A few weeks back I did some comparisons using Rob Galbraith’s posts on various ISO settings to compare the quality of images of Canon’s 1D Mark IIII and the Nikon D3. Nikon’s claim is that the D3 handles high ISO’s better, even letting you set the ISO as high as 25,600 in-camera.
After looking at images for about 10 minutes I noticed the difference between the Canon and Nkon images at 6400. Nikon had more or less successfully eliminated the chrominance noise from its high ISO images. Canon’s images were full of the multi colored specs and as a result tended to deteriorate quicker at the higher ISO’s.
While playing with my camera last night I decided to try out the High ISO Noise Reduction option found in the custom functions settings. After examining the images and comparing them to the pre-noise reduction images it became apparent that the in-camera reduction made a huge difference.
Based on that I had to ask, if Canon allowed for in-camera 25,600 ISO, how would it look? While I couldn’t answer that question, I could certainly simulate it.
To simulate the extremely high 25,600 ISO I set the camera to 6400 (the highest allowed) and underexposed by two-stops. Then, using Photoshop, I adjusted the levels to make up the two-stop difference.
The first image is the Mark III properly exposed for an ISO of 50 (the lowest allowed). The second image is the 6400 underexposed and adjusted in Photoshop.