Reply To: S2 ISO adjustments. What does it all mean

allegretto;1235 wrote: OK, this is what I mean;

http://sensorgen.info/LeicaM9.html

wish I could upload it to make it easy but it seems that this site wont take reasonably sized attachments… or maybe I’m screwing it up. In any case;

you can see that raising the ISO of an M9 compresses DR and does NOT decrease read noise. That it is a CCD is not the issue, read noise is. Further, as ISO increases, saturation decreases (makes sense of course)

the implication here is that the M9 is also an ISO-less camera. Increasing ISO is actually deleterious to image quality from compression. One is better off nailing ISO at 160 and shoot using the stop or speed one needs for a given shot. Or, if it doesn’t matter, just ETTR as much as you dare. The resultant underexposure, if present, can be upped in PP.

I just wonder how the S2 works… no data yet.

Not sure if this translates to real world results. An easy test would be to shoot a test target at ISO 160, underexposed 3 stops and at ISO 1250 properly exposed. Boost the ISO 160 shot 3 stops in LR and then compare. Without doing the test (yet) my guess is that the 1250 shot will look better. If I get a few free minutes today, I will do the test with an M9 and an S2.