What is "best practice" for using RawDigger with MagicLantern's Dual-ISO?


Do you have one or more Canon DSLR's and installed the MagicLantern (ML) firmware? If so, have you used the Dual-ISO capability that merges different ISO's together for greater dynamic range? (my impression is there is a cost of some resolution for this).

I've taken series of images with a progression of shutter speeds, like ML's enhanced Auto-Bracket with 12 steps of 0.5 EV to start from under-exposed, and going past over-exposed. Then I've looked at the files with RawDigger.

I may be doing something wrong, but the results with Dual_ISO don't seem as consistent and understandable as with single ISO. It seems difficult to blow the highlights, at least according to RD values.

With single ISO, there seems to be a fixed value that is very close to the same for each RGBG channel that indicates "blown channel", like 14,737 with my Canon 5d2. With Dual-ISO, this values seems to "float".

Should the Dual-ISO files be in a separate directory than the single-ISO files? It seems like RD has some "memory" of what the previous file was, in terms of what it considers over-exposed. Do I have a setting wrong?

I have not used Dual ISO

I have not used Dual ISO (when it  arrives in ML firmware, it works only with several cameras), but I've see some samples.

AFAIK, DualISO changes amplification for odd/even rows (or columns, cannot remember), so one row uses ISO 100, while another ISO 1600. Sure, the peaks, average, noise will look strange in this case, because RawDigger does not do any correction for RAW data (e.g. dividing ISO1600 values to 16 to match ISO100 pixels(

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