[Digikam-devel] [Bug 188573] RW2 converter broken for low light images

[Alex Tutubalin]

https://bugs.kde.org/show_bug.cgi?id=188573





--- Comment #17 from Alex Tutubalin <lexa lexa ru>  2009-04-02 14:09:12 ---
First. You *need* to autoscale because RAW data is limited to some non-round
value (i.e. 14735 for most ISO on Canon 5D mkII) and full-scale is 16 bit
(0-65535).

Second. Autoscaling in linear space (before gamma conversion) works very well
for *all* images (due to linear nature of RAW image). Autoscaling is virtually
lossless (we need to round to nearest integer, but in 16 bit rounding effect is
very tiny).

The only question is autoscaling size detector. If you will use real maximum
value from RAW, autoscaling will be affected by hot pixels. If you ignore too
many bright pixels, you'll have too scaled shadows (as in your eclipse shot).

May be, that 1% for highlights (clipped pixels) is too optimistic. It works
well enough for most pictures, but photographers use different styles of
exposure (exposure by meter, ETTR and so), so different setting for automatic
scaling may be useful.

I'll think about adding some autoscaling control in LibRaw postprocessing
routines.

-- 
Configure bugmail: https://bugs.kde.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.