Sigma sd Quattro Review

The Sigma sd Quattro is the new mirrorless interchangeable lens camera from Sigma, and replaces the SD1 Merrill, which was Sigma's Digital SLR camera. The sd Quattro features the same Sigma SA lens mount, making it compatible with all Sigma SA lenses. The sq Quattro features the same APS-C Foveon sensor as the dp Quattro series, and is available for £799 body only, or £999 with 30mm f/1.4 Art lens.

Sigma sd Quattro Features

The core of Sigma cameras is the Foveon sensor, something that is unique to Sigma, with no other manufacturer featuring a Foveon sensor. The Sigma sd Quattro uses the newly developed Foveon X3 direct image sensor (generation name: “Quattro”), as featured in the dp Quattro series.

The Foveon sensor features multiple layers to capture all of the colour information that visible light transmits, much like 35mm film, so that every pixel position on the sensor captures red, green and blue, compared to a normal sensor, which captures a single colour at each pixel, as shown below. 

The Foveon X3 Quattro direct image sensor differs from the previous Foveon sensor thanks to a new top layer with a higher 19 megapixel resolution, as shown below. This is said to give high resolution results, but with a lower resolution 4.9 megapixel green and red layer, that means image processing is said to be quicker and noise is also said to be improved. 

Sigma dp Quattro Sensor design (Image courtesy: Sigma)

Due to the sensor design, there is no low pass filter, and each pixel records full RGB colour information, thanks to a layered sensor, much like film. The previous Sigma dp Merrill series was said to give the equivalent of a 30 megapixel camera from a 15mp (x3) sensor, while the dp Quattro series is said to give the equivalent of a 39 megapixel camera when compared to a Bayer sensor camera, thanks to the 29.8 megapixel sensor (20mp + 4.9mp + 4.9mp), and full colour information for each pixel.

When Sigma introduced the sd Quattro, they also announced the sd Quattro H, which features a larger, higher resolution sensor, and we've run through the main differences between the two cameras below:

Sigma has added a new mode called "Super Fine Detail" - this mode takes a number of pictures, in a unique Sigma raw file format, and then you need to process this image to export it as a JPEG or the normal Sigma raw file. The mode is takes 7 shots for improved dynamic range with low noise. You can't view the result in camera, and the file is recorded with a .X3I extension. As the camera is taking a number of shots, a tripod is necessary. 

The rear of the camera features a 3inch screen, plus a secondary LCD display with camera settings displayed. There is a high resolution 2.36m dot electronic viewfinder (EVF) with dioptre adjustment, and 1.1x magnification. The camera has the usual P, A, S, and M shooting modes, plus 3 custom shooting modes. The camera does not feature built-in Wi-Fi nor a video mode. 

An optional battery grip, called the Power Grip PG-41 is available. The camera supports tethering with "Sigma Capture Pro" so that you can control the camera from your computer and shoot remotely, for example in a studio setup. 

A unique feature of the SD1 / Merrill series was the ability to remove the infrared filter from the camera, and this continues with the sd Quattro, meaning it's quick and easy to remove the filter, and use the sq Quattro for infrared photography (with the correct infrared filter to block visible light). 

Key Features

• 33 / 29.8 megapixel total pixels (19.6 megapixel top layer), 39 megapixel max image size
• APS-C Foveon sensor (23.5x15.5mm), 1.5x crop
• 3.6fps - up to 14 continuous shots, 5.1fps with Low image size (28 images)
• Sigma SA lens mount
• Dual TRUE III image processor
• New Super Fine Detail exposure mode
• Combination of Phase detection AF and contrast detection AF
• Focus peaking function, Quick set menu
• 2.36m dot electronic viewfinder (EVF), 1.10x magnification
• 3.0inch 1.62m dot screen
• Magnesium alloy body, with dust and splashproof design
• 14-bit RAW data, In-camera RAW processing
• Higher precision white balance (new algorithm)
• Colour modes, Monochrome options
• Custom bracketing display
• Electronic level
• USB3 port

Sigma sd Quattro Handling

The sd Quattro is a fairly large mirrorless camera, with modern styling that makes it look quite different to anything else on the market. It doesn't feature the typical SLR shape with raised viewfinder triangle, instead the viewfinder is off-set giving the camera a flat(ish) top plate. The flash hot-shoe is in line with the lens mount. The on / off button is in a rather unusual position, and it can take a while to find it when you first pick up the camera, but once you've found it, it is easy to get used to this, and it feels solidly made. The camera has a metal body, that feels extremely well-built with rounded corners and edges, and the placement of the control wheels on top are very slightly moved away from the edges meaning you don't accidentally catch them. 

The sd Quattro weighs 625g without the battery or memory card. This is slightly lighter than the Sigma SD1 / Merrill, which weighs 700g, but more than the Sigma dp Quattro cameras weigh, at between 395-500g including the lens.

On top is the dioptre adjustment dial, control dial, lock switch, shutter release with another control dial, QS (Quick Set) button, flash hot-shoe, plus on / off switch next to the lens mount. The buttons and controls feel good, and the spacing between some of the smaller buttons makes it easy to change settings without accidentally pressing the wrong options. The QS (Quick Set) button makes it easy to change settings quickly on the rear screen, and you can customise what options are displayed so that you can access your favourite settings quickly. 

There are 9 focus points, and you can also use the "Free move" focus option to move the focus point more precisely.

The menus are well laid out and clear thanks to the high resolution screen, and the different sections are colour coded. There is no built-in help, so it's advisable to familiarise yourself with the manual. The back has buttons for the display, a switch for the viewfinder / auto / monitor, a playback button, S/C (single / continuous) auto focus, AF/AEL lock, sub monitor light on/off button, exposure compensation, ISO, metering, mode, 4-way controller with middle OK button, menu and focusing point button.

You can switch the rear screen off if you want, and just use the small sub-display, and you can also switch this off, so nothing is displayed on the rear of the camera. The screen, secondary display, and EVF can be set to automatically adjust the brightness depending on ambient lighting conditions, or you can set it manually. The colour reproduction on the screen and EVF match each other, but the resolution is quite blocky. Viewing angles of the screen are very good, and visibility is quite good even outdoors. The EVF is a high resolution 2.36 million dot unit, with an impressive magnification of 1.1x making the view appear large, however the refresh rate from the sensor isn't very quick which makes the viewfinder appear jerky, and not very smooth, as well as being quite coarse.