Arthur Woo
Well-known member
Hey Arthur, Les pretty much nailed it. When I said appropriate levels, check out the files to get an idea of what I mean. You will notice at each ISO level the Histogram is exposed almost identically. That would be proper light levels for the given ISO. Proper light levels at 4000ISO is still less light than at 2,000ISO for example. The a7s is designed specifically for clean low light images with its large megapixels and built in noise reduction. Those cams have a certain appeal because they apply gain to the image in camera to "boost" the amount of light gathered, and then apply aggressive noise reduction to counter the noise. A RAW cinema camera like a RED does not apply any in camera noise reduction and carries many more mega pixels which is not the greatest for high ISO. That is why the a7s and c300/500 are in the 12mp range, canon being 8mp I believe. Larger pixels = more sensitivity and less resolution to handle. This makes it not only cleaner (because more light is gathered per pixel) but the added in camera noise reduction further eliminates any noise there would have been there had the signal been captured RAW. If you want to try a test, shoot with the a7s in RAW stills mode and then do video at the same ISO levels right after. Is the RAW still just as clean as the video? No, there's plenty of samples online. A true RAW camera should not apply any noise reduction or sharpening and that is why the video from the a7s is cleaner than its RAW stills.
So again, it doesn't really matter whether you shoot at 2,000ISO or 4,000ISO on Weapon if you expose it properly for that ISO level. Like I said above, it's about getting a full histogram for the given ISO. That is the key to shooting RED. If you were to expose to the right without clipping, you will end up with an even cleaner image. Try it out and see for yourself, because when you do that, you are basically exposing for a lower ISO than you are actually shooting. Give it a try.
Thanks for all the replies everyone! Definitely helps clear up the confusion. When most people who shoot on non-raw cameras say "this camera is great because it can shoot xyz ISO", the logic is that of the camera applying gain and noise reduction in camera.
This goes against my experience shooting with those cameras (don't always shoot on my Epic, depends on the client request/budget), because usually for those shoots, there isn't enough light to begin with (usually low budget or doc style work where ample lighting isn't always an option). It also opens up a different way of thinking for me on shoots. I've been avoiding anything above 1280 ISO on LLO Dragon (again, since I am not used to thinking about higher ISOs being clean when ETTR). Will definitely try this out.