Sigma SD1 – Production Model Review

Sigma SD1 – Production Model Review

sd1Sigma’s new flagship digital SLR, boasting a massive 46 MP Foveon image sensor, is causing quite a stir amongst the photo community. Richard Kilpatrick gets his hands on a sample and tells us what he thinks.

The Sigma SD1
The SD1 is something of a reality distortion device, in that it’s deceptively basic at first glance. It weighs just over 700g and has few buttons or external interfaces, it is slim in a way that brings to mind classic Olympus SLRs. Few DSLRs really match those dainty little film bodies of the ’70s and ’80s, but put the SD1 next to even an SD15 and it looks somehow more elegant. The design has stepped back from the utilitarian, functional SD cameras that preceded it and has become architecturally sophisticated, the base plate tapering (yet no deeper than a compact DSLR like a D5000 or K-5; it’s not a visual trick to mask bulk). The grip has a flat edge and dominant scuplting, using the shallow body to good effect despite an overall depth similar to the SD15. The grip is also marginally slimmer than the SD14/15 design, lending a feel of space to the front of the camera.
The thumb location and control surface of the back is elegantly curved, reflecting the shape of a human hand. One of the less popular decisions on the camera, the removal of the top-plate LCD, gives space for a control wheel that can be turned in sweeping movements, rather than incrementally tweaked through an aperture in the body. With two wheels, a logical and intuitive layout of buttons has been adopted; a slightly clumsy looking exposure button (almost as large as, and next to, the shutter) makes astonishingly sound ergonomic sense as a single movement combines with the rear wheel to make adjustments to compensation easy. Similarly, AF point selection can be accessed both by the rear Function LCD setup and the direction buttons, or by holding the dedicated button on the rear and scrolling with the front wheel. The camera already looks sparse compared to feature-laden DSLRs, but if anything Sigma could have stripped it back even further and forced the user to rely on menu selections.
Sigma SD1 rear panel
The LCD panel is 450,000 pixels, and has a good viewing angle.
Mechanical controls follow the recent Sigma design, with Drive Mode and Program Mode wheels. Drive Mode covers single shot, continuous (7fps at the highest speed, lowest resolution mode – still a higher resolution than the original SD9 – or about 3.5fps in full resolution raw mode), timer delay of 10 or 2 seconds, Mirror Lock Up and Auto Bracketing. The Program Mode wheel no longer looks so sparse, having gained three Custom Mode positions. The viewfinder matches Sigma’s previous offerings, with good brightness for an APS-C body and 98% coverage – the LCD strip shows frames remaining in the buffer as well as relevant information when making adjustments to ISO and Metering via the wheels. Whilst Sigma’s original “Sports Finder” is still missed, the smaller prism leaves room for a decent pop-up flash.
The 11 AF points illuminate when selected, and the focusing screen has a pleasing texture, making judgement of manual focus easy. At the moment no optional screens are available.
The typically Sigma-quiet shutter offers speeds range from 1/8000th second to 2 minutes in Extended Mode, with flash sync at 1/180th (curiously reported as 1/200th in EXIF, a Bulb exposure in the wrong mode will also do this), the metering is 77-segment evaluative with four metering modes, there are 11 AF points. So far, it’s a good camera, with improvements in every regard. Electronically though, this is a digital camera and the exposure-related aspects of operation are not yet half the story.

