MSR_Leica Posted August 19, 2023 Share #1 Posted August 19, 2023 Advertisement (gone after registration) Hi, does anyone knows if the Leica Q is ISO invariant ? I know eg the Sony A7 III is and can be seen on this graph, the sweet spot is at iso 640. It seems like the Leica Q is at iso 400 Br Mikael 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/381073-leica-q-iso-invariance/?do=findComment&comment=4838848'>More sharing options...
Advertisement Posted August 19, 2023 Posted August 19, 2023 Hi MSR_Leica, Take a look here Leica Q iso invariance. I'm sure you'll find what you were looking for!
SrMi Posted August 19, 2023 Share #2 Posted August 19, 2023 I use Input-referred Read Noise vs. ISO graph to determine "ISO invariance" (look for flatness of graph). The Q's graph indicates that Q is pretty ISO invariant starting at ISO 400 Link to post Share on other sites More sharing options...
eriepa Posted August 20, 2023 Share #3 Posted August 20, 2023 (edited) 21 hours ago, SrMi said: I use Input-referred Read Noise vs. ISO graph to determine "ISO invariance" (look for flatness of graph). The Q's graph indicates that Q is pretty ISO invariant starting at ISO 400 Please advise as I am new at trying to decipher these charts. The Leica Q “real” ISO settings apparently are 100, 200, 400, 800, 1600, 3200, and 6400. Higher ISOs are not “real”. The Leica Q sensor appears to be ISO-invariant from ISO 400 to ISO 6400. Past that point, I assume it’s probably better to raise brightness in post not in the camera. Finally, there also seems to be a rather sharp drop-off in dynamic range after ISO 400 and that needs to be considered as well. Am I on the right track here? Thanks! Edited August 20, 2023 by eriepa Link to post Share on other sites More sharing options...
SrMi Posted August 20, 2023 Share #4 Posted August 20, 2023 3 hours ago, eriepa said: Please advise as I am new at trying to decipher these charts. The Leica Q “real” ISO settings apparently are 100, 200, 400, 800, 1600, 3200, and 6400. Higher ISOs are not “real”. The Leica Q sensor appears to be ISO-invariant from ISO 400 to ISO 6400. Past that point, I assume it’s probably better to raise brightness in post not in the camera. Finally, there also seems to be a rather sharp drop-off in dynamic range after ISO 400 and that needs to be considered as well. Am I on the right track here? Thanks! You got it right for ISOs. Real ISO is from ISO 100 to 6400. Looking at the DR graph (PDR vs. ISO), you will see only a gradual drop-off in the dynamic range. The dual conversion gain lowers the read noise at ISO 400 and raises the DR. Theoretically, you are better off shooting at ISO 400 than ISO 200. Link to post Share on other sites More sharing options...
eriepa Posted August 20, 2023 Share #5 Posted August 20, 2023 2 hours ago, SrMi said: You got it right for ISOs. Real ISO is from ISO 100 to 6400. Looking at the DR graph (PDR vs. ISO), you will see only a gradual drop-off in the dynamic range. The dual conversion gain lowers the read noise at ISO 400 and raises the DR. Theoretically, you are better off shooting at ISO 400 than ISO 200. Thank-you, SrMi, really appreciate your taking the time to respond. I had thought that DR dropped off faster, but I see what you mean. Interesting point about ISO 400 too! Link to post Share on other sites More sharing options...
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