Some reviewers said the Sigma DP2M (and DP1M, DP3M) 16Mpix APS-C Foveon sensor resolving power is on par to the 40-50Mpix medium format cameras like Hassled.
When i first saw full size images of Sigma DP2M, I’m just shocked. I have never seen anything like this detaility, particularly in such an ugly box design when i bought it at just around $650. (cheaper than a decent lens) Its APS-C foveon sensor, just 16 Mpix, yet captures so much more information! I think the DPxM are still behind medium formats. But when comparing with the 35mm big guns like Nikon D800E/ Sony A7R/ RX-1R who has 36 Mpix, I think Sigma DP2M hold up quite well, magically with its 16Mpix.
megapixel is just half of the equation. It’s about RESOLVING POWER. With Foveon sensor there is no interpolation like all other cameras that uses Bayer sensors.
How can 16 Mpix hold up against 36Mpix?
That’s about sensor architecture. >90% digital cameras today use Bayer sensors. Fujifilm has X-Trans. But they all use interpolation. A simple way to understand is, a 16Mpix Bayer actually contains 8Mpix green photodetectors, 4Mpix red and 4Mpix blue (some might vary). But in our monitor, a 16Mpix color image needs 16Mpix red + 16Mpix green + 16Mpix blue. you see the math doesn’t adds up, because Bayers uses interpolation to “guess” the missing pixels (plus some algorithm to sharpen the image). There’s why in 100% crops, Bayer sensor image are of limited sharpness (of course also depends on ISO, Lens, etc). Whereas in a 16Mpix Foveon sensor, there is 16Mpix red + 16Mpix green + 16Mpix blue. which maps 1:1 to the monitor, no interpolation needed, no fake pixels. That explains its faithful reproduction of every pixel color and details/ sharpness. And that’s why Sigma market it to be 46Mpix yet only 16 Mpix effective pixel (confusing, and fail to make people understand its power) .
To appreciate the full beauty of DP2M, click to see the full-res images. Among them, only the first image below cover image is a 100% crop – have you seen any 100% crops of that level of sharpness and detail? Look that those high-frequency fine lines! . It’s really shocking everytime I go home and seeing the photos on computer screen at full res 1:1. It’s just amazing.
So much about the GREATNESS of Foveon. Now everything has a cost, the DP2M sacrifice nearly everything else (except the lens) to achieve its magic. That includes:
– super short battery life
– very poor low light iso performance
– huge data that makes process and writing very very slow
resulting one of the most difficult camera to use.
The low light performance is a real limitation. In practice, I consider it one of those day-time camera. Its ISO performance falls so quickly to unusable images. Its ISO 400 has more noise than ISO 1600 for many m43 cameras. So you are stuck with ISO 200 or best to use ISO 100. With its f/2.8 aperture, day-light is almost a must. Does it mean ISO 400 and 800 is unusable? depends on your tolerance of noise. I have to say, given a increased noise in ISO 400 and 800, the 1:1 photo detectors are still giving a unique sharpness and details. And for B&W its probably still usable like when you use ISO 3200-6400 in other cameras. But don’t even think about ISO 1600 for DP2M.
Like other 36Mpix cameras like Sony A7R and Nikon D800E, the ultra details of DP2M requires you to hold the camera steadier than usual. A typical 1/focal length shutter speed formula doesn’t work. For DP2M’s 45mm eqv. I almost always use <1/125 shutter, so that the ultra-detail isn’t wasted by camera shake that i cannot see on the LCD. And yes, no stabilization. To improve this without the inconvenience of tripod, i found that a monopod is a great companion for DP2M. The monopod gives me roughly 2 stops stabilization which helps a lot.
For the same reason, your depth of field even at not-so-shallow f2.8 @ 45mm, must be carefully handled: I always use the “pin-point focus” mode, so that i use that tiny rectangle to focus on exactly where i wanted to. again you won’t easily detect your miss-focus at your LCD. Also, normally architectural or landscape shots we will stop down the aperture to make as wide DOF as possible. With DP2M’s poor high ISO and without tripod, there is only so much you can stop down, especially you should have shorter-than-normal shutter speed for the above mentioned reason.
The above 2 points I won’t consider the fault of this camera – its just the extra skills required to use high resolving cameras.
Summing up, unless you use tripod, it limits your to day light and not particularly easy for portraits. It’s definitely not a camera for everyone. Honestly, my first shootout of this camera make me want to ebay it out the other day, but once I see the image on computer screen – Jeezzzz.
Is it worth the struggle? Hell ya!
Happy Shooting 🙂