Sigma does nothing like the others: family SME in the world of Canon, Nikon or Sony, the Japanese brand cultivates its difference. She has always made choices, more or less happy, but she has always made them. And has not stopped progressing, whether during the redefinition of its optical range, with the ART range in particular, at the excellent image-price quality ratio, or in its pursuit of perfect image quality with its compact DP Quattro, devices incorporating the new version of the Foveon sensor and on which the SD Quattro, the brand’s first hybrid camera, is based.

Sigma has already designed SLR cameras with Foveon APS-C sensors, SD, whose distribution and sales were confidential. This allowed the Japanese brand to acquire a know-how that is felt when you take the SD Quattro in hand: the manufacturing quality is simply impeccable. It is even so good that it is hard to imagine that such a quality 100% made in Japan could cost only 800 €!

On the ergonomic side, the choices are radical, not to say divisive – electronic viewfinder in the middle of the device, huge handle, line cut out underneath in a strange way, ignition button on the bayonet barrel, etc. If all these choices are not rational from the point of view of a reporter who would look for a camera with the perfect handling – it is far from being the target of Sigma – this can meet the needs of a studio photographer who is looking for a case with well-separated controls and a unique look.

And one thing is obvious: if Sigma did the same thing as the others, the brand would have a hard time standing out on the shelves. What the brand needs in front of the behemoths in the photo.

Foveon Quattro sensor, the other way

Unlike 99.9% of the CMOS sensors of our cameras and smartphones which use a so-called “Bayer matrix” sensor, Sigma devices are equipped with a unique sensor called Foveon. Unlike Bayer sensors where each photosite – incorrectly called a pixel – only codes for one color, each photosite of a Foveon sensor receives the colored information from the 3 red, green and blue channels.

When Bayer matrix devices use algorithms to reconstruct information from the two missing channels of each photosite by averaging the colored information from adjacent photosites, the Foveon receives all the information about each pixel. The Quattro version brings a new structure of the colored layers with a little less finesse in the red and green layers, but in the end we obtain the same type of images as for the Merrill generation.

Perfect on paper, Foveon technology has advantages as we will see, but the medal also has its downside. Even setbacks: the rise in high sensitivity is sorely lower than that obtained with a Bayer sensor (past ISO 400 it’s even the Bérézina), the reading speed of the sensor is slow – no burst of madness possible -, the lack of competition on technology does not facilitate innovations, especially in the field of image processing processors, video is so headache that Sigma removed functionality from SD Quattro and finally, to mention only the main setbacks, RAW files are huge and can only be edited by the awful Sigma Photo Pro.
With its shortcomings, we pay the image quality at a high price, but at least it is well presented (read below).

Direct view, the big blur

We have reviewed all Sigma compacts since the first DP1 and, since the Merrill generation, we have noted the extraordinary image quality at ISO 100 of these devices. All this to say that once you have understood and accepted the kind of device that a Sigma can be, you can only appreciate the extraordinary sharpness of the images it produces.

This finesse, this precision of the image is not felt when you put your eye in the viewfinder. The SD Quattro wrestles, at first glance offers a rather coarse image, which is then refined slightly when the point is made. But we stay very far from the same mid-range sights of current hybrids. In our opinion, Sigma has trouble processing the flux sent by the sensor in real time and therefore performs signal compression which harms the perception of sharpness.

Japanese brands are not very discerning about the technical details of their devices, this is, of course, only a guess. But given the good image quality of the shots already taken when looking in the viewfinder, we bet that this is the reason for this degraded signal. As the cameras are now real computers, it is hoped that Sigma’s software engineers will be able to improve the quality of the scene display in real time through a software update. Hopefully.

Absolute dive (in broad daylight)

We have already reviewed the Foveon Quattro sensor in the DP Quattro. Whoever equips this hybrid has the same attributes: the sharpness of the image at ISO 100 is simply breathtaking. It’s very simple, analyzed with a magnifying glass, the photos of this 19.6 Mpix sensor equal those produced by a super large 40 Mpix sensor case costing several thousand euros.

As usual, we encourage you not to take our word for it, but to see for yourself the quality of the images by viewing and downloading the high-definition photos from our Flickr album (photos from RAW X3F files developed in Sigma Photo Pro 6.4 .1 in TIFF then compressed in Jpeg q = 10 in Photoshop).

