It's been ages since we reviewed a Sigma DSLR camera, the last model being the not-so-impressive SD10. Fortunately, its replacement, the SD14 is a somewhat different beast, although it still uses a Foveon image sensor. For starters, it's more compact and 85 grams lighter than the SD10. It's also the first Sigma DSLR capable of shooting JPEG files as well as X3F raw files.
Sensor
The Foveon X3 direct image sensor used in the SD14 is a third-generation unit that's quite different from the CCD and CMOS sensors in other cameras, although it's built with CMOS technology. A 1.7x field-of-view crop applies as it did with earlier Sigma DSLRs. Instead of producing colour information by filtering photosites through a Bayer colour array, it is structured in three layers, rather like colour film.
The layers of photosites are embedded in silicon and take advantage of the fact that red, green, and blue light penetrate silicon to different depths. The bottom layer records red, the middle layer records green, and the top layer records blue. This structure allows image data for each colour to be extracted from the related layer without requiring filtration. In theory, it should allow the sensor to gather more colour information, thereby producing sharper pictures, more accurate colours and fewer artefacts (particularly moiré patterns). And, because no colour interpolation is required to produce the final picture, the camera should be faster and more responsive.
Foveon's technology has evolved since its first DSLR sensor was used in the Sigma SD9, which was launched late in 2002. As well as delivering higher resolution, the SD14's sensor and image processor can produce JPEG files This is a 'first' for Sigma's DSLRs. Four JPEG recording modes are provided: Super High (4608 x 3072 pixels), High (2640 x 1760 pixels), Medium (1776 x 1184 pixels) and Low (1296 x 864 pixels), covering most photographers' requirements.
In Super High mode, JPEG images are output as 13.9-megapixel files, ranging in size between 4.5MB and 7.6MB, depending on the amount of detail in the shot. X3F raw files start off as three layers of 2640 x 1760 pixels with a file size of between 14MB and 17.5MB. When converted into 16-bit TIFF images with the bundled software, they still have dimensions of 2640 x 1760 pixels but the file size has increased to 25-27MB. Obviously the colour interpolation used to produce the JPEG files accounts for the difference in pixel dimensions between the JPEG and raw image files.
Build and Design
The SD14's body is strongly constructed with a rubberised grip that has an indentation for the middle finger and is big enough to suit users with large hands. With the supplied lens attached and battery and CF card loaded, the SD14 weighs a hefty 1.275 kg. Overall, it's a nice camera to hold and has a reassuringly solid feel. The shutter button is well-positioned and there's an indentation on the rear panel to fit your thumb. An AF-assist light is located between the shutter button and the pentaprism housing on the front panel, while the self-timer light is right of the lens mount and the lens release button is below it, level with the mounting flange.
The top panel carries two dials: a Mode dial with P, A, S and M settings and a 'D-Dial' carrying the power-off switch, single and continuous drive settings, 2- and 10-second self-timer modes, mirror lock-up and auto bracketing settings. The pentaprism hump lies between these dials and carries a pop-up flash and hot-shoe. The pentaprism itself is an improvement on the earlier cameras, being not only larger but also brighter - although it's still not as bright as some competing cameras.
A slider above the viewfinder allows diopter adjustment and the viewfinder has a wide, hard rubber eyecup. The viewfinder covers 98% of the sensor's field of view and has a magnification of 0.9x, which is quite impressive. Right of the Mode dial is a small data LCD and in front of it sits the shutter button, which is surrounded by a knurled Command dial.
The rear panel has a pretty standard arrangement with the 2.5-inch LCD monitor (another improvement on earlier Sigma cameras) stationed below the viewfinder. Its resolution is relatively low for a modern DSLR and it doesn't do justice to the images produced by the camera. Brightness and contrast adjustments are provided. Left of the monitor is a vertical array of five buttons that access the Menu, Playback, Info, Modify Images and Delete functions. A function button above this array lets users access the metering pattern, AF mode, flash synch mode and extended ISO settings.
To the right of the LCD monitor is the arrow pad and, above it, a Quick Set button control that accesses the ISO, quality and white balance settings. Pressing this button calls up four functions as a display on the LCD. Laid out on the vertical axis are the ISO and white balance settings, while the horizontal axis handles the file format (raw or JPEG) and pixel dimensions. Three levels of JPEG compression are provided - a first for a Sigma DSLR. These settings are all slow to use because you have to toggle sequentially through several pre-sets to find the one you want.
The Function button, which sits left of the viewfinder eyepiece, works in a similar fashion to the Quick Set button and you have to step through a number of adjustments and hold the button down while turning the dial to make your selection. AE lock, exposure/aperture compensation and AF point selection buttons plus a + and - controller cluster in the top right corner. A rubber pad with a contoured thumb rest is located between these buttons and the arrow pad, while the CF slot cover slides out on the right hand side. This cover has no latch but it's textured to make it easy to open and locks into place quite securely (although no environmental sealing is provided).
