Originally posted by dosdan Originally posted by dosdan Hi Dan,
interesting contribution to the discussion. Thanks!
The D7000 figures and K-5 figures and remaining uncertainties however are such that the conclusion (D7000 fixed at analog gain around ISO 100) is likely but not failsafe. It is all based on a single electron read-out noise difference.
I prefer a point of view where all of this doesn't matter and it all boild down to one statement:
The K-5/D7000 only add 2-3 electrons noise to the signal whatever be the ISO setting (where a fully saturated signal is around 40000 electrons).
Originally posted by simico I can't really see a practical benefit for the photographer. I don't really get the "preserve highlights" thing either - meter and set exposure carefully, then you won't have blown highlights regardless of ISO.
I tried to explain the practical benefit for me as a photographer in a couple posts above.
With my K-5, when I see that the scene contrast is high, I dial in -1, -2 or even -3 EV exposure compensation without hesitation. I check that the ISO wasn't upped (it shouldn't because underexposure of course allows for lower ISO in an Auto ISO setup). Even fill flash against the sun isn't mandatory anymore. Just keep the ISO down.
Then, in LR (Raw now is a must), I use exposure, levels and eventually fill light (don't forget to set blacks to zero first) to recover what I would have seen at a higher ISO step -- but without the blown highlights.
This is NOT true: "meter and set exposure carefully, then you won't have blown highlights regardless of ISO". Except if you allow for EV compensation to avoid blown highlights. But then, you already use the sensor in an ISOless style (w/o realizing obviously): if you use -EV compensation then you lower ISO (in Auto ISO or you do so manually if you care about all three settings).
In lesser cameras (than the K-5), when using -EV compensation you had to care about resulting shadow noise (because EV-boosted shadow noise was higher than the normal noise you would have obtained at a higher ISO setting). Not anymore with the K-5.
You may call it ISOless like the thread title says.
I prefer to call it increased dynamic range and increased photographic freedom.