Sigma announces sd Quattro system cameras with two sensor sizes

Sigma announces the sd Quattro and sd Quattro H. The system cameras have an aps-c and aps-h sensor respectively. In both cases, it is a Foveon X3 chip with three layers. The cameras use the Sigma SA lens mount.

The new Sigma sd Quattro cameras merge the technology of the Sigma SD dslr and the dp Quattro fixed-lens compact cameras. The new cameras have interchangeable lenses, but no mirror. There will be two variants: the sd Quattro with aps-c sensor has a crop factor of 1.5x and the sd Quattro H has a slightly larger aps-h sensor with a crop factor of 1.3x.

Sigma uses its Foveon X3 sensor, which consists of three layers, for the new cameras. Unlike traditional sensors, which extract color information from a Bayer filter through interpolation, the Foveon sensor has a separate layer for each primary color. The top layer, which consists of four parts, contains four times as many pixels. Interpolation therefore takes place to calculate all color information, but less than with a Bayer sensor.

The aps-c sensor of the Sigma sd Quattro is 23.5 x 15.5 mm in size and the top layer has a resolution of 19.6 megapixels. Underneath are two layers of 4.9 megapixels each. The model with aps-c sensor, the sd Quattro H, has a chip of 26.6×17.9mm. The top layer has a resolution of 25.5 megapixels and the two layers below that have a resolution of 7.5 megapixels. Due to the multi-layered sensor design, the resolution is not directly comparable to cameras that have a traditional Bayer sensor. According to Sigma, the effective resolution of the sd Quattro is comparable to 39-megapixel cameras and the resolution of the sd Quattro H corresponds to 51 megapixels with Bayer sensors.

The cameras also get a ‘Super-Fine Detail’ mode, in which seven photos are taken. The seven different exposures are saved as an X3l raw file. With the Sigma Photo Pro software, this can be converted into an image with a large dynamic range. Since seven shots are taken, tripod work is required and this mode is only suitable for static subjects.

The sd Quattro has a maximum shooting speed of 3.6 fps and can take 14 photos in a row in RAW format before the buffer is full. With the sd Quattro H, the maximum speed is 3.8 fps and ten raw photos fit in the buffer. Phase detection with 9 focus points can be used for autofocus. In addition, it is possible to focus on the basis of contrast detection. The ISO range is from 100 to 6400.

The cameras have an electronic viewfinder with 2.36 million pixels. The effective resolution is probably 1024×768 pixels. The LCD on the back of the cameras consists of two parts. In addition to the 3″ LCD with 1.62 million pixels, a ‘sub-monitor’ is placed, on which information such as shutter speed, aperture and ISO value can be seen. The housing of the sd Quattro cameras is made of magnesium alloy and sealed against dust and moisture.

The choice for the SA lens mount is striking, because that mount is made for SLR cameras. Because the new sd Quattro cameras are system cameras without a mirror, a large empty space is created between the lens mount and the sensor. With a dslr, this space is used for the mirror construction. System cameras from other brands use a short lens mount, with the advantage that it is possible to use lenses from other brands with the aid of adapters. This is virtually impossible with the Sigma SA mount. Thus, only Sigma’s own lenses can be used on the cameras.

Sigma introduces a number of accessories along with the cameras. The Power Grip PG-41 offers space for two batteries, provides extra grip and offers control buttons for shooting in portrait mode. Like the camera, the handgrip is dust and water resistant. Sigma also comes with a flash, the EF-630, which has s-ttl technology for automatic exposure. A USB dock appears next to the flash, with which the firmware of the flash can be updated by the user.

When the cameras will come on the market and at what price is not yet known.