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

Started Mar 17, 2012 | Discussions thread
Andrew Westlake Senior Member • Posts: 2,928
No, no, no

Big Ga wrote:

Now, after reviewing the shots, you decide you might want to buy a new camera because you want better noise performance. You now need to review some identical side by side comparisons from different cameras, so really these need to be taken under the same conditions, which means the same source light intensity, the same aperture and the same shutter speed. Only then does side by side camera ISO comparison make real sense if you're trying to decide on which camera to buy based on its noise v ISO performance.

No, this is the whole point. You want examples that use the same exposure, as a function of light level, shutter speed and aperture. It doesn't matter what combination you use as long as the sensor gets the same amount of light.

Your extensive samples provide a range of test shots which show how what the output will look like when you set the camera to various settings such as different ISO and shutter speeds as calibrated by the manufacturer, however one then needs to cross reference these to DxO figures to be able to work out which of your test images need to be selected, if one is comparing images across camera models.

No, no, no. This is completely the wrong thing to do. You cannnot mix and match DxO's ISO numbers and our JPEG samples, you'll get entirely the wrong answer. DxOMark's ISO rating tells you nothing about the relative exposure we've used. We determine the correct exposure based on JPEG brightness, re-ratng cameras using DxOMark's ISO would result in JPEGs of different brightness.

What many people are asking for is a truly fixed set of parameters. Fixed lighting. Fixed aperture. Fixed shutter speed. The same for all models.

Then in these studio samples you'll get significantly different depth of field between sensor formats, so that would be a really poorly-designed test. People get sufficiently upset over tiny differences in focus as it is.

At the moment, it seems you can't look at an ISO6400 file from one camera, compare it with an ISO6400 image from a different model, and simply by looking at the test results, work out how the cameras are actually going to perform in real life when you have to take shutter speed into account.

No, this is the whole point I've been making. This is exactly what our samples allow you to do (but you do need to note our ISO test results for the cameras you're comparing).

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Andy Westlake
dpreview.com

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