[libcamera-devel] softISP for libcamera

[Pavel Machek]

Hi!

> > > > > Let's please not refer to "ISO" in technical discussions. The ISO 12232
> > > > > standard is pretty much useless, "ISO" values are only meant for
> > > > > marketing.
> > > > 
> > > > Well, I believe "marketing ISO" is good enough to demonstrate my point
> > > > here :-). It is familiar "unit" to people doing photography. What
> > > > would you suggest as replacement?
> > > 
> > > Just analog gain. There's nothing anywhere that maps a x1.0 analog gain
> > > to ISO 50, 100, 200 or any other value.
> > 
> > Exactly, and that means that ISO still has its place, right?
> > 
> > 1/125s, ISO100, f/3.5 corresponds to known lightning conditions across
> > range of cameras (including film ones).
> 
> ISO 100, as a sensitivity value for digital cameras, doesn't mean
> anything. It's an arbitrary value picked by the manufacturer. For film
> cameras it could be used to compare sensitivity of films, for digital
> cameras, it's meaningless.

I don't believe so. It has same meaning as for film cameras.

If I want to take a photo of my horse on cloudy day, I'll use 1/125s,
f/3.5 on a film camera with ISO100 film inserted. And when that gets
right-exposed picture, any digital camera with 1/125s, ISO100, f/3.5
setting is expected to produce good picture, too.

It may not map easily to gain, but it is fairly useful parameter for
photographer.

Best regards,
								Pavel
-- 
People of Russia, stop Putin before his war on Ukraine escalates.
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