e-620 ISO 100 vs ISO 200 image & DR in-depth analysis

Started May 21, 2009 | Discussions thread
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Raist3d Forum Pro • Posts: 36,442
e-620 ISO 100 vs ISO 200 image & DR in-depth analysis

Disclaimer- this is a discussion about a technical aspect of the Olympus 620 (which most likely certainly applies to the E_30 also). There is no photography in the following posts, just a two snaps, but it may help to understand the tool you have with its capabilities a bit better (if you have the 620 or E-30), along with potentially dispelling some misconceptions.

If this sounds boring to you, not interesting, or you don't care either because you don't have the cameras or you just truly don't care, just skip this entire thread- this discussion is not aimed at you.

Those interested for whatever reason, carry on reading. And I encourage everyone inclined to do so to re-check/verify everything I am saying here. After all seeing things for yourself is far more important than what you read on an internet forum, plus it's always good to keep critical thinking skills.

So, as I had said in my extensive analysis before, I concluded that Olympus must have done something to the JPEG curve, moving it to capture more highlights at the expense of some shadows. At the end of it all it seemed rather obvious, but I wanted to recheck everything and verify that yes indeed both are identical and have the same dynamic range. Since after all I like to see things for myself and I have the technical know how, why not.

So, for this, I decided to tap on dcraw, which is the open source raw converter that many other raw converters use anyway, that Dave Coffin, what must be a programming genius has continuously updated, reverse engineering tons of camera raw formats. This is actually the base that LightZone uses for its RAW conversions.

The cool thing about dcraw is that you can't get much more RAW than this (unless you wrote your own raw converter). This has parameters and ways to get the data as close to the "metal" as possible. And the source code is open source so it can be verified, checked and rechecked and even modified (following proper licensing protocols).

So I embarked on another exploration and in the next posts the results.

My thanks to Dave Coffin for providing his code an expertise, and to Francisco J. Montilla for providing readily available updated binaries.

You can read more about dcraw here:


Warning: the following posts are image heavy and I used the PNG format to have lossless compression in all the images I am going to show. Also the shots are boring snaps. Not even 100 light years remotely close to a photograph.

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Raist3d (Photographer & Tools/Systems/Gui Games Developer)
Andreas Feininger (1906-1999) 'Photographers — idiots, of which there are
so many — say, “Oh, if only I had a Nikon or a Leica, I could make great
photographs.” That’s the dumbest thing I ever heard in my life. It’s
nothing but a matter of seeing, and thinking, and interest. That’s what
makes a good photograph.'

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