Heh, i'm at whatever iso i need to be.
I do remembering hearing that something like iso100 is okay, iso160 is better, but iso130 is worse then iso200. or something.
God i can't remember, but bottom line is i really don't bother caring, i normally go by 160,320, 640 just out of habit and because i like those numbers better, randomly.
Rob: I don't shoot iso50 too often so i cant comment on whether or not it has any issues, but its a 5dmk2 thing to band at iso100, the 5d1 and most other canon cameras i've used have not experienced this. However, the 5d1 did experience banding when coupled with a cactusv4, which leads me to believe it is a defect in the sensor RF shielding that is causing the banding which is why it would present itself even at iso100. Most don't mind it as its not as present and obvious as some would suggest, in my opinion oldgen AF and the banding is the price to pay for such a ridiculous MP FF sensor with highisos so cheaply, considering that when it came out 20MP was what, 1ds3/D3 territory period. The 7d was canon's late answer to the D700/D300 was which the answer to the 5D1, Nikon now has to answer the 5d2, but since canon had that mangled AF, Nikon hasn't been in a hurry and is instead trying to kill both the 5d2 and 5d3 in one shot with the d800. (At least thats my reasoning, and you heard it here first folks, though you probably already knew, and can you tell how jacked up i am on caffeine yet? couple more to go, then a shopping trip, then i can be laid to rest.)
I don't have a cat, i can't feed it, stop trying to get me to buy a cat POTN! I WONT DO IT! But i will experience a passive +3 increase in productivity.