Canon 1Ds Mark III Noise and ISO
Canon 1Ds Mark III Noise and ISO settings
Why I turned off all those extra ISO settings…
The other day I noticed a post on the FM forum, pointing out that ISO settings for the 1Ds2 and 5D are not all that they may first seem…
‘The full stop ISOs ( ISO 100, 200, 400 and 800 ) are implemented with hardware gain settings (in the sensor). But the ones in-between and 50/1600/3200 are implemented through software. The full stop ISO has lower noise than the in-between ones.’
I decided to do a quick test with the 1Ds3…
My suspicion is that this test might show similar results for many DSLRs (not just Canon)
I noted similar results for the Canon 7D
I’ve also written a page with comparisons between my 1Ds and 1Ds3, along with my thoughts and impressions about using the 1Ds Mark
Please do let me know if you try this with other cameras? I’ve seen examples suggsting that the 1D3 does not exhibit the same behaviour
A series of shots were taken with incremental ISO settings:
The camera was set to manual, with a lens cap on and the viewfinder shutter closed. I’m just looking at dark noise here, so any image contant would not be of any use.
Raw images were taken and processed in ACR with no noise reduction and black level set to zero (to show up noise)
An additional set of images was processed at +4 exposure compensation to really show up any noise.
ACR Settings – all default unless shown
The histogram gives an idea of the dark noise levels at each ISO setting – the drop in noise from 160 to 200 is quite noticeable even at the low levels found in this camera.
The next set of shots have had the exposure racked up 4 stops in ACR to show more details of noise
I’ve included a 100% crop so you can get an idea of what it’s actually like when you push images this far
ISO 50 (exposure at +4 stops)
Remember that ISO 50 on the 1Ds3 is an optional setting, since although you have even lower noise in the shadows, you lose dynamic range (at the top end) See the information about L(50) and H(3200) ISO settings in the manual
ISO 100 (exposure at +4 stops)
ISO 125 (exposure at +4 stops)
ISO 160 (exposure at +4 stops)
ISO 200 (exposure at +4 stops)
ISO 250 (exposure at +4 stops)
ISO 320 (exposure at +4 stops)
ISO 400 (exposure at +4 stops)
ISO 500 (exposure at +4 stops)
ISO 640 (exposure at +4 stops)
ISO 800 (exposure at +4 stops)
ISO 1000 (exposure at +4 stops)
ISO 1250 (exposure at +4 stops)
ISO 1600 (exposure at +4 stops)
For normal usage, the default ACR Black level setting of 5 and default colour noise reduction in ACR makes it very difficult to see much image noise in ‘real world’ photos at ISO 1600
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