High ISO noise comparision (1D)
IntroductionThere are many comparisions of high ISO noise floating around the web. The problem with many of them is that they're comparing apples to oranges because tonal rendering differences (TRC's and/or settings) aren't taken into account. A conversion that compresses shadows will also compress and darken any noise making it less visible. This study is an attempt to compare high ISO Canon 1D image conversion via three raw converters: PhaseOne's CaptureOne DSLR (C1), Adobe's Camera Raw (CR), and Canon's Raw Image Converter as employed by YarqPlus (YP).
MethodologySince I rarely take high ISO photos, David Pennybaker kindly provided an example. My goal here was not only to match tonality, but to make simple adjustments that gave an image that reflected a realistic goal rather than some artificial adjustment just to illustrate possible noise issues.
White BalanceThe C1 and CR conversions were click balanced on the lower left corner of the sign at the top of the image. No attempt was made to conceal or correct for the colored stage lights. I tried a number of white balance options, including presets, and in my opinion this choice gives a reasonable rendition of the image. Since YP has no WB click facility I set it to Kelvin:2800 which seemed a fairly close match to the other conversions, but note that this is a bit cooler (or 'bluer') than click-balance results in C1 and CR.
Tonality AdjustmentsMatching tonality between output of various converters is no easy trick and my attempt is but a close approximation. I paid particular attention to matching the shadow areas. The basic procedure was as follows:
- I converted with C1 making a 1/4 stop reduction in EC. It has been widely observed that C1 renders 1/4 stop to 1/2 stop brighter than other converters and this adjustment seemed to make a closer match with the others.
- I converted with CR tweaking the tonality sliders in an attempt to match the tonality of the C1 conversion.
- YP was converted using default settings since tonality adjustment (other than EC) is not possible.
- A curve was constructed in PS to match the tonality of the YP conversion close to the tonality of the C1 and CR conversions which naturally expand more shadow. The curve is shown on the Settings page.
I spent quite a bit of time attempting to match tonality and obviously did not attain a perfect match, particularly in the midrange where the C1 has lower contrast. I paid particular attention to matching the shadow areas where the 100% crops were taken.
ConclusionsI think the main conclusion to be drawn is that the noise handling of the various converters is a lot closer than most comparisions show. In my opinion the C1 conversions have an edge, but the differences aren't dramatic. My other observation is that adjusting the noise options in the various converters, while helpful, did not produce dramatic improvements. Also, I wouldn't attribute too much significance to the color differences in the noise. These may be attributible to WB differences. For instance, YP's WB was bluer than C1 or CR out of necessity.
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