The prices on the Sigma DP2 Merrill compact, fixed lens cameras dropped a bit ($800 in the US) and I decided to finally see for myself what all this "Foveon" is about. Naturally, since I also have a very good K-5 and stable of excellent lenses, there is going to be some comparison.
First things first; the Sigma DP2 Merrill has the "latest generation" of Foveon sensor (a 15.4 MP APS-C sized chip that captures all colors of light at each photosite -
read more here) and a 30mm f/2.8 fixed lens with an internal leaf shutter. We all know the K-5, and to find a close approximate comparison, I used the FA 31mm f/1.8 Limited lens on it. Pretty much the best Pentax "normal" against what many claim is the best compact "normal" lens, leaving the fight up to the sensors.
I'm going to focus on the image performance in the sole areas where the Sigma is capable, which is well-lit landscapes and static tableaus. The Foveon cannot handle ISOs over 800, and the compact lens AF cannot handle moving targets, but frankly I try to keep my K-5 at ISO 80-200 for these types of images anyhow.
While I've shot numerous images with the Sigma and the K-5, my findings are best summarized in a single (and therefore dangerous) image. This is when both are focused at a medium distance under overcast light (actually light snow) on the same ISO and aperture, letting their meters figure out the shutter speed. The claims of the Foveon are that it performs like a "46 Megapixel" sensor, but most reviewers peg it at somewhere near 30 MP, and I truly only see this kind of detail at 100% pixel-peeping level.
So, here is a side-by-side where the two images have been somewhat color balanced, but
no sharpening has been done to either image (which is not my standard way of doing things).
The Sigma is on the right (click for full-res):
Now, just to temper everybody's reaction, I will be posting many more comparison photos at all zoom levels, and then providing a link to the full-res files for download and perusal.
Also, it should be noted that the Sigma raw files can only be processed in their (slow) software, so I saved them as 16-bit neutral tiffs and opened them up in ACR to try to balance their color to the PEFs. Pentax simply destroys all APS-C comers when it comes to color fidelity and dynamic range (IMHO) with the K-5, and the Sigma is no different. The main reason to compare these is because of the
supposed increased sharpness and detail of the Foveon files. At first glance it looks like that's quite clear...
More to come!
Last edited by panoguy; 04-06-2013 at 07:32 AM.