and as a result I' learned things that I was completely oblivious to in the past..... Edited March 7, 2020 by MikeMyers typo 1 Quote Link to post Share on other sites More sharing options...
Advertisement Posted March 7, 2020 Posted March 7, 2020 Hi MikeMyers, Take a look here Exposure Compensation Question. I'm sure you'll find what you were looking for!
Dennis Posted March 7, 2020 Share #82 Posted March 7, 2020 Excuse me for a second the intromission. Does the M10 is ISOLess? Which are the ISO we can use with this characteristic? Because, if I understood correctly, if let's say the range of the ISO-Less M10 is from 100 to 800 iso, I could shoot in manual but with Auto Iso (with max iso set on 800) and have great result in post-processing without visible noise. Am I right? That's why I would love to know the secret iso numbers of the M10 🤣 I learned a lot reading this post, thank you for sharing Quote Link to post Share on other sites More sharing options...
farnz Posted March 7, 2020 Share #83 Posted March 7, 2020 Hi Mike, I hope I can explain a couple of things for you that have become a little confused throughout this thread: 1. Higher ISO values increasing the sensor's sensitivity to light. No, they don't. The sensor is made of thousands of photodiodes whose joy in life is to take radiant energy (photons in the visible spectrum) and turning them into electrical voltages that can be measured and converted into a digital signal by an ADC (Analog to Digital Convertor). Photodiodes have a sensitivity at birth that does not change (well perhaps it degrades a tad as they die) so a sensor's sensitivity is set and ISO cannot change it. What increasing the ISO does is to amplify the output from the sensor so that the voltage fed into the ADC is larger and therefore a 'brighter' digital signal is produced. The amplifier is a wide-band, analog device, which means that it amplifies all of the analog frequencies (wavelengths if you prefer) at its input by the same amount. This means that it will amplify any noise frequencies by the same amount as it amplifies the signal (picture) frequencies. But as the ISO is increased the SNR (signal to noise ratio) reduces because you're starting to scoop the coffee grounds at the bottom of the cup. The higher the ISO, the lower you dig and the more coffee grounds (noise) you scoop proportional to the actual coffee (picture information) that you're feeding into the amplifier. So as ISO increases so the SNR decreases and pictures end up with ISO noise. Meanwhile the sensitivity of the sensor remains the same. 2. Clipping. If you clip the right hand edge of your histogram with a camera with a colour sensor then all is not necessarily lost. This is because the camera is capturing data in three colour channels: red, green and blue. When the histogram indicates that the highlights are just clipped it's actually telling you that the highlights are clipped in at least one of the channels. But not necessarily in all of the channels so post processing software will be able to rescue detail in the other channels that are not clipped by, for example, the Highlight slider in LR or Adobe Camera Raw. Commonly the blue channel clips first but there's often little picture information in the blue channel anyway so the red and green channels can be used to restore the picture information. Obviously if there is heavy overexposure then the highlights in all channels will be blown and there will be no picture information available to be retrieved. As Jaapv mentioned earlier, the same occurs with the left-hand end of the histogram, ie the shadow information. But there is much more detail that can be retrieved from 'blown shadows' with Leica cameras because Leica uses a logarithmic algorithm that retains more information at the shadow end of the scale than at the highlight end. The logarithmic scale assigns higher numerical values to the shadows and thereby balances the data towards the dark end of the 'scale' and, even though the histogram indicates blocked-up shadows, a large amount of detail can be restored through the Shadows slider in, for example, LR or ACR, or in the Highlights and Shadows tool in Photoshop. Pete. 1 Quote Link to post Share on other sites More sharing options...
J.Nordvik Posted March 7, 2020 Share #84 Posted March 7, 2020 In my experience it does not matter if I use ISO 200 or 640, but ISO 800 in camera give better pictures than if I corrected in LR. I use ISO 200 for 95% of my pictures. Never used Auto ISO or exposure compensation. It was interesting to read about how other people take pictures. 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! 1 Quote 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/306905-exposure-compensation-question/?do=findComment&comment=3926828'>More sharing options...
