ISO 'Sweet spot' for sensor on 7D and 5D

[eco_bach]

Hi
read somewhere that 800 was the 'sweet spot' for the MX sensor on the RED camera.
Anyone know what the 'sweet spot' would be for the 7D, 5D?

I'm guessing sweet spot refers to the balance between optimal dynamic range, least noise, and highest sensitivity?


200, 360, 400?? or

 

[steventimothy]

Since it's not raw, there isn't really one. Basically, the lower the ISO setting, the less the noise. If you could shoot everything at 200, the picture would look the best.

 

[Angry Leprechaun]

Steven's right, but the Canons can handle noise very well. I usually shoot at around ISO 400 but if lighting isn't the most controlled I can get away with ISO 800.

On Zacuto.com watch the Great Camera Shootout. There's a great section in there where they cover ISO speeds.

 

[Exact]

I've read the comments on the web from lots of DPs, but then did my own tests. What I found on ALL my cameras is that the 160/320/640/1250 produce the best results in terms of low noise. 640 is my preferred ceiling for the crop sensors but I do shoot them at 1250 when light it low. A little kiss from Neat Video noise reduction works wonders. I don't hesitate to shoot at 1250 on the 5D, with 1600, 2000 and 2500 all working well with a little noise reduction.

The higher the ISO, the lower the dynamic range. In terms of 'sweet spot', there isn't one of any obvious significance. Shoot at the lowest ISO you can (see the settings above) for best results.

 

[yrpfilms]

I've read the comments on the web from lots of DPs, but then did my own tests. What I found on ALL my cameras is that the 160/320/640/1250 produce the best results in terms of low noise. 640 is my preferred ceiling for the crop sensors but I do shoot them at 1250 when light it low. A little kiss from Neat Video noise reduction works wonders. I don't hesitate to shoot at 1250 on the 5D, with 1600, 2000 and 2500 all working well with a little noise reduction.

The higher the ISO, the lower the dynamic range. In terms of 'sweet spot', there isn't one of any obvious significance. Shoot at the lowest ISO you can (see the settings above) for best results.

I heard that outside of the traditional range ie 160/320/640/1250 the camera artificially boosts the gain.

 

[Samuel H]

I heard that outside of the traditional range ie 160/320/640/1250 the camera artificially boosts the gain.

and I think 160/320/640/1250 are pulled down from 200/400/800/1600, and the reason people say they get less noise is that they boost their lights or aperture

but Canon has never spoken in this respect, so nobody really knows

I did some tests (terribly non-conclusive, but informative) and found hints that it is the amount of light that reaches your sensor (lights, filters, exposure) and desired final image (how much you push or pull) that primarily determine how much noise you get:
* light for ISO 400, shoot ISO 320 and then push, and you get just a little bit more noise than you'd get if you had shot ISO 400 (and it is only because you're torturing your footage in post)
* light for ISO 320, shoot ISO 400 and then pull, and you get just a little bit more noise than you'd get if you had shot ISO 320 (and it is only because you're torturing your footage in post)

http://www.vimeo.com/20486388

but some people have measured higher dynamic range with ISO 100x than with ISO 160x, that's why I think 160x are the derived ones

 

[Exact]

and I think 160/320/640/1250 are pulled down from 200/400/800/1600, and the reason people say they get less noise is that they boost their lights or aperture

We rarely use lights, so that's certainly not the reason

It's true that 320 is pulled down from 400 and 640 is puled down from 800 and you do get less noise. If I need to shoot at (say) greater than ISO 200, then I tend to shoot at 320 and 640 rather than 400 or 800 because there is less noise.

Shooting at 320 (deliberately under exposing) then pushing in post is not the way to do this. If you need 400 then use 400, not 320 then push in post. Always get your exposure right in camera and it's always going to be better in post. Use noise reduction where needed.