The SD1 features Sigma’s first all-new sensor since 2006; a 15.4Mp Foveon X3 unit (as Sigma now own Foveon, the  Foveon X3 logo has gone from the camera and the sensor is now referred to the “X3 Direct Image Sensor” delivering a final file of 4704 x 3136. Sigma User readers don’t (I hope) need to be reminded of Foveon’s 3-layer technology, and new readers can carry on without the need for it to be explained because this is Sigma’s first camera which isn’t at a native resolution disadvantage. If you want to know more, this article explains it. For now, the SD1 is an APS-C camera of good resolution and dynamic range which offers unparalleled image quality due to a unique (to Sigma) technology. That technology then allows greater quality of enlargements, sharper and more detailed crops, and more natural reproduction of textures and shading.
If you insist on comparing wildly different technologies, then the SD1’s sensor is claimed by Sigma to be comparable to a 30Mp Bayer CFA type; with a new generation of higher resolution APS-C sensors inevitably waiting in the wings, this argument is going to run and run.
Lacking a low-pass filter as well as the need to demosaic the image, the SD1 resurrects the old debates about moiré (not colour moiré, which is a function of Bayer demoisaicing, but the visual effect of breaking adjacent curves and angled lines into uniformly spaced and shaped elements) and ultimate sharpness. For the pixel peepers, the SD1’s ability to reproduce the finest details is a momentary pleasure – the real world advantages that last for a photographer are natural, realistic images with depth. The camera’s native resolution is sufficient for a 20″ x 13″ print at 240dpi; at the more common base resolution for output it’s a 26″ x 18″ without any enlargement. In other words, if you had a projector with enough pixels, you could blow it up to screen resolution or 72dpi and have a 1:1 pixel relationship for a 65″ x 43.56″ display…
And this is all before taking into account the purity of the source file. Sigma fans will already be used to the idea that a 4.5Mp file can be printed at 20 x 16″ without any real issues through simple bicubic interpolation – smoothing works, details are enlarged without any flaws, any false colour interactions introduced or emphasised. Even a medium format system with traditional CCD Bayer cannot withstand that sort of treatment; their benefits derive from taking a large enough file not to need it. The enlargement limits of the SD1? Who knows. A double-size export from SPP 5.0 yields a near 60Mp image, or 180dpi 53″ x 35″. More sophisticated routes will give better results, but as with the double size exports from the DP or SD14/15, it’s a perfectly acceptable, detailed result.
Having said that, the technology does involve different technological challenges to traditional Bayer sensors – not least the amount of data captured. The total capture of 15.4Mp over 3 layers results in a 40-55MB file, the equivalent of 46Mp worth of data in Bayer terms; recording twice as much green information and four times the amount of red & blue data. The compact chassis of the SD1 contains as much processing power as a Pentax 645D (they’re even using the same basic platform for processing though tailored for each customer), and the 3.5fps burst speed exceeds any current 46Mp system. Sigma are really pushing the boundaries of simply moving data around, in a package that weighs no more than a consumer DSLR – the SD1 is comparable to the smaller magnesium bodied systems such as the Pentax K-5.
Getting the data onto the cards – Type 1 UDMA CompactFlash, rather than the SDHC cards used by the other TRUE-based Sigmas – takes roughly 70-90 seconds to empty a full buffer of raw+JPEG files; you can use the camera controls after the first couple of seconds and an individual frame takes about 10-14 seconds to write (the initial frame after a burst of 7 can be taken after four seconds). JPEG files are considerably smaller, and a full 7-frame burst will write fast enough to effectively be 8 frames, and will fully empty the buffer in 19 seconds or so. Card type will affect the performance, these figures are with 300x cards. As mentioned on the previous page, the Low resolution mode is entirely usable and allows more shots in the buffer whilst also taking less time to write an individual file.
Helping with the SD1’s usability and on-paper spec, Sigma have increased the available ISO ratings, with 100 to 6400 now available – and the raw file options, whilst unchanged in terms of high, medium and low resolution now produce sensible results for many applications at the lower settings. In fact, the 3.6Mp “low” resolution format is a step above the SD9 and entirely usable for reproduction and online publishing, and offers a useful increase in shooting speed with 15 shots in the buffer and 7fps possible. The noise levels from ISO 100-1600 are excellent; at ISO 3200 the familiar green “blotch” pattern begins to emerge. ISO 6400 is really only usable for monochrome conversions at this stage; later firmware may improve that as it has with the DP series.

Any digital camera review online is going to fall into a trap of “technical” vs. “visual” capability and the audience’s perception. If your monitor isn’t calibrated correctly, don’t immediately assume that the SD1 results are incorrect. Most reviewers know their kit and will offer in the text an evaluation of products against other products.
As such, these are images so you can quickly see the full “composition”; full size sRGB exports are linked in the caption text – these will open in a new window.
100 ISO, 150 OS Macro at F14; this shot and the next were done with an elderly ringflash solution that is not controllable!

For a colder appraisal of the SD1, some straightforward ISO and resolution tests follow – ISO 100 through 6400 at full resolution, full resolution saved at low-resolution size, and low resolution. There’s no point comparing the medium resolution at this point, as there’s no performance advantage to be had by using it.
These files have been treated in SPP to reflect the best you can easily get – so noise reduction does change from shot to shot, in that ISO 100-400 have none applied, ISO 6400 has maximum applied. Sharpening is -0.5 in all cases.


ISO 100 – Full Image, Above, 100% Crop, Below. Standard Colour.


ISO 200 – Full Image, Above, 100% Crop, Below. Standard Colour.


