May 2023

The big update this month, if one excludes the PhotoShop Beta, was that I obtained an unused Sigma DP3 Quattro at a really good price. I already own a DP1 but have been unable to obtain the DP0 or the DP2. I should mention that I also use a Sigma DP3 Merrill.

The Sigma Dp0 Quattro is a discontinued[ fixed-focal length APS-C digital point-and-shoot camera, announced by Sigma on February 10, 2015.

Like other cameras in the Dp0 Quattro series ,it features a 29-megapixel Foveon X3 sensor, but is said to produce images equivalent to that of a 39-megapixel bayer sensor camera.

The Dp0 Quattro has the widest focal length compared to other models of the Dp Quattro range, with a 35 mm equivalent focal length of 21mm.

PCMag called the Dp0 Quattro a "niche product", due to its fixed wide angle lens, with some quirks such as its uncommon grip shape, slow processing and writing per capture and battery life, but praised it for the quality of images produced, with its superior sensor and lens, giving the Dp0 Quattro a rating of 3.5 out of 5.

During the CP+ [jp] show held in 2015, USA Today did a first impressions review of the Dp0Quattro, which mentioned that the improved sensor on the dp0 Quattro had "faster processing times", compared to older Foveon-based cameras, but still pales in speed compared to other cameras in the market at that time. The camera is described with low lens distortion despite its wide angle lens but with poor battery life, with a conclusion that the camera is "an endearingly oddball".

The operation of the Foveon X3 sensor is different from that of the Bayer filter image sensor, which is more commonly used in digital cameras. In the Bayer sensor, each photosite in the array consists of a single light sensor (either CMOS or CCD) that, as a result of filtration, is exposed to only one of the three primary colours: red, green, or blue. Constructing a full-color image from a Bayer sensor requires demosaicing, an interpolative process in which the output pixel associated with each photosite is assigned an RGB value based in part on the level of red, green, and blue reported by those photosites adjacent to it. However, the Foveon X3 sensor creates its RGB colour output for each photosite by combining the outputs of each of the stacked photodiodes at each of its photosites. This operational difference results in several significant consequences.

Because demosaicing is not required for the Foveon X3 sensor to produce a full-colour image, the colour artifacts ("coloured jaggies") associated with the process are not seen. The separate anti-aliasing filter commonly used to mitigate those artifacts in a Bayer sensor is not required; this is because little aliasing occurs when the photodiodes for each colour, with the assistance of the microlenses, integrate the optical image over a region almost as big as the spacing of sensors for that colour. On the other hand, the method of colour separation by silicon penetration depth gives more cross-contamination between colour layers, meaning more issues with colour accuracy.