master test L
ast year, Sigma’s DSLR line up consisted of one camera, the SD15. With a 4.5Mp Foveon X3 stills-only sensor it could hardly compete against mass produced 16Mp to 18Mp CMOS with HD-video. Sigma’s purchase of Foveon was clearly the make-or-break move. The sensor design and fabrication innovators brought many new technologies to the market but needed to supply many custom- ers; exclusive small-scale sales to Sigma wasn’t the plan. However, at the moment the knock-out punch should have been about to land, Sigma announced the SD1 – a camera not built for High Street retail appeal, but to deliver unprece- dented image quality for serious photographers. Four years of long delays between announce- ment and release may have dulled photo-technical press en- thusiasm for the 16 megapixel (X3, which means equal to over 40 megapixels of standard sensor). The SD1 – which despite the Japanese earthquake shipped essentially on-time – contin- ues Sigma’s unique use of the Foveon sensor and X3 resolu- tion; in this revision a 15.4Mp APS-C unit with a 1.5x “crop”. Earlier models of Sigma use a 1.7x crop and 3.3 or 4.5Mp sen- sors. In context, the new sensor has enough resolution for a 20 x 30" inkjet print, without any colour interpolation. This camera has no Anti-Aliasing filter, so good lenses can deliver incred- ible results; I know there are photographers out there making large prints cropped from 10- 12Mp Bayer sensors; this sort of resolution and accuracy will make those crops considerably higher quality.
The advantages and disad- vantages of the Foveon technol- ogy remain; smooth tones are represented with precision as any given pixel exists in isola- tion (no adjacent locations are used in calculating the colour and luminance), objects at dif- ferent distances are extremely
MASTER PHOTOGRAPHY 38
photography_
The Sigma SD1 DSLR may not seem an easy choice to make – but it offers medium format quality in return.
Sigma remains a camera best kept out of the dark.
The SD1 makes sense as a precision, high quality alterna- tive to a conventional APS-C body, with a very high price pre- mium to pay for a unique capa- bility. Despite having to handle files up to 70MB and carrying the same processing power as a Pentax 645D, the SD1 weighs 700g, has a body smaller than a Pentax K-5 or Nikon D300 with build quality easily the equal of any magnesium-bodied, weath- erproof system.
Colours from the Foveon sensor can be unexpectedly rich
well-separated. The camera’s natural gradations, crisp detail and distinctive colour render- ing generate stunning prints. Upscaling can be done without fear of emphasising the interpo- lation artifacts and fringing of a Bayer RGB-filter-array image. On the downside, the file sizes for the native output resolution are much larger (one reason Sigma tends to describe files as their luminance pixel data, rather than spatial resolution) and this relation- ship between the size and type of camera and the quantity of data gives the impression that the system is slow. It is, in fact, faster than any camera moving a similar quantity of information – it’s just producing a smaller, higher-quality output file from that source.
Without video capabil-
ity, live view or tethering, the SD1 fares very badly on the consumer-targeted comparison charts. Shooting speed from this compact body is between 3.5 and 7fps (the faster speed is
at half-res – still greater than the original SD9’s output) with a buffer holding seven full-size raw files. It’s not winning any friends in the spec-driven amateur market, even though the sim- ilarly-priced Leica M9 escapes widespread criticism for 2fps and 8 frames for considerably less data. It’s more than usable in the studio or for weddings and environmental portraiture, but you might not want to shoot a football match with it unless your skills are closer to the sports photographers of the 1970s.
Similarly, whilst the SD1’s sensor has made huge leaps in high ISO quality from the earlier type, Sigma have clearly felt compelled to push the bounda- ries of the spec and claim 6400. 3200 is certainly tolerable, with a bit of processing, and 100-800 is impressive, but if you’re criti- cal of your source material you won’t want to exceed 1600. In good light, 6400 can be used for faster shutter speeds but the
Some of the ergonomic touches border on exquisite; the grip design, with forefinger on the button, is one of the best I have ever encountered. Single-handed adjustments, with thumb and forefinger control, extend to ISO, meter- ing, focus point and exposure compensation – all confirmed in the viewfinder. The built-in flash rises high above the body, improving the variety of lenses you can use with close subjects. The technical specs away from the sensor are 1/8,000th shutter, 11 AF points, 77 segment meter- ing, CF card storage and a 98% viewfinder; all adequate. The new “Direct Image Sen- sor” has microlenses, but lacks an AA filter and as with past SD bodies, has a removable hot- mirror, making it easy and non- destructive to open the SD1 up to invisible Near-IR light (from a portraiture point of view, a less aggressive hot mirror and careful processing can yield smoother skin tones, as well as the ability to mix and match IR and visible).
The lack of anti-aliasing – a trait shared with MF backs and Leica’s M9 – allows the right glass to deliver exceptional clarity and resolution; unlike the Bayer sensor bodies it can do this without false colour moiré. Uniform textures and details, such as the weave of a cot- ton shirt, or intricate lace, are retained with a clarity that can only otherwise be achieved with
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44