Yes, the SD Quattro is, in broad daylight and on still subjects, superior in terms of sharpness of image to any other reflex or hybrid even full format. Each leaf, each branch, each element of the image present in the area of ​​sharpness is revealed, cut, spring. More than stung, one has the impression that the image is chiseled. Once again, the Foveon demonstrates, in full light, its ability to bring out materials, volumes, textures. If reporters will not care about its slowness, studio photographers (portraits, products, etc.) and landscape photography enthusiasts will be more than satisfied.

Slow like a manatee

The manatee is, with its sirenian cousin the dugong, the only herbivorous marine mammal. It is big, slow and peaceful … like the Sigma SD Quattro. Bulky as we have already said, the SD Quattro is also slow in almost all areas: from autofocus to the time of recording photos on the memory card through the editing of photos in the software. Sigma Photo Pro computer. In short, the entire SD Quattro workflow is soft from the knee. Only its sober and very clear menu reacts quickly and well. Impatient hyperactive, go your way, you will go crazy.

What would be a disaster for the kings of liveliness that are the cameras of Panasonic, Olympus or Sony is, for Sigma only a distant constraint, given the target of this camera: art photographers with contemplative behavior . But even this admitted, it would still be fashionable for Sigma to put the package on electronics and software …

ISO: king at 100, disbeliever at 800

As we have seen, the image quality of the SD Quattro is at the firmament at ISO 100. Only unlike a conventional case, the degradation of the sensor performance in high sensitivities does not gradually deteriorate: it collapses from ISO 800. Even a conventional value of 400 ISO sees the first errors appear in a sensor which is struggling to gather enough light because of this three-layer sensor.

As awful as it is (read further), the Sigma Photo Pro software allows you to recover colored information from the RAW file that has been lost in the Jpeg from the camera. But even so, SPP cannot work miracles and the noise level remains really too high.

Black & white rendering: the silver touch

This is one of the paradoxes of this case: if the SD Quattro is the most digital device in its capacity to offer a color image with surgical precision, it is also, conversely, one of the best in its ability to produce black & white shots with silver rendering. It seems that this is, again, its Foveon Quattro sensor which, devoid of low pass filter and demosaicing routine, can best simulate a silver grain.

The black & white rendering and the management of its grain are controlled from the free Sigma Photo Pro software. Software we need to talk to you about …

Sigma Photo Pro or “patience is a virtue”

The proverbs on patience are legion and we guarantee that you will have time to learn them if you use Sigma Photo Pro (SPP). Available for free under Windows and Mac OS, this software is the only official way at present to edit the huge RAW files from Sigma cameras. The problem is that if Sigma is a beautiful photo brand, it is not an electronics engineer. If we add to this the lack of competition in the analysis of data from Foveon sensors – Sigma bought Foveon and it is the only company to use these sensors – we understand why SPP is not optimized.

And when we say “not optimized”, we remain polite: SPP is a real calf – sorry, a manatee, but it is a little bit like wit. On our big 3.4 GHz Core i7 4770 supported by 16 GB of DDR3 RAM, a large 512 GB SSD and a small Nvidia Quadro K600, opening, developing and exporting RAW files is not a slow operation: it’s maddening.

Allow ten good seconds to open an image, plus ten more to load the file at 100% (no, open images are not loaded at 100% …) and (at least) 10s more for each changes made such as exposure, sharpness, shadow correction, etc. The Quattro files are larger than those of the Merrill generation and progress in their editing is simply zero. It is high time that Sigma hired software specialists.

In the meantime, we will continue to learn all the virtues that patience brings …

The feat of made in Japan by Sigma

A small fish in an aquarium where the other actors are often industrial monsters, Sigma is a company with a very strong culture and conscience. So strong that certain choices, in particular the production of cameras, are not subject to the same imperatives of profitability as in big – the CEO of Sigma, Kazuto Yamaki, says that the production of camera is the pursuit of the dream of his late father, Michihiro Yamaki, founder of the company and that it only brings know-how in the production of optics. At a time when a range of devices can disappear overnight due to poor performance for a few quarters, this passionate vision is more than refreshing.

We are all the more amazed by Sigma’s ability to produce all by itself, in its corner and almost 100% in Japan, a box which offers, for 800 euros excluding optics, the same image quality at ISO 100 (or better) than a Nikon D810 at 3000 € with optics at 2000 €, necessary to obtain such a level of sharpness. The SD Quattro has faults (full), but its “image quality-manufacturing quality-price” ratio commands respect.

Sigma SD Quattro
Sigma SD Quattro
Sigma SD Quattro
Sigma SD Quattro
Sigma SD Quattro

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