Olympus OM-D (EM-5) comparison samples are now.. (continued)

Started Mar 17, 2012 | Discussions thread
Andrew Westlake Senior Member • Posts: 2,928
Re: Olympus OM-D (EM-5) comparison samples are now.. (continued)

Simon Cowell wrote:

Based on the answer above, how valid is it to present the comparison results in terms of the manufacturers's ISO settings when it is known that the ISO 12232:2006 standard allows the manufacturers to set the ISO values arbitrarily

That's something of a misapprehension. While the REI definition within ISO12232:2006 sort-of says that, our testing is essentially based on using the Standard Output Specification definition. That's what we report on, and that's how all of our tests are conducted. Most cameras conform to it pretty well in practice.

REI is actually a method of dealing with the vagaries of multi-pattern metering, but our testing doesn't rely on the camera's meter. It also lets manufacturers use context-sensitive tonality-adjustment processing for their JPEGs that can adjust the brightness after the event (called variously Auto Lighting Optimizer, Active D-Lighting, Dynamic Range Optimizer, Auto Gradation, iDynamic, etc.); needless to say we turn all of these features off.

and is applicable to sRGB output (not raw) only?

How does it make any sense to suggest a camera has a different ISO setting dependent upon whether you're shooting RAW or JPEG? The camera doesn't change its metering or anything when you change file format or color space.

Note, I'm not arguing here that what you do is invalid for a particular manufacturer/camera model, I'm arguing is not valid to compare/present noise results across camera models for a particular ISO value.

We test ISO, essentially according to the SOS method, and present the results in every review. All of our further tests are implicitly based upon that, because they're exposed so particular reference grey patches are rendered at a standard brightness. You do need to pay attention to those ISO test results when comparing cameras .
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Andy Westlake
dpreview.com

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