Foveon sensor here I come!


What’s this? Another new camera?

Yes. It’s a Sigma DP1 Merrill.

Box-like sums up the styling.

(Sitting on top, in attractive but poorly matched silver, is a Voigtlander Brightline 28mm optical viewfinder.)

The Sigma DP Merrills are not particularly good cameras but they contain a very special and unusual APS-C size sensor and create images of stunning resolution and quality.They come in three fixed lens options: the 28mm equivalent DP1M, 45mm equivalent DP2M and 75mm equivalent DP3M.

I’ve been wanting to pick one up for a very long time but it was only when the price recently dropped significantly (due to the upcoming Sigma DP Quattro) that I felt able to do so. After selling a very fine set of Takumar lenses which I hardly ever used, in order to finance it, I now have a DP1M in my possession. It was a close call whether to get the DP1M or DP2M but in the end I decided that 28mm was the more useful focal length, even though the lens on the DP1M is not quite as good as that on the DP2M.

If you’re even slightly interested in digital photography you most probably already know about the Foveon sensor. Most digital cameras use Bayer sensors which are effectively colour-blind. In order to detect colour information a regular array of colour filters is put in front of the sensor; 50% of these filters are green and 25% are red and blue respectively. The end result is that colour resolution is much lower than the number of photosites (pixels to you and me) on the sensor and a complex “demosaicing” algorithm is required to interpolate (guess) the various colour values at each photosite. Worse, because the colour filter array can cause jagged artifacts in certain situations, another filter (an “Anti Aliasing” filter) is put in front of the whole set-up to very sightly blur the image. This of course lowers the resolution even further. The Foveon sensor works differently; it is made of three light-sensitive layers.The result is that each photosite detects actual RGB colour information. No interpolation is required. The Anti-Aliasing filter is also unnecessary and is not present. Foveon sensors thus have very high resolution and a different look to most other sensors. They also make the most beautiful black and white images with gorgeous transitions between tones.

Unfortunately Sigma have so far put this wonderful piece of technology into a rather underwhelming set of cameras. Battery life is the worst issue and is truly laughable. I got just fifty shots today before the battery died. It’s no accident that Sigma provides two batteries with the camera, but it’s not unheard of for Sigma Merrill users to cary six of them for a day’s shooting! They are also rather slow – even with a 95m/sec SD card they can take ten seconds to write a raw file. Focusing, though acceptable, is on the slow side too. To be honest this is largely irrelevant because the Merrills are simply not for action shooting and street shooting will be challenging.

The other major issue is intrinsic to the Foveon sensor itself. Because of the layered nature of the device noise very quickly becomes a problem and for colour work it’s inadvisable to shoot at anything over ISO 400 and ideally ISO 200. The Sigma Merrills are really base ISO cameras.


Finally there is the fact that the raw files can only be suitably converted via Sigma’s own Photo Pro software which could win awards for slowness and clunkiness.

These numerous limitations really become insignificant however if you treat the Merrills more like modern equivalents of the old large-format view camera. the Merrills are cameras to take time over, to use for more considered shooting, to shoot on a tripod. If you treat them this way the Merrills will reward you with the most amazing image quality. They are pretty much universally praised for the photographs that they produce.

As Jonathan Valin said on his blog The Absolute Sound: “Trust me on this: If you are willing to live with the many, many limitations of the Merrills (particularly when it comes to ISO, battery life, and post-processing), you will not find a higher resolution, truer-to-life camera this side of a medium-format rig with a LEAF Credo 80 back and Schneider/Rodenstock lenses. Even the $3300 (without lens) Nikon 800 E does not exceed the Sigma in resolution, micro-contrast, and, IMO, color. For shooting stationary (or relatively stationary) subjects in good light (i,e., at ISO 100 to 200), the Sigmas are simply unbeatable for the money. For shooting moving subjects or shooting in low light, virtually any camera in the world is a far better choice.”

What am I going to do with the Merrill? I really have no idea! Certainly I do sometimes shoot landscapes or cityscapes that would benefit from such stunning image quality… but it remains to be seen what, if anything, the DP1M brings to my photography. Stay tuned…


2 thoughts on “Foveon sensor here I come!

  1. I have experimented with the Sigma SD1 Merrill. Same sensor as the DP series, but with interchangeable lenses. I too like the “look” of the images from the Foveon-Merrill sensor, but I cannot figure out why. I have compared resolution with my 16.7Mp Canon 1-Ds i, and whatever fans of the Foveon might say, and whatever theory might appear to predict I see no greater resolution and only marginally greater sharpness (acutance). It is not the colours either. In fact out-of-the-camera the colours often have a sickening yellow/green cast, and sometimes brown/green/magenta blotches, and they take a lot of work in post-processing to get anything that is at all realistic and/or pleasing.

    Nevertheless, a disproportionate number of my very best images have been made with the SD1, even with an inferior lens (the17-70 f/2.8-4 … which is best used as a 24-55@f/5.6) … and that is despite all the SD1’s operational deficiencies (high-ISO noise, slow write to card, slow AF, inaccurate metering, and miserable battery life)!

    For a while I thought, as some web sites have suggested, that it was because all colours were equally sharp and detailed, but comparing careful with results from my Canons squashes that idea too.

    So if anyone can explain what it really is that makes Foveon images look so special, please tell.

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