On the dynamic range of RAW...

Started Nov 30, 2004 | Discussions thread
Bill Robinson Veteran Member • Posts: 4,462
thank you for the link .nt

Brian G. wrote:
Hi Anders,

echelon2004 wrote:

Please note that all the pics we see are 8bit jpeg's.
It is possible to get the same result's by spot meter the brightest
and darkest points and then calculate the exposure from both these
points.

Well, you won't get exactly the same results doing that. I am a
huge fan of spotmetering, but when you meter your lightest and
darkest points and get an exposure based on those, you are getting
an average exposure. If you are shooting in jpg, you will still
lose the darkest blacks and lightest whites as your images is
converted to jpg in-camera. Even Olympus' multi-spot metering is
just a weighted average calculation based on the areas you've
metered for it. You will still have more dynamic range shooting
the scene in RAW. In the example I posted above, that image was
processed within a range of 8EV. No jpg will give you that- the
info just isn't there in an 8-bit file. Remember- a 12-bit RAW
files contains 4,096 discrete tonal levels. An 8-bit jpg contains
256. Tonalities are always lost during the conversion to jpg. If
your exposure was good to begin with, and within the limts of the
camera's sensor, then it doesn't matter too much- 8-bit will be
fine. But if you need to really start adjusting, jpgs simply
cannot compete.

I found a good article for anyone who would like more info:
http://www.normankoren.com/digital_tonality.html

This is a great site, incidentally, and there is much useful info
there.

If reducing the contrast in cam the result should be about the
same, naturally without the controll and predictability=)

If shooting in jpg, I would defintely reduce contrast to capture as
much detail as you can without blowing highlights. In fact, when I
shoot jpgs, I always have contrast turned down as far as it will go
(-5 on my 8080). But even here, you'd be better off shooting in RAW
instead as far as dynamic range goes.

I allways shoot raw though so don't really know why I'm making this
post

Nice pics!

Well thank you.

Kind Regards,
Brian

Anders

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cheers
Bill

Gotta believe in something....believe I'll take another photo!

http://www.potd.com.au/billrobinson/
http://bill6764.fotopic.net/

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