The rechargeable battery slots into the camera base in a traditional fashion, while the strap lugs are located well out of the way of users' fingers when they are resting on the top edge. A removable dust protector has been placed in front of image sensor to prevent dust from reaching the imager and the new camera boasts an easily accessible mirror lock-up control.
Controls
Instead of a single menu that accesses several pages of settings, three ways of adjusting to camera controls are provided. Because there's only one Command dial and several functions require you to turn it while simultaneously pressing a button, the SD14 can often be a bit laborious to operate. Consequently, it's easier to adjust the JPEG compression settings than change the metering pattern or flash sync mode.
The Function menu.
The main menu is somewhat counter-intuitive but covers items that are mainly included in the set-up menus of other cameras. Unfortunately, its font size is small and the colours used are less visible than you would like. Some buttons, notably the Modify Images (which lets you mark, protect and rotate shots and activate slideshows) and magnification buttons only work in playback mode.
The Main menu.
Five DM (Distance Measurement) points are used by the AF system with sensors located in the centre, left, right, top and bottom of the field of view. The centre point has cross hairs for improved accuracy. This arrangement is simpler than the AF systems of some competing cameras but seems to work as well as the test camera's AF system was fast and accurate in bright light and only a little slower in dim conditions. However, we had to switch to manual focus for our long exposure tests after dark because subject contrast was too low for the AF system to use. Manual focusing was straightforward, largely because of the supplied lens whose focus ring moved smoothly and securely.
The SD14 also offers full manual control over exposure levels and has an over- and under-exposure indicator. Program shift is available, along with +/- 3EV of exposure compensation and exposure bracketing in 1/3EV increments. Centre-weighted, evaluative and spot metering are supported and, according to Sigma, the shutter mechanism is rated for 100,000 cycles.
White balance settings include auto plus six pre-sets (sun, shade, cloudy, fluorescent, tungsten and flash) and a Custom mode - but no facilities for fine-tuning settings. The sensitivity range is also limited to ISO 100-800 with an extended setting of ISO 1600. Adjustments can only be made in full EV steps. Shutter speeds range from 30 seconds to 1/4000 second with a Bulb mode that is limited to 30 seconds (which won't suit astro-photographers). Flash synch remains at a relatively slow 1/180 seconds.
Index playback.
Interestingly, the SD14 has more dedicated controls for reviewing shots than shooting functions. The new camera is compatible with more than 40 Sigma lenses and several dedicated Sigma flash units. And, unlike its predecessors, it comes with a rechargeable lithium-ion battery, which claims to support up to 500 shots per charge.
Software
The camera is supplied with Sigma Photo Pro 3.0 software, which combines a fairly average file browser with a better-than-average raw file converter. The browser has the usual folder tree in a narrow column on the left side, with the rest of the desktop taken up by a lightbox-style window containing images from the selected folder. Each image is identified by its file name and tagged to show whether it's a JPEG or X3F raw file.
The desktop for Sigma PhotoPro 3.
Five thumbnail viewing options are provided: mini, small, medium, large and thumbnails with details (which displays basic image metadata). You can elect to view only the JPEGs, X3F raw files or TIFF images or have all three displayed together. You can also rotate, mark and lock selected images when you want to identify or protect shots you really want to keep. The software also lets you delete and print images and display slideshows in the main window. Facilities are also provided for renaming individual shots and batch renaming as well as selecting one or multiple images.
Image Management facilities. (Source: Sigma)
Double-clicking on an image opens the file in the editor/raw converter, which provides three adjustment modes: X3F (for raw files) or File (for JPEGs), Auto and Custom. With X3F selected each image is displayed as it was captured by the camera. Moving the selector to Auto automatically adjusts the shot while Custom allows you to make your own adjustments by clicking on the Adjustment Controls tag at the upper right corner of the pane.
White balance adjustments.
The Adjustment Mode window contains sliders covering exposure, contrast, shadow and highlight detail, saturation and sharpness. These settings can be saved for subsequent use on other raw shots but you can't save settings for JPEG and TIFF files. A colour wheel is provided for tweaking image colour and an eyedropper lets you display RGB values for any point in the image or neutralize the hue of a neutral colour with a colour cast. There's also a small RGB histogram and adjustments to set the shadow and highlight values for the warning masks (which can be turned on and off via a checkmark box).
Highlight and shadow warnings.
