The SD1 features a new body, significantly evolved from the design of the SD14 and 15. The external shell is constructed of magnesium alloy, and feels solid in your hand with no creaks or flexing. The result is a very conventional camera (in the best possible sense) with twin control dials and direct access buttons for all of the key photographic settings, making it quick and easy to operate with the camera to your eye.
The buttons that were clustered on the top-right-hand shoulder on previous Sigma models are spread out more sensibly across the top of the SD1. While they're not necessarily perfectly placed from a comfort perspective (especially the ISO button), they're sufficiently well separated so you can find the right one by touch alone. The side-effect of this rearrangement of buttons is the loss of that endangered species, the top-plate LCD, which is replaced by a comprehensive status display on the rear screen.
The built-in pop-up flash has a guide number of 11 (ISO100/m), and can provide coverage for lenses as wide as 17mm. It lifts far enough up to avoid shadowing with the DC 17-50mm F2.8 EX OS HSM lens (which is probably the SD1's most natural companion).
The flash can also wirelessly control Sigma's EF DG Super series external units.
The hotshoe has contacts for fully dedicated operation with Sigma's own flash units, such as the EF-610 DG Super.
There's also a standard PC sync socket for studio flash use (see below).
The SD1 includes an LED AF illuminator lamp in the recess between the lens mount and the handgrip. Its position means that it only works with the center AF point. It can also be blocked by larger lenses. It can be disabled in the camera's menus.
This lamp is also used for red-eye reduction with the built-in flash.
The SD1 is compatible with Sigma's RS-31 wireless remote control; the receiver is placed on the front of the camera at the lower right corner. Sadly there's no receiver on the back for when you're shooting from behind the camera.
The tripod mount is centered with the lens, and there's plenty of space around it for a quick release plate.
The SD1 Merrill wears its full name on the baseplate sticker, where the original model (shown here) just says 'SD1'.
The compact flash card slot lives behind a conventionally-positioned spring door at the back of the handgrip. The compartment is sealed against dust and moisture ingress.
With no HD output to worry about, the SD1's connectors are fairly minimalist - there's a flash sync port, DC power input, USB/AV connector, and socket for the CR-21 cable release.
Oddly, the latter has no half-press position for focusing before releasing the shutter. Coincidentally, the camera will also work with the easier-to-find Canon RS-60E3 release, or its third-party clones.
The SD1 uses the familiar BP-21 battery, with 12Wh capacity; however Sigma appears not to have published a CIPA battery life rating.
The battery itself sits behind a latch-operated door with environmental seals around the edges. The door can be removed for the addition of the PG-31 vertical grip.
The SD1 uses Sigma's own SA mount - so you can only use Sigma lenses. A wide range is available, but only a very few are weather-sealed The SD1 has a standard APS-C 'crop factor' of 1.5x (the company's older cameras were 1.7x).
As with previous Sigma DSLRs, the camera features a protective anti-dust screen at the front of the lens mount.