Jeff S Posted March 7, 2020 Share #85 Posted March 7, 2020 (edited) 21 minutes ago, farnz said: 2. Clipping. If you clip the right hand edge of your histogram with a camera with a colour sensor then all is not necessarily lost. This is because the camera is capturing data in three colour channels: red, green and blue. When the histogram indicates that the highlights are just clipped it's actually telling you that the highlights are clipped in at least one of the channels. But not necessarily in all of the channels so post processing software will be able to rescue detail in the other channels that are not clipped by, for example, the Highlight slider in LR or Adobe Camera Raw. Commonly the blue channel clips first but there's often little picture information in the blue channel anyway so the red and green channels can be used to restore the picture information. Obviously if there is heavy overexposure then the highlights in all channels will be blown and there will be no picture information available to be retrieved. Except, of course, on a Monochrom (Bayer-less sensor), which acts more like color slide film: when highlights are blown, they are not recoverable (no color channels). This is where the RAW based histogram on the Monochrom cameras comes in handy. Jeff Edited March 7, 2020 by Jeff S 1 Quote Link to post Share on other sites More sharing options...
farnz Posted March 7, 2020 Share #86 Posted March 7, 2020 (edited) 4 minutes ago, Jeff S said: Except, of course, on a Monochrom (Bayer-less sensor), which acts more like color slide film: when highlights are blown, they are not recoverable. This is where the RAW based histogram on the Monochrom cameras come in handy. Jeff Hence why I specifically wrote "a colour sensor". As far as I know Mike has an M8.2 and a M10 but no mention of a Monochrom so far. Pete. Edited March 7, 2020 by farnz Quote Link to post Share on other sites More sharing options...
Jeff S Posted March 7, 2020 Share #87 Posted March 7, 2020 (edited) Advertisement (gone after registration) 2 minutes ago, farnz said: Hence why I specifically wrote "a colour sensor". As far as I know Mike has an M8.2 and a M10 but no mention of a Monochrom so far. Pete. The explanation was for his benefit and general learning, which in this thread has become much about general knowledge, not merely camera specific. Jeff Edited March 7, 2020 by Jeff S Quote Link to post Share on other sites More sharing options...
IkarusJohn Posted March 7, 2020 Share #88 Posted March 7, 2020 (edited) Great explanations by Jaap and Pete. If you accept that (within reason) the sensor is best left at or about base ISO, and when setting your exposure you need to protect your highlights, what do you do? In some situations, you might use aperture priority, as largely you don't really care too much about shutter speed (you set minimum shutter speed at 1/2f or 4f), or you expose manually. If you do the former, the meter is taking a centre weighted reading.and setting the shutter based on that. In the latter case, you’re using the in-camera meter to set the shutter speed yourself. You could carry a meter, I guess, but the Leica meter is actually good enough, once you get your head around its foibles. To protect highlights, I set the exposure compensation dial to -2/3; not for anything to do with ISO (except for the Monochrom, where I don’t care about ISO). If you NEVER set the shutter dial to A, then it is easy - you dial in half or a full stop of under-exposure from what the meter tells you >🛑 or > in the viewfinder. Whether you do this using exposure compensation or manually doesn’t matter a jot if you never use aperture priority. But, shooting manually, if you do not use exposure compensation, and you set your exposure to 🛑 in the viewfinder, you will clip your highlights. Edited March 7, 2020 by IkarusJohn Quote Link to post Share on other sites More sharing options...
jaapv Posted March 7, 2020 Share #89 Posted March 7, 2020 51 minutes ago, farnz said: Clipping. If you clip the right hand edge of your histogram with a camera with a colour sensor then all is not necessarily lost. This is because the camera is capturing data in three colour channels: red, green and blue. When the histogram indicates that the highlights are just clipped it's actually telling you that the highlights are clipped in at least one of the channels. But not necessarily in all of the channels so post processing software will be able to rescue detail in the other channels that are not clipped by, for example, the Highlight slider in LR or Adobe Camera Raw. Commonly the blue channel clips first but there's often little picture information in the blue channel anyway so the red and green channels can be used to restore the picture information. Obviously if there is heavy overexposure then the highlights in all channels will be blown and there will be no picture information available to be retrieved. Quite correct. Also, as I mentioned, the clipping warning and histogram are based on the in-camera jpg. In practice that means that there is at least 1/2 an EV value leeway. Interestingly, Leica acknowledged this in the MM1, which was their first camera with a really hard right-hand stop, for the reason you mention, by providing a raw histogram. BTW, the quality of the details extrapolated if a (or two) channel(s) are clipped does show quality deterioration. Quote Link to post Share on other sites More sharing options...
