LINK TO ARTICLE ON IMAGE RESOURCE - DXO RATES GH1 ON A PAR WITH CANON 7D

Amin Sabet

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This certainly will be controversial, if it gets a lot of attention.

I personally put a lot of stock in the DxO results. As a RAW shooter, what they find with most cameras tends to agree well with my practical, real world findings in use of those cameras. However, their GH1 results make me wonder whether their findings may be skewed by manufacturer tampering with RAW data.

The G1 has the same sensor as the E-P1, E-P2, and GF1, and tests identically to those cameras in DxO analysis. As an owner of the GH1 and G1, my personal experience is that the GH1 image quality is, on the whole, better than that of the G1. However, I've always suspected that a good part of the difference is caused by Panasonic applying noise filtering at the level of the sensor, such that it is "baked into" the RAW. If my hunch is correct, then DxO is analyzing "cooked RAWs" from the GH1 and "raw RAWs" from the other :43: cameras.

Regardless of whether I am right about the above, DxO has several limitations. For example, the banding which is known to affect GH1 images does not factor into their analysis at all.
 

Brian Mosley

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Interesting, before the GH1 was released I was really looking forward to it... in expectation of a significant improvement in the sensor technology. The early samples showing clear banding at ISO 800 put me off.

Amin, I remember a lengthy discussion some time ago, started by Björn where the GH1 raw files were shown to be affected by NR settings... which suggests raw files are being processed.

I'll see if I can find the thread. OK, here it is.

Not sure what the outcome of that discussion was - I didn't see Ehrik's summary.

Cheers

Brian
 

Amin Sabet

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Brian, banding can be seen on GH1 files, but it mostly depends on exposure and processing. I don't usually see banding in ISO 800 files where I got the exposure correct, but I can see it even in an ISO 100 file if I have woefully underexposed and push the RAW file during processing.

As for the effect of camera settings on the RAW, the bottom line is that at ISO 800 and up, the higher you set the camera noise reduction, the less noise reduction is applied to the RAW. It's not very noticeable at ISO 800 but easy to see at 1600.

+2 NR is the least "cooked" setting for an ISO 1600 RAW, which is not only counterintuitive but also a pain in the neck if you want to shoot RAW + JPEG because the JPEG gets the most NR at that setting, while the RAW file gets the least.

Even taking into account the banding issue, though, I feel that the GH1 does give slightly better image quality than my G1 after processing RAWs from both cameras to the best of my ability. Also, Nik software's Dfine cleans up any banding quite effectively without significant adverse consequences to the rest of the image. It isn't cheap, but it does a great job.
 

Brian Mosley

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Well, the rumour is that Panasonic are about to release a new sensor - so hopefully we'll see another step improvement.

Cheers

Brian
 

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