- Posts: 105
- Joined: Fri May 03, 2013 7:58 pm
Hi Iverha
My advice is, if you're shooting raw, don't worry about ISO; in raw ISO is more of a display preview attribute than anything else; it doesn't seem* to influence the raw output in any meaningful way. When I shoot with the BMCs (in raw) I set Zebra for 100% and I just make sure nothing meaningful has zebra on it. This is effectively like shooting at 200 ISO... the results are amazing and the DR is out of this world (when you compress the dynamic range the output comes close to HDR).
The manual is a bit confusing because it says the optimum ISO is 800, but I think it says that because if the camera is set to 800 in raw it's a half-way point in the image level (between 200 and 1600) and as such will give you a better idea of what you're capturing.
More confusion originates from the analog gain in most cameras... it's my understanding that the native ISO on most Canon SLRs is 400... therefore 100 is like -6db gain. At negative gains there's a greater likelyhood that highlights in the image will overexpose on the sensor before they reach the Analog/Digital converters, and as such part of your DR is lost (ML ISO). It seems that the BMC doesn't have any analog gain (because the bit depth is large enough to capture the entire sensor's DR) and therefore the issue of ISO restricting DR on the BMC doesn't exist.
Once again, if I'm wrong, please correct me .
*seems because we don't know for sure (?) whether or not the camera applies analog gain based on ISO settings... but if it does it's negligible. The reason I don't know for sure whether or not ISO applies some gain is because zebra on the camera's display changes depending on whether you're on 200, 400/800 or 1600.