Dennis Posted March 7, 2020 Share #90 Posted March 7, 2020 5 minutes ago, IkarusJohn said: If you accept that (within reason) the sensor is best left at or about base ISO Thanks to this post, I understood it. But of course is always not possible, right? I shoot almost 100% available light, personal and work. Most of my photographs have people in, that's why I need at least 1/125 ... I don't want to freeze the action like I were using a flash, but I don't want a blurry image of the main subject. In a situation like this, having a Leica M10 and a Zeiss Biogon 2.8, I decided to shoot at 1/90, F/2.8 and iso 6400 ... I always exposed for the right light, my favorite light. Sometimes for the highlights, sometimes for the mid-tones but usually not for the shadows. 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! In this situation, where I don't want to use any kind of light help (flash or led), where I don't care about the shadows, what you would have done? Maybe the same settings, except the ISO. Maybe 1600 and then recovery two stops in LR? Note: I didn't applied any noise reduction to the image. Jpeg exported from a DNG file. But the noise it's notable. Acceptable for you? I would love to know how to avoid it and have a better dynamic range image. But more than anything, I believe in the right exposure when I'm shooting, and almost do nothing on post-processing. 1 Quote Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! In this situation, where I don't want to use any kind of light help (flash or led), where I don't care about the shadows, what you would have done? Maybe the same settings, except the ISO. Maybe 1600 and then recovery two stops in LR? Note: I didn't applied any noise reduction to the image. Jpeg exported from a DNG file. But the noise it's notable. Acceptable for you? I would love to know how to avoid it and have a better dynamic range image. But more than anything, I believe in the right exposure when I'm shooting, and almost do nothing on post-processing. ' data-webShareUrl='https://www.l-camera-forum.com/topic/306905-exposure-compensation-question/?do=findComment&comment=3926883'>More sharing options...
IkarusJohn Posted March 7, 2020 Share #91 Posted March 7, 2020 I always try to get the best exposure I can in camera. For this image, I would ignore the shadows and expose for the highlights as that’s the detail I would want to retain. I would still keep the ISO as close to 200 as possible. Some curve adjustment in post processing, perhaps darken the shadows and increase contrast slightly. Hard to say much more. Compositionally, the background is very busy, making the subject (the guy on the bars) hard to isolate. A different perspective might make a difference, but probably not possible. I find the background more interesting and atmospheric than the guy on the bars ... Quote Link to post Share on other sites More sharing options...
MikeMyers Posted March 7, 2020 Author Share #92 Posted March 7, 2020 1 hour ago, farnz said: Hi Mike, I hope I can explain a couple of things for you that have become a little confused throughout this thread: 1. Higher ISO values increasing the sensor's sensitivity to light. No, they don't. The sensor is made of thousands of photodiodes whose joy in life is to take radiant energy (photons in the visible spectrum) and turning them into electrical voltages that can be measured and converted into a digital signal by an ADC (Analog to Digital Convertor). Photodiodes have a sensitivity at birth that does not change (well perhaps it degrades a tad as they die) so a sensor's sensitivity is set and ISO cannot change it. What increasing the ISO does is to amplify the output from the sensor so that the voltage fed into the ADC is larger and therefore a 'brighter' digital signal is produced. The amplifier is a wide-band, analog device, which means that it amplifies all of the analog frequencies (wavelengths if you prefer) at its input by the same amount. This means that it will amplify any noise frequencies by the same amount as it amplifies the signal (picture) frequencies. But as the ISO is increased the SNR (signal to noise ratio) reduces because you're starting to scoop the coffee grounds at the bottom of the cup. The higher the ISO, the lower you dig and the more coffee grounds (noise) you scoop proportional to the actual coffee (picture information) that you're feeding into the amplifier. So as ISO increases so the SNR decreases and pictures end up with ISO noise. Meanwhile the sensitivity of the sensor remains the same. 2. Clipping. If you clip the right hand edge of your histogram with a camera with a colour sensor then all is not necessarily lost. This is because the camera is capturing data in three colour channels: red, green and blue. When the histogram indicates that the highlights are just clipped it's actually telling you that the highlights are clipped in at least one of the channels. But not necessarily in all of the channels so post processing software will be able to rescue detail in the other channels that are not clipped by, for example, the Highlight slider in LR or Adobe Camera Raw. Commonly the blue channel clips first but there's often little picture information in the blue channel anyway so the red and green channels can be used to restore the picture information. Obviously if there is heavy overexposure then the highlights in all channels will be blown and there will be no picture information available to be retrieved. As Jaapv mentioned earlier, the same occurs with the left-hand end of the histogram, ie the shadow information. But there is much more detail that can be retrieved from 'blown shadows' with Leica cameras because Leica uses a logarithmic algorithm that retains more information at the shadow end of the scale than at the highlight end. The logarithmic scale assigns higher numerical values to the shadows and thereby balances the data towards the dark end of the 'scale' and, even though the histogram indicates blocked-up shadows, a large amount of detail can be restored through the Shadows slider in, for example, LR or ACR, or in the Highlights and Shadows tool in Photoshop. Pete. I don't know yet how this website/forum works, but I do know I'm going to copy and save what you just wrote up above, and some of what 'jaapv'' wrote, and save/print it for future reference. Rather than it being buried on page #5 of a fascinating discussion, it should go in a more prominent place so more people will learn from it. I have no questions about what you guys wrote, but I do have a few thoughts regarding Leica: 1 - histogram - apparently a colored histogram showing the different channels would be helpful. Would be nice to see a small version in the optical finder, maybe in the top left corner? Also, rename it as "Leicagram", show a hard stop at the right, and a fuzzy stop at the left, and continue the graph to the left of the left stop, indicating that is still useful information. 2 - refer to the ISO numbers as "Brightness (ISO)". Make sure documentation (including user manuals) says that it is increasing or decreasing the brightness of an image. Maybe there is a technical term that already says that. (I suspect that 95% of the people reading this forum are sure that ISO = sensor sensitivity. Needs to be corrected.) 3 - Leica should turn off "exposure compensation' when the user selects manual settings for aperture (always), shutter, and ISO. Also, change the name to "Brightness Compensation". Quote Link to post Share on other sites More sharing options...
