[libcamera-devel] softISP for libcamera

[Pavel Machek]

Hi!

> > > > That will result in shooting at 1/15, ISO50 -- resulting in blurry
> > > > photos (motion) -- even with sensors that could shoot at ISO500
> > > > without getting grainy. RPI pipeline has support for this, with config
> > > > file saying "stay at ISO50 to 1/60, then move iso up to ISO200 @ 1/60,
> > > > then start adjusting exposure again". It would be nice to reuse it.
> > > 
> > > 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).

1/125s, f/3.5, a.gain 1x does not correspond to anything, unless you
know camera details.

> > Anyway "minimal possible gain" is too simple solution for many cases.
> 
> That I don't dispute :-)

Ok.

> Also note that there's no reason for going lower than x1.0, even if the
> sensor supports lower values.

I'm not sure I agree here. x0.5 gain will still have a tiny bit lower
noise than x1.0, no? (Plus there's place for it if you have too much
light and can't make shorter exposure).

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