on July 27, 2014

Going Native: Are you shooting at the wrong ISO?

A lot had been written about native ISO, and analog ISO vs digitally “pushed” ISO.

Let’s start off with the basics.

ISO is how sensitive your sensor is to light. The higher the ISO, the brighter the image is. Because if this sensitivity, it also introduces unwanted artifacts- called noise, into the picture. This produces a very digitally corrupt look that can be lessened to some extent in post with a noise remover, but it is always best to get it right in camera when possible. For this reason, you want to keep your ISO as low as you can get away with, and if you have to go above 1250, you would be far better off with either a faster lens, or an additional light source.
The folks at Canon give us ISO in increments of 100. Zacuto told us in their great Zacuto Shoot-out that the native ISO of Canon’s come in increments of 160.
In the latest nightly release, we see that the analog exposure for Canon ISO is indeed in increments of 100, but that the sensor pulls a cleaner image in increments of 160 because it is actually digitally PULLED from the ISO of 200 with a 1/3 stop of light lost. (There has also been speculation that this will cause some loss of dynamic range, but I have yet to witness it.)
What this means:
Shooting at ISO in increments of 160 will give you a cleaner image with less noise. The option to see the difference yourself is the proof in the pudding.
While this may not be the technical “native ISO” the effect is the same. You have control over the sensitivity if your sensor to produce the cleanest images possible.
So what does this mean for you? Try to keep tour ISO low to reduce noise, but as you get into higher ISO ranges, thinking in multiples of 160 will save you from unwanted noise. When you star shooting over 1250, you should really think about either adding more light or getting faster glass.

Here’s a great image posting over at the Marvels wordpress:  They make a great picture profile and their study of the work is amazing.

http://marvelsfilm.wordpress.com/2009/10/10/canon-7d-noise-and-iso-test/