MikeMyers Posted March 7, 2020 Author Share #93 Posted March 7, 2020 1 hour ago, farnz said: .......As far as I know Mike has an M8.2 and a M10 but no mention of a Monochrom so far...... I have an old, but working M2, and M3. I have my M8.2 which I used seriously for about half a year, then it sort of got put away, until I returned from India in January. I had decided before I returned that I would put away all my other camera gear, and try to only use the M8.2 camera. The more I used the M8.2, the more I realized that I wanted a Leica that could replace my other gear, so I bought the M10. I can't think of why I would even consider buying a Monochrome, unless/until I start doing a lot more black&white work. (When I was working, it seemed easier to afford expensive new camera gear...) Quote Link to post Share on other sites More sharing options...
jaapv Posted March 7, 2020 Share #94 Posted March 7, 2020 On 3/2/2020 at 5:06 AM, MikeMyers said: After another few days working with the M10, I decided that I am most likely to want to be involved in the shutter speed and aperture, and least likely to be involved in the ISO. The shutter and aperture will have a big effect on my image, and the ISO not so much (usually), So, I set the camera back to auto-ISO, and I pick a shutter speed and an aperture for what I'm trying to do. The camera plays with the ISO, and I verify that the meter reading seems to be acceptable. Back when I shot film, the ASA was fixed, depending on what film I was using. I couldn't always use the shutter and aperture I preferred (although if by magic, I could have have switched films in mid-roll, that would have been great. That's all auto-ISO is doing. I don't know if it's true or not, but I would hope that if I pick the shutter and aperture, and I let the camera select an appropriate ISO, if I also want to use exposure compensation, maybe the camera will apply that the the ISO and leave the shutter and aperture the way I set them. I need to test this, but even if the camera does it differently, if I want to underexpose by one f/stop, one way or another the camera will do it. Maybe auto-ISO is "cheating", but it's the best compromise I can find for me, and I still think I'll feel in charge of the exposure. I used it this way today, and was very happy with everything except my pathetic forgetfulness as to focus. Most of the time I caught it in time, but I need to make it automatic. I was already using zone focusing, but when the subject of the image moved towards me, I should have recognized that I needed to adjust things. I'm still too spoiled by my Nikon cameras. Sorry for being so....... forgetful. I've got far too many years of "bad habits" to break. Serious advice; get away from zone focusing. Yes, it will give you acceptable sharpness in the field you have chosen and is much easier than learning to use a rangefinder. But Leica lenses deserve better. They will be razor sharp in the plane of focus. That gives you the photographic vocabulary to concentrate the attention (AKA focus) on your chosen subject. The only way to achieve the elusive “Leica Look” is precise focus. it is easily done too. When sitting in front of the Telly at night, annoy your wife by practicing , practicing, practicing, instead of being passively bored by the flick machine. 1 Quote Link to post Share on other sites More sharing options...
