ISO stuff

[topcatproduction]

Just saw on another thread that the D90 ISO starts at 200 instead of the usual (or at least in the Canon world!) 100, is it because the IQ on 200 is now as good as 100 so it is simply not needed?! Still being an amateur I have basically understood to just use as low an ISO as poss to get the best IQ- hence being slightly confused by the lack of 100 on the Nikon! Can someone put me out of my misery?

On a different strand can we assume that in a few years time ISO technology will be so good the majority of people won't bother changing it from say 3200 or something?!

 

[lawrenceots]

I believe it is because the base sensitivity on them is 200,similar to the older Pentax. If you then 'pull' down to 100 on the D90, I believe that increases noise! I've got so used to 200 on my Nikons' tried using 100 on a 450D and it was just too slow!

 

[Canon Bob]

.... Can someone put me out of my misery?

I'll try

Two items highlighted in marketing are Noise and Dynamic Range and Canon and Nikon push these features to varying degrees. Attemping to increase the dynamic range will introduce noise and it then becomes a trade off as to where the line is drawn. Nikon sacrifice a little more of their potential DR in order to make their noise figures look a little better....Canon like to show off their dynamic range despite the fact that there's a little more noise involved. Dropping the Iso down to 100 will knock a little off the DR (probably 1/3 stop or so). Canon's DR figures are generally good enough that 1/3 stop loss is acceptable to the marketing guru's. Nikon, on the other hand, have already traded off a little DR for the improved noise signature so don't actaully fancy losing anymore for something that is only really beneficial if you want to make exposure times longer.

Bob