Test results for Canon SLR video ISO settings on Vimeo

by adamhanlon Friday, May 6th, 2011

Andrew Schär has published results of tests he has conducted using a Canon 60D in video mode at various ISO settings. It has been rumoured for some time, that Canon SLRs have a “sweet” ISO if the setting is 160 or a multiple thereof. The tests show that the best ISO’s to use for video, starting from lowest noise level to highest are as follows: 160, 320, 640, 100, 200, 400, 800, 1250, 125, 250, 500, 1000, 1600, 2500, 2000, 3200, 4000, 5000, 6400.

Interestingly, Andrew has found that 160 is also the best setting for still photography.

Testing Canon’s ISO noise in Video mode on the 60D from Andrew Schär on Vimeo.

Whoa, I just read my last post and I think I have been out of the water too long. The concept I wrote about is correct, but a 12 bit capture only has a total of 2048 levels of tonality in the last level of EV before clipping, not 2048k levels. The total capture of a 12 bit image is 4096 levels of brightness or tonalities. One half, or 2048 levels, are found in the +2 to +3 EV range, which reinforces my claim that overexposing images will give cleaner images. However, I would only overexpose by +1EV like Shawn suggests. Also, my per channel comments were wrong, levels of tonality are total and not per channel. Color values are per channel. Good thing I am diving today. Geeze... Thanks to all that saw my mistake and did not flame me! Barry
Posted by Dupsbear on 2011-05-10 09:26:01 Spot on and exactly what I read as well. Real life experience has also shown me that when pulling up underexposed images I don't get near the same tonal range. Better to over expose by +1 shooting raw. Underwater the clipping part is really tough when sun or strobe is involved. -Shawn
Posted by Shawn Heinrichs on 2011-05-09 15:07:14 Shawn, you are so right about adding noise in post! Noise is also added in capture by underexposing images. An image underexposed by 2EV only captures 128K tonalities per channel; over +2EV and right below the +3EV threshold, 2048K tonalities per channel are captured. Our camera's processor makes up for the missing (2048k per channel VS. 128k per channel) information when underexposing by adding noise.Missing is a really incorrect usage of the word, a sensor captures the same amount of information in each file, but if there is no information noise is the result. So, for the cleanest images, over expose, but not to the point of clipping, then tone down the images in post. One should research my comments above as there is not enough room here to completely explain. Barry
Posted by Dupsbear on 2011-05-09 11:17:01 This is great. I have spent hours and hours scouring various sites like Phil Bloom and doing my own testing on this issue. Great to have it resolved in one place. Basically the "non'native' ISOs are digital shifts from the natives that produce their own noise. But keep in mind in post your make adjustments that can also produce noise. There are some very interesting discussions online about this native ISO topic that complicate matters even more! -shawn
Posted by Shawn Heinrichs on 2011-05-09 01:48:45 Mine T2i does multiples of 100. It would be interesting to see this test with that camera sometime.
Posted by focker on 2011-05-08 23:52:37 Hi Focker, My D300s does not have ISO 160 either. Notice that I wrote that ISO 320 gave cleaner results than ISO 200. The whole idea of the article is that MULTIPLES of 160 are cleaner, not just ISO 160. I realize this concept is hard to grasp from what we always understood when using film. With film, the lower the ISO, the cleaner the image. Apparently, this is not the case with digital, or at least with our few tests. Barry
Posted by Dupsbear on 2011-05-08 13:26:45 I have 550D (T2i) and apparently there is no option to do the 160 ISO, do you suppose a ISO200 would be the best choice on that camera?
Posted by focker on 2011-05-08 12:12:52 In my last post, I kept saying sharper images. What I meant was cleaner images. However, the cleaner images do look sharper. Sorry if my post was confusing. Barry
Posted by Dupsbear on 2011-05-08 11:57:57 Hi Adam, Marty Snyderman and I just performed a similar test using my Nikon D300s, to research what Marty learned from Seth Resnik of D65 workshops. For those that do not know, ISO 200 is the lowest numbered ISO on my camera, although the ISO can be changed 1EV by forcing the ISO to a lower setting that is not numbered. In our tests, we shot medium focal length shots of Marty holding a white post-it note with the camera settings written on the note. Screen grabs of each video confirmed that ISO 320 was sharper than ISO 200, the "base" ISO of my camera. Additionaly, ISO 640 was sharper than ISO 400 and very close to ISO 320. Good job, and thank you Andrew, for doing such a complete test. Thanks Adam for posting this article and reconfirming our test results. Barry Guimbellot
Posted by Dupsbear on 2011-05-08 11:55:27