MikeMyers Posted March 7, 2020 Author Share #95 Posted March 7, 2020 2 minutes ago, jaapv said: Serious advice; get away from zone focusing. Yes, it will give you acceptable sharpness in the field you have chosen and is much easier than learning to use a rangefinder. But Leica lenses deserve better. They will be razor sharp in the plane of focus. That gives you the photographic vocabulary to concentrate the attention (AKA focus) on your chosen subject. The only way to achieve the elusive “Leica Look” is precise focus. It's for a different reason, but I'm already following your advice. The main reason is practice - the only way I think I am going to get good again with the M10 rangefinder is to use it so much that it becomes as natural as tying my shoe laces. I've been focusing on all sorts of stuff, just to do it. Sometimes it's easy, sometimes it's difficult, sometimes I don't know what to do with my hands, and they just get in the way. Like anything else, it means lots of practice, which won't happen unless I force myself to do this. The most difficult focus problem for me, is if there's no single "object" that I can work with. Also, I dislike all the books and articles and threads that say how much more would be in focus by using "zone focusing". To me, that's nonsense. Only things at one specific distance will be "in focus". Other things may appear acceptably sharp, depending on the size of the printed image and the distance that it is viewed at. As for me, I can usually tell where the camera was focused, and the other areas may look "ok", but not as good as if they were in focus. Never thought about it this way before, but yeah, maybe that is a big part of the "Leica Look". .........and for that matter, the eye, viewing the photo, should match the angle of a person's eye viewing the real scene. That's why images from tele or wide angle lenses look distorted. They're not distorted - the person viewing them needs to stand at the correct distance from the print, based on the focal length of the lens that took the photo, and the size of the photo. 1 Quote Link to post Share on other sites More sharing options...
MikeMyers Posted March 7, 2020 Author Share #96 Posted March 7, 2020 55 minutes ago, Dennis said: Thanks to this post, I understood it. But of course is always not possible, right? I shoot almost 100% available light, personal and work. Most of my photographs have people in, that's why I need at least 1/125 ... I don't want to freeze the action like I were using a flash, but I don't want a blurry image of the main subject. In a situation like this, having a Leica M10 and a Zeiss Biogon 2.8, I decided to shoot at 1/90, F/2.8 and iso 6400 ... I always exposed for the right light, my favorite light. Sometimes for the highlights, sometimes for the mid-tones but usually not for the shadows. 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! In this situation, where I don't want to use any kind of light help (flash or led), where I don't care about the shadows, what you would have done? Maybe the same settings, except the ISO. Maybe 1600 and then recovery two stops in LR? Note: I didn't applied any noise reduction to the image. Jpeg exported from a DNG file. But the noise it's notable. Acceptable for you? I would love to know how to avoid it and have a better dynamic range image. But more than anything, I believe in the right exposure when I'm shooting, and almost do nothing on post-processing. Regarding your photo, I think your exposure is perfect! I think you nailed it. If it was me, I'd have cropped out a lot of the distracting stuff at the right, but the main part of your photo is awesome. I like that every place I look, there is more to be seen, and it's plenty sharp. Just the "stuff" at the right seems like there's too much of it, and my eye drifts over there to see what I can find..... 1 Quote Link to post Share on other sites More sharing options...
farnz Posted March 7, 2020 Share #97 Posted March 7, 2020 40 minutes ago, MikeMyers said: Make sure documentation (including user manuals) says that it is increasing or decreasing the brightness of an image. Maybe there is a technical term that already says that. Indeed there is, Mike: "luminance". Pete. 1 Quote Link to post Share on other sites More sharing options...
Dennis Posted March 7, 2020 Share #98 Posted March 7, 2020 1 hour ago, MikeMyers said: I suspect that 95% of the people reading this forum are sure that ISO = sensor sensitivity. Needs to be corrected I was in the 95%. I wasn't sure, but suspect it about it 🙂 I learned something huge today. I will do some tests, for sure. Thank you Mike and Ikarus for the feedbacks. 1 Quote Link to post Share on other sites More sharing options...
Jeff S Posted March 7, 2020 Share #99 Posted March 7, 2020 This old article by Ctein over at TOP includes suggestions and illustrations (including curve adjustment) to avoid blowing highlights. https://theonlinephotographer.typepad.com/the_online_photographer/2011/10/expose-to-the-right-is-a-bunch-of-bull.html Jeff Quote Link to post Share on other sites More sharing options...
Dennis Posted March 7, 2020 Share #100 Posted March 7, 2020 I'm still a little confused. Can someone please, explaining in a few simple words, what is here happening with the M10, M10M and Nikon D5? 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! How do I read it? The Nikon D5 at 100 iso, has worst details and noise, than a M10? Anyway, it looks like that with the M10, between 800 and 20,000 is having the "same" performance ... Is this iSO less? Please help me to clarify it, it would be awesome. Quote Link to post Share on other sites Simply register for free here – We are always happy to welcome new members! How do I read it? The Nikon D5 at 100 iso, has worst details and noise, than a M10? Anyway, it looks like that with the M10, between 800 and 20,000 is having the "same" performance ... Is this iSO less? Please help me to clarify it, it would be awesome. ' data-webShareUrl='https://www.l-camera-forum.com/topic/306905-exposure-compensation-question/?do=findComment&comment=3927034'>More sharing options...
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