matlep Posted July 11, 2016 Share #1 Posted July 11, 2016 Advertisement (gone after registration) Have a look at the attached file. A shot of my black suitcase shot with the M 262 and the Leica Q. The M 262 looks like it renders the black the same way that the M8 did before the UV/IR cut filter was applied. Normal or not? I would say not, but I would like a second opinion. 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/262436-m-262-colour/?do=findComment&comment=3077090'>More sharing options...
Advertisement Posted July 11, 2016 Posted July 11, 2016 Hi matlep, Take a look here M (262) colour. I'm sure you'll find what you were looking for!
matlep Posted July 11, 2016 Author Share #2 Posted July 11, 2016 And also. Have a look at this. Q screen on top, M 262 bottom. The M 262 screen clearly has a yellow tint. Did I get a lemon of a camera? 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! 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/262436-m-262-colour/?do=findComment&comment=3077092'>More sharing options...
jaapv Posted July 11, 2016 Share #3 Posted July 11, 2016 That is completely normal. There are differences in colour cast between LCD screens, and it is well known that the M 240 has some IR sensitivity, albeit not as much as the M8 by far. I will use an IR filter on mine as a matter of routine whenever IR light is present in significant amounts. 2 Quote Link to post Share on other sites More sharing options...
matlep Posted July 11, 2016 Author Share #4 Posted July 11, 2016 Thanks Jaap! Never noticed the magenta/IR sensitivity on my old M 240(s) and the 20.000+ shot I took with them. But maybe thats because I never looked for it? The scree bothers me a bit, I have had a M-P and a regular M 240 together with my Q, but they where not different in LCD colour. It is not a biggie, but a bit annoying when using side by side. Quote Link to post Share on other sites More sharing options...
ajmarton1 Posted July 11, 2016 Share #5 Posted July 11, 2016 Interesting. I have the M-P and Q. But I primarily shot B&W so I have the LCDs setup for B&W. That may be one solution. 1 Quote Link to post Share on other sites More sharing options...
ralphh Posted July 13, 2016 Share #6 Posted July 13, 2016 I'm not sure if it's related, but if I shoot with my lens cap on with my 240 and boost it a few stops so it's not just a black frame, the resulting frame is red. Is that IR related, or just a slit oh overactive red channel? Quote Link to post Share on other sites More sharing options...
jaapv Posted July 13, 2016 Share #7 Posted July 13, 2016 Advertisement (gone after registration) How can it be IR related with the lens cap on? You probably clipped the red channel. Quote Link to post Share on other sites More sharing options...
ralphh Posted July 13, 2016 Share #8 Posted July 13, 2016 Well that's kinda what I was thinking, but darkness is usually pretty neutral - implies an overactive red channel, no? Quote Link to post Share on other sites More sharing options...
Exodies Posted July 13, 2016 Share #9 Posted July 13, 2016 What do you see when you look at the sun through the lens cap? 1 Quote Link to post Share on other sites More sharing options...
ralphh Posted July 13, 2016 Share #10 Posted July 13, 2016 Nothing, why? Quote Link to post Share on other sites More sharing options...
Exodies Posted July 13, 2016 Share #11 Posted July 13, 2016 I thought it might have a red tint 1 Quote Link to post Share on other sites More sharing options...
jaapv Posted July 13, 2016 Share #12 Posted July 13, 2016 Well that's kinda what I was thinking, but darkness is usually pretty neutral - implies an overactive red channel, no? You have double the number of green pixels in a Bayer pattern; Being opposite red, I can imagine the colour tipping when you increase exposure dramatically with the pixels filled at 0%. Have a look what happens when you are in LAB. Quote Link to post Share on other sites More sharing options...
ralphh Posted July 14, 2016 Share #13 Posted July 14, 2016 (edited) How do you get red as opposite to green in a 3 colour system? Where's blue in that? Isn't cyan the opposite of red? Side point - there are equal blue and red pixels, yet blue exposure is the same as green. Edited July 14, 2016 by ralphh Quote Link to post Share on other sites More sharing options...
jaapv Posted July 14, 2016 Share #14 Posted July 14, 2016 The underlying engine of Photoshop is based on CIELAB D50, which means that the A channel is red/green. (Source: Real World Color Management by Bruce Frazer, Chris Murphy and Fred Bunting) So the colour imbalance will manifest itself in the A channel. Quote Link to post Share on other sites More sharing options...
ralphh Posted July 14, 2016 Share #15 Posted July 14, 2016 (edited) I'm not using photohsop for this, I'm using LR, which I had understood is RGB based Edited July 14, 2016 by ralphh 1 Quote Link to post Share on other sites More sharing options...
jaapv Posted July 14, 2016 Share #16 Posted July 14, 2016 Lightroom IS Photoshop with a different shell. The underlying software is the same. As it is the profile connecting space, I think it is likely that all raw developers use LAB at some point. Quote Link to post Share on other sites More sharing options...
ralphh Posted July 14, 2016 Share #17 Posted July 14, 2016 (edited) So you're saying that even if the sensor records the same amount of red and blue, LR will mistakenly make red because there are more green pixels? Including showing a histogram with a red peak significantly ahead of blue and green? I really don't buy that, sorry. Edited July 14, 2016 by ralphh Quote Link to post Share on other sites More sharing options...
ralphh Posted July 14, 2016 Share #18 Posted July 14, 2016 (edited) Also, it seems very unlikely the camera is making the same lab mode mistake rather than basing it's histogram on the actual sensor output and getting red vs blue incorrect, though I suppose it's possible it makes no sense to me. Note that both LR and camera histograms record more red than blue without boosting exposure. I just can't see the red colour with my eyes without boosting it. 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! Edited July 14, 2016 by ralphh 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/262436-m-262-colour/?do=findComment&comment=3078671'>More sharing options...
jaapv Posted July 14, 2016 Share #19 Posted July 14, 2016 LAB is the profile connecting space, so chances are that the in-camera raw conversion software is using it as well. We are talking about an image that is 100% underexposed, so all pixels record 0% fill. I would hardly call any weird effects when you boost exposure dramatically a mistake. Quote Link to post Share on other sites More sharing options...
ralphh Posted July 14, 2016 Share #20 Posted July 14, 2016 (edited) The pixels are not going to output 0% because of noise. And noise should be equally distributed - in theroy. I can see the red tint in the histogram without any boosting or other manipulations, so forget that. Shadows at ISO6400 long exposures are always red. But either way, I would not call red shadows in an 8 second ISO 6400 shot a problem. Even if I did, it'd be someone else's problem - I generally shoot at ISO 200, 1/125th or faster. But as a professional photographer with a degree in software engineering, the why still has more than a passing interest to me. If indeed the sensor is outputting equal red and blue and the demosaicing algorithm is taking that and outputting twice as much red than blue, then yes that is a mistake. If it's taking the output from an RGB device, and saving it into an RGB file, but making said mistake because it's taking a trip via LAB on the way, then that is a silly mistake. You say the M240 is IR sensitive. Well the inside on my lens cap is a scorching 300 kelvin. It is probably emitting some IR light. I'd take that as an explanation. There are other more outside-the-box possibilities like the red dye in the red microlenses is slightly less opaque, and the red photosites are therefor tuned to be slightly more sensitive so a normal image is balanced. In the absence of a signal they'd then produce more noise than the blue or green ones and give the red tint. Edited July 14, 2016 by ralphh Quote Link to post Share on other sites More sharing options...
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