New mirrorless Sigma sd sd Four and Four H with Foveon X3 sensor APS-C and APS-H

Sigma announced two new mirrorless cameras intended for the high-end market, sd sd Four models Four and H. The main difference between the two models lies in the sensor used; if one part is confirmed the use of Foveon X3 (alternative to the traditional ones matched to filltro Bayer), the first model provides for an APS-C cut while the second abnormal APS-H, the dimensions of which are 30% higher at 'APS-C but still lower than those of full frame. The ISO sensitivity ranges from 100 to 6400, lower compared to recent models of competition (Sony on all), but typical of the Foveon X3 technology (light must pass through three layers and not one).

Speaking in front of resolution to the Foveon X3 technology requires a few words: in its systems Four, Sigma uses the sensor design with three layers, where the upper one has a high and sensitive to blue shade resolution, while the two lower sees drop the resolution to 1/4 of the upper one, with sensitivity to the red and green tones. Sigma sd Four H has a 25,5Mpixel on the top layer and of about 6,4Mpixel for each of the two lower layers.

The arithmetic sum is a little more than 38 Mpixels, but Sigma declares a qualitative yield similar to a traditional sensor from 51Mpixel. The file created has pixel dimensions provided by the upper layer (something like a 6000x4000 pixels, a little more), and not those of a traditional 51Mpixel as may be the Canon EOS 5Ds from 51Mpixel, which generates files is 8688 x 5792pixel. This is to clarify a bit 'a pretty complex subject.

For the APS-C model, sd Four (without H), Sigma declares a sensor in which the top layer is a 19,6Mpixel, while the lower two of 4,9Mpixel each, with a qualitative yield similar to a traditional 39Mpixel.
Both models are made of metal alloy and are climate, as well as integrating an electronic viewfinder with 100% coverage of the scene. Provided a mixed autofocus system, which integrates components phase detection with other contrast detection. Some details are missing for now (it is an ad, not a marketing), which is why we only report what has been available.

To accumulate the two models is also a double rear screen (see gallery), which appears single machine off. They are therefore two adjacent display: a traditional for previews and consulting menu, the other joined, as if it were a "slice", in which the settings (similar to those found at the top of many SLRs are shown).

Sigma makes a strong attachment level choice, choosing to adopt the SA proprietary system long draw (that of the SLR Sigma and others); This greatly reduces the possibility of adopting third-party lenses via adapter, a choice of which more than a criticism will fall. Among the missing information is the price, which does not know anything yet.