Sigma SD Quattro Digital Camera with 30mm F1.4 DC HSM

Product Information

Lastly, you'd better have a big memory card - the DNG files weigh in at around ~150MB each *. For comparison, uncompressed Raw files from the Nikon D810, Sony a7R II and Fujifilm GFX 50S weigh in at around 70MB, 85MB and 110MB, respectively (and two out of those three offer lossless compression to bring those sizes down anyhow). You can see the output from the Sigma is significantly sharper and contains a lot more fine details than the output from the Nikon. I have not normalised (i.e. resized) the output from the Sigma to match the lower resolution Nikon (when does a 36MP camera become a lower resolution camera!??). So if I resize the 39MP JPG from the Sigma down to 36MP, Sigma’s per-pixel sharpness would be even better. The sd Quatro H has a new option which helps open possibilities: DNG files. All of us using raw file editing programs can rejoice and not have to worry about conversions. However, the format has a lower bit depth than the .X3F format.

In use, the sd Quattro is a reasonably responsive camera, and the slow processing and write times that plagued the SD1 Merrill are gone. It’s not going to challenge similarly priced enthusiast DSLRs for speed, especially when used in its resource-hungry SFD mode, but it won’t leave you waiting much, either.There are two potential disadvantages of this approach. The first is, as you'd expect, the wasted space of building a mirror box for a camera with no mirror. The second, arguably more important downside, is that most DSLR lenses are designed and optimized for phase detection autofocus and they often perform poorly when asked to focus by contrast detection, meaning you have a wide choice of lenses but perpetually hamstrung performance. Sigma has tried to mitigate this by adopting on-sensor phase detection in the SD Quattro H. Okay, enough with the caveats. Opening these DNG files in Adobe Camera Raw is an almost surreal experience. You still get the absolutely astounding crystalline sharpness Sigma's cameras are known for, but now you can make any adjustment you'd ordinarily make to a Raw file, and with a decently powerful computer, it all happens in real time. No more making a small adjustment and waiting ten seconds (or thirty) for a full re-render. Sigma has also announced another camera for it’s mirrorless camera family, the Sigma SD Quattro H, which is very similar but with a slightly larger 25.5MP APS-H size (1.3x crop factor). The claimed equivalent resolution is 51MP.

I found the body pretty comfortable to hold, despite its weight and I was able to shoot sharp images a long way below 1/equivalent focal length, suggesting I had a fairly stable grip on the camera. The two main dials are well placed, meaning it was easy to set the aperture and exposure compensation. For the unconverted, it's a little more difficult. Even in its Quattro incarnation, Foveon sensors are challenging to shoot. The performance in all but the best light is poor by modern standards and, even at base ISO, there's less dynamic range to play with in processing than we've come to expect. But, with all that said, there's nothing on the market that produces such realistic levels of detail. System adoption The Sigma sd Quattro H offers a full range of advanced exposure controls via the Mode button on the rear of the camera, including aperture-priority, shutter-priority, manual and manual focusing, with three Custom modes so that you can save and recall your preferred settings. There are no auto-everything or scene modes on this camera, which is a veritable breath of fresh air at a time when most manufacturers are stuffing their cameras full of clever technologies that take control away from the user. The aperture or shutter speed are set by using the forefinger-operated control dial on top of the camera which encircles the shutter button, with a smaller rear control dial setting the aperture in the Manual shooting mode and exposure compensation in the other modes. There are 7 ISO settings available on the Sigma sd Quattro for both JPEGs and RAW files. Here are some 100% crops which show the noise levels for each ISO setting, with JPEG on the left and RAW on the right:Blame DxO Optics Pro. That product has never opened any DNG file created by Adobe DNG Converter or LR, no matter what camera raw file is used, so the Adobe-compatible Sigma DNG file was never going to be any different. The Sigma Foveon X3 Quattro CMOS doesn’t just mimic film, the underlying sensor architecture is layered like film emulsion. All of the sample images in this review were taken using the High JPEG setting, which gives an average image size of around 13Mb. The Sigma sd Quattro's maximum shutter speed is 30 seconds and there's a Bulb mode which allows for exposures of up to 2 minutes, which is good news if you're seriously interested in night photography. The shot below was taken using a shutter speed of 30 seconds at ISO 100. The X3 Quattro sensor is at the heart of what makes the SD Quattro H interesting and is, far more than any physical difference, the thing that most sets this camera apart from all its rivals.

The obvious appeal of using an existing mount is that the lenses already exist for it. Sigma produces SA mount versions of 39 of its lenses, which plausibly means the Quattro H has one of the widest choices of own-brand lenses of any mirrorless camera. Foveon X3 Quattro Sensor While the SD Quattro’s dynamic range appears to be not as good as the latest Nikon or Sony cameras, the camera has a Super-Fine Detail (SFD) exposure mode which basically shoot seven photos each at different exposure and the results are combined together as a huge X3I format file. (7 x normal raw file size) This mode is used to improve the dynamic range and also minimise the image noise. Downside of the SFD mode is that you pretty much have to use a tripod and you might also end up having some weird results when shooting a scene with moving objects. I absolutely love the feel of the SD Quattro’s body, and the DP range with fixed lenses is very different as well to the usual crowd. The Sigma X3F raw files are of the same resolution but Sigma Photo Pro using the Super-Hi export setting, the software can produce upscaled 16bit TIFF files at roughly 36MP or 7K.As well as the innovative sensor which I’ll get to in a moment, the SD Quattro maintains the Sigma DSLR tradition of having a removable IR cut filter. You simply take it out with tweezers.

All of the sample images in this review were taken using the High JPEG setting, which gives an average image size of around 15Mb.

Operating Conditions

People have asked DxO to allow Adobe DNG files, but no. They say, "We understand the issue with this format and here is an explanation: a DNG file cannot be used as just another RAW input file, since it does not contain all the calibration data Optics Pro uses when processing RAW files (especially, but not only, for the denoising algorithm). Therefore, even if Optics Pro could process DNG files without the data it requires, it could not achieve the same quality level as with an original RAW file, and we do not believe people who shoot RAW would be interested in such a substandard solution... This is the reason why Optics Pro only supports the DNG files generated by the cameras we calibrated in our labs..." There are two ways of looking at the sd Quattro. First, is it a realistic competitor for a similarly priced enthusiast DSLR or CSC? Sadly, the answer is probably not, at least for the majority of photographers; it’s difficult to recommend building up an SA-mount lens set to use with such a specialised camera. Landscape shooters happy to bolt it to a tripod and always work at ISO 100 might appreciate the unique qualities of the Foveon sensor, but it’s difficult not to conclude that the majority of photographers would be better served by an up-to-date APS-C DSLR or CSC instead. Almost any other interchangeable-lens camera will give faster autofocus and much better high ISO performance, and therefore increased shooting flexibility. The fact that its raw files can only be processed using Sigma Photo Pro is also a serious liability; this software is simply too slow and clunky to offer any kind of sensible workflow unless you only plan on processing a very limited number of shots at any given time. The CMOS result looks ‘smoother’ but look how many more colour tones are present in the Sigma shot.