White balance adjustments are provided for X3F raw files, replicating the settings provided in the camera. However, the custom setting is replaced by an Original setting which restores image colours to the 'as shot' values. The Monochrome setting in this menu is non-destructive and you can restore colour and adjust white balance after processing an X3F file to create a B&W image. Clicking on Save Image As opens a window that allows you to select the source images, adjustments modes, processing settings (output image size, colour space, file type and JPEG quality) and the destination folder. There's also a button on the main window that lets you replace the stored settings in an X3F file with adjusted values.
Image saving options.
Sigma Photo Pro 3.0 also provides a tool for verifying the brightness, gamma and colour of your monitor, which is best used as an adjunct to Adobe Gamma. It's no substitute for proper monitor calibration but certainly better than nothing and may help novice users to obtain good-looking pictures on their PC screens.
Performance
Colour was the most impressive aspect of the test camera's performance. In all our test shots hues had a greater depth than we've seen from most of the DSLRs we've reviewed. Tonal subtlety was also competently recorded and there were few situations when the camera failed to capture a full dynamic range - especially with raw shots.
Imatest produced some interesting graphs from our test files and showed the supplied lens to suffer from slight edge softening. This defect isn't noticeable in shots unless they are enlarged to 200% or more, where traces of coloured fringing become visible. Interestingly, Imatest showed lateral chromatic aberration to be low. Colour accuracy was average for a DSLR but high levels of saturation were recorded for reds and yellowish-greens. Some hue shifts were also recorded.
The auto white balance setting on the test camera had the usual problems with incandescent lighting and didn't fare much better with fluorescent lights. Only the custom measurement mode produced acceptable colour reproduction. Flash performance was varied, with the best results coming from ISO 100 and ISO 200 settings. Flash exposures taken at ISO settings of 400 and above were generally over-exposed, suggesting some problems with the TTL flash metering system.
Overall, the SD14's shutter and AF systems were quite responsive. However we measured an average capture lag of 0.4 seconds, which reduced to less than 0.1 seconds with pre-focusing. It took approximately two seconds to process and store a high-resolution JPEG shot and just over nine seconds for a raw file.
In continuous shooting mode, JPEG shots were recorded at 0.3 second intervals and raw files marginally slower. The buffer filled after six raw files and then took just over a minute to clear.
Conclusion
Sigma's SD14 is an interesting camera that is most likely to appeal to photographers who prefer to use manual controls and shoot raw files. It will also suit photographers who want rich, eye-popping colours, subtle pastels and delicate tonal nuances - but they'll need to work hard to obtain the best results. The supplied Sigma Photo Pro 3.0 software is a good starting point for processing X3F raw files but we suspect most users will opt for a third-party application that offers a wider range of adjustments plus useful functions like cropping and straightening.
Relative to other DSLRs on the market, the SD14 is pretty pricey. Potential purchasers will need to weigh up the advantages of this camera against the many functions that are either missing or limited when compared with DSLRs from some other manufacturers.
IMATEST GRAPHS
SAMPLE IMAGES
Close-ups.
Strong backlighting.
Colour.
Image sensor: 20.7 x 13.6 Foveon X3 (CMOS) with 14.6 million colour photo detectors (2652 rows x 1768 rows x 3 layers)
Lens mount: Sigma SA
Focal length crop factor: 1.7x
Image formats: RAW (12-bit, lossless compression); JPEG
Image Sizes: 4608 x 3072, 2640 x 1760, 1776 x 1184, 1296 x 864
Shutter speed range: 30 to 1/4000 second plus Bulb up to 30 sec.
Self-timer: 2 and 10 second delay (selectable)
Image Stabilisation: n.a.
Dust removal: Removable dust protector in front of image sensor
Exposure Compensation: +/- 3Ev in 1/3 EV steps
Focus system: TTL phase difference detection AF
Focus modes: Single, Continuous with Predict Function, Manual focus.
Exposure metering/control: 8-segment TTL full-aperture metering with evaluative, centre-weighted & spot metering; P, A, S and M exposure modes
Colour space options: sRGB, Adobe RGB
Custom functions: n.a.
ISO range: ISO 100, 200, 400, 800 (1600 with extended mode)
White balance: Auto, Sunlight, Shade, Overcast, Incandescent, Fluorescent, Flash, Custom (measurement)
Flash: Built-in, pop-up flash, GN 11, coverage to 17mm lens; S-TTL metering; +/- 3EV adjustment in 1.3Ev increments
Sequence shooting: 3.0 fps for 6 frames in Hi mode; 12 frames in Med mode, 24 frames in Low.
Storage Media: CompactFlash Type I/II or Hitachi Microdrive
Viewfinder: Eye-level pentaprism, 98% coverage
LCD monitor: 2.5-inch low-temperature polysilicon LCD with 150,000 pixels
PC interface: USB 2.0
Power supply: BP-21 Lithium-ion rechargeable battery
Dimensions (wxhxd): 144 x 107.3 x 80.5 mm
Weight: 700 grams (body only)