ISO 400 – Full Image, Above, 100% Crop, Below. Standard Colour.


ISO 800 – Full Image, Above, 100% Crop, Below. Standard Colour.

ISO 1600 – Full Image, Above, 100% Crop, Below. Standard Colour.

ISO 3200 – Full Image, Above, 100% Crop, Below. Standard Colour.


ISO 6400 – Full Image, Above, 100% Crop, Below. Standard Colour.



At the time of writing, the only way to process the files produced by the SD1 is to use Sigma’s own software. Sigma Photo Pro has been around as long as the SD range, though it’s undergone a number of significant changes under the hood it has crucially managed this near decade of existence without seemingly evolving beyond that initial need to simply get the files into a more usable format (specifically 8 or 16-bit TIFF, or JPEG). Sigma Photo Pro 5 has been given a facelift, and processes the files from the SD1 in a two-step style in order to present a full image quickly, and allow inspection of full resolution. Auto adjustments are less obviously made, with the sliders rarely moving from their central locations (and the image being left very much “as shot”, and frustratingly for a camera which can suffer a reduction in image quality, the noise and sharpening still default to a certain level rather than 0 (or better yet, an amount that relates to the ISO setting on the camera).
SPP5’s adjustment bar – left – remains visuaully very similar to previous versions. However, the adjustments are even less obvious – where 4.2 required -0.5 sharpening for most 4.5Mp files, the “Sharpness” control appears to be defaulting to a very different position again and logically, it should have a “Zero” position that really is zero – either to allow softening of the file by applying a negative adjustment, or user-controlled sharpening.
The exposure, contrast, highlight and shadow controls remain very usable, with the excellent highlight retention of the SD1 being particularly useful. Aggressive use of the controls can tend to an HDR-like effect for the picture.
X3 Fill Light similarly remains incredibly useful – and as a Sigma innovation (in terms of applying the effect to raw files) introduced in 2003’s Sigma Photo Pro version 2, was one of the defining processes that contributed to the early “Foveon Feel” impressions that people got of the SD9.
SPP5HistogramIf anything, SPP5 – with colour space bugs, curiously dark text under the icons, a tendency to spin the beach ball on the Mac and a very limited featureset – is the worst aspect of using the SD1. Previous versions, with smaller files to cope with, had been more than adequate; it feels very much as if the software has simply got too much to deal with, without having the UI refinement to mask the process.
Fortunately third party support for the previous cameras was quick to emerge from Adobe, whilst SilkyPix recently introduced support as well; SD1 users will be waiting eagerly for more sophisticated solutions.
Unlike the DP series and SD models previously, the SD1 is a premium-priced camera, and Sigma would do well to follow Leica’s lead in including Adobe Lightroom as a processing solution when support is implemented. If not at source, then perhaps the importers or dealers could look at special offers to include it.
At the moment, the workflow in SPP 5 is very much geared towards getting your file out as a 16-bit TIFF then working with it in alternative applications, Even support for a DNG raw export would be better.

Sigma have opted to once again leave the X3 sensor’s video capabilities out, though there are hints that the new sensor is extremely good at HD video (Foveon sensors are, on the whole. excellent video capture devices).  Perhaps to save space in the firmware and reduce the demands on the processing pipeline, in-camera processing is restricted to colour and sharpness treaments; there are no lens correction, art or blurring effects to be found here. Perhaps of more concern to working photographers, the SD1 still lacks tethering capability, leaving the options for a studio workflow restricted.
There is also the matter of cost. The SD1 is uniquely talented. It’s also priced at £6199 in the UK currently. The thing is… there’s just nothing like it. If any camera user were given a choice to have their platform of choice equipped with uninterpolated, wide dynamic range capture – what would they be prepared to pay? That Nikon D300 or Canon 7D, but with no more Bayer and low-pass filter effects to reduce the quality of the final image?
You simply cannot get this anywhere else, and if you want that honesty in your images, that final quality, the premium is no greater than that of buying the highest speed “professional” bodies from Canon or Nikon, or the high quality optics of Leica. It’s easy to get lost in the weighing up of value-added features, but the cameras targeted at outright quality simply don’t place an emphasis on these things. Leica, Hasselblad, Phase One, even Canon & Nikon’s top-end bodies – no video. No effects. Just great pictures.
And that’s what the SD1 is all about. Offering an unadulterated relationship between your vision, the lens and the end result, with as much accuracy as a digital capture can offer.