Sigma's limited range of DSLRs use a different kind of sensor versus most other manufacturers. Called a Fovean X3 sensor, it uses very different technology than the usual DSLR sensors.
Foveon sensors have three sensor layers, which measure one primary color each (red, green and blue). An image is produced by combining these three layers to produce a mosaic of square tiles. The camera uses a lower resolution, but it captures far more detail than other DSLRs. The SD15 is a subtle upgrade to the SD14. But is the SD15 a legitimate rival to more mainstream manufacturers?
Description
- Resolution: 14.06 effective megapixels Fovean X3 sensor (4.7MP actual)
- ISO: ISO 100-1600, expandable to ISO 50 and 3200
- Focusing: 5 AF points
- Flash: Built-in pop-up flash
- LCD Screen: 3-inch LCD panel, 460,000 pixels
- Battery: Li-ion Battery Pack BP-21, Battery Charger BC-21, AC adapter SAC-4
- Dimensions: 5.67 x 4.22 x 3.17 in. (144 x 107.3 x 80.5 mm)
- Weight: 23.99 oz. (680 g) (no battery)
Pros
- Exceptional sensor producing stunning images
- Slightly "retro" design
Cons
- Confusing controls
- Feels crudely made
Build Quality
The Sigma SD15 is simply designed, which is especially appealing to those who yearn for simpler times and don't want to be faced with a host of different buttons! However, it is made of cheap plastic, and it feels crudely put together. For the price tag, I would expect this camera to be made of far more substantial material.
Controls
The SD15 only has one control dial, meaning that you need to hold down the exposure compensation button to switch between shutter speed and aperture. The control dial is a little stiff to use, but it is simple with only four modes -- Program, Aperture Priority, Shutter Priority, and Manual. For those used to the simplicity of film cameras, this will be a joy!
ISO, metering modes, and focus point selection buttons all are located at the top right on the back of the camera. It's great that the Sigma has these shortcuts, but they are quite easy to press by accident.
The controls themselves are rather complex. There's a "Quick Set" button, which lets you change file formats, white balance, image quality (when shooting JPEGs), and photo style. However, there's also a "Function" button, which allows you to select the flash and AF modes. It displays a focus grid showing the selected AF point, along with other settings, such as ISO, shutter speed, and aperture.
Finally, there's another screen which shows all the same settings as above, activated by pressing the "i" button by the LCD screen. It's all rather confusing, and it will certainly take time to get used to.
Image Quality
If you've never seen a camera with a Fovean sensor, you'll be amazed at the quality it can produce.
Each individual pixel is pin-sharp, and the amount of detail captured is extremely impressive. At base ISO, there is no noise at all, but it does increase as the ISO goes up. Unfortunately, the noise increases far more obviously than in other DSLRs with conventional sensors.
Overall, images seem to have a lot of contrast, but it doesn't negatively affect the photo quality, as images end up with rich colors and lots of saturation.
On the downside, the camera can't shoot RAW and JPEG simultaneously. Although the camera comes with a highly sophisticated 77-segment AE sensor for metering, the metering can be hugely unpredictable, especially in high contrast situations.
In Conclusion
The SD15 produces extraordinarily sharp and detailed images, and its "back-to-basics" approach will be refreshing for any photographer who isn't interested in a load of bells and whistles and extras. However, the sheer bulk and crudeness of the camera is off-putting. The lack of sensible controls doesn't help either.
It's certainly not a camera for the novice photographer, but, if you're a film user looking to switch over to digital, this may well be an interesting choice.