Canon T3 High ISO RAW

Canon T3 High ISO RAW Image Quality

We often convert our Still Life RAW files with dcraw, an excellent freeware raw converter. dcraw usually offers timely support for the latest cameras, but more importantly, it does not apply any noise-reduction, sharpening or other corrections such as geometric distortion correction to the output files. (We found that some other RAW converters still apply limited noise-reduction when their NR settings are set to zero, and they often also apply other corrections depending on the make and model of the camera). There will always be differences between RAW converters, in terms of the sort of demosaicing algorithms they use (the processes by which they convert the separate Red, Green, and Blue data sets to an array of full-color RGB pixels), but dcraw seems to use a fairly generic algorithm that delivers good sharpness with relatively few artifacts, and can be counted on to not apply any noise reduction if you don't want it to.

Below are crops from Canon T3 high ISO RAW files compared to RAW files from other entry-level SLRs from Nikon, Pentax, and Sony.

Here, we can that the 12-megapixel Canon T3 closely matched the 14-megapixel Nikon D3100's noise performance, though the Nikon showed less noise in the red leaf fabric. The 12-megapixel Pentax K-r produced the cleanest RAW files of the group, but as you can see by the blurring at ISO 3,200 and above, the K-r applies noise reduction at high ISOs which is something we'd rather not see in RAW files. (When working from RAW files, users typically will want all available information in a image, which is why perceptual noise reduction applied to RAW files is generally frowned upon.) The 14-megapixel Sony A560 produced RAW files with the most noise in this group. The story is similar with the Sony A290 and A390 (not shown), which use an older CCD sensor design versus the A560's CMOS sensor. They produced even higher levels of noise.