As previously mentioned, the SD1 is a very conventional-feeling camera. No concessions have had to be made for movie shooting or live view, as the camera does neither. There are no special processing options or gimmicks - no dynamic range expansion, no HDR, 3D mode or creative effects. Instead it just gets on with being a traditional SLR; buttons and dials offer direct access to all main shooting parameters, and you compose using the optical viewfinder only. We've not seen an SLR this simple and unashamedly pared-down since the Sony Alpha DSLR-A900 / A850 design (which itself felt slightly behind the times when it appeared back in 2008).

Overall operation and handling

The SD1 is a remarkably well-weighted camera - it feels solid but not overly-heavy. It fits securely in the hand, and remains comfortable after hours of use. Key to the SD1's excellent feel in your hand is its deep handgrip, and in particular this highly-sculpted groove for your middle finger, along with a 'channel' for your thumb on the back. Few cameras feel as secure in your grasp, even when held one-handed.

For almost all of its use the SD1 is a simple photographic tool - perhaps elegantly so, from some shooters' perspectives. Crucially, pretty well all of the main camera controls - exposure compensation, ISO, AF point selection and so on - have a dedicated external access point, while all image settings (white balance, colour mode and file type) can be accessed via either the Func or QS menus. You do have to venture into the menu to capture a custom white balance setting, but as this is the top item on the first menu page, it isn't particularly painful.

To change a setting, you have to hold down the associated button and spin whichever dial is more comfortable (or, in the case of ISO, less uncomfortable). All changes are displayed in the viewfinder, so you rarely have to take the camera away from your eye while shooting. They're also displayed on the rear LCD as you make them, which is really useful when you're working with a tripod (this behaviour can be turned off in the menu if you prefer). However the LCD only comes on when you press a button, which means it doesn't automatically display changes to the shutter speed or aperture setting; to see this you have to press the 'Func' button first.

Special mention should be made of the SD1's mirror lockup setting, which works exactly as all SLRs should. Not only is it a readily-accessible position on the drive mode dial, its behaviour can be customized: the picture can be taken either on a second press of the shutter at the user's discretion, or automatically 2 or 10 seconds after the shutter is first pressed and the mirror flips up (the latter being particularly useful when you don't have a cable release to hand). This allows for painless switching between handheld and tripod-based use, unlike some other brands we can think of (yes Canon, that means you).

The SD1's 'UP' position offers perhaps the best implementation of mirror lockup on any current SLR. Not only does it have its own position on the drive mode dial... ...you can also choose how the shutter will release after the initial press of the shutter button; either on a second press, or automatically 2 or 10 seconds later.

Specific handling issues

The SD1 isn't always the most fluid camera to use, due partially to its insistence that you must simultaneously hold down a button and spin a dial to change anything. Most other cameras now at least offer the option of pressing a button then spinning a dial, if you prefer working this way.

Probably the main disappointment, though, is that in the P, A and S exposure modes both control dials are devoted to the same parameter. This means you always have to press the exposure compensation button to move away from the metered exposure value. It would seem more logical to devote one dial to exposure compensation in these modes, or at least make it a configuration option (just like on every other two-dial SLR).

We also find the ISO button to be rather uncomfortably-positioned, requiring an unnatural contortion of your index finger diagonally backwards from the shutter button to operate it. This isn't so bad when you're simply pressing the button to check the ISO setting, but becomes distinctly awkward when you're simultaneously spinning the rear dial with your thumb, and so have to operate these two closely-spaced controls at the same time.

The ISO button is rather awkward to reach with your index finger; the exposure compensation and drive mode buttons are both much better-placed, beside and behind the shutter release respectively.

The ISO button can also become obstructed by the strap lug (to be fair, generally a minor irritation).
The auto-bracketing 'AB' position on the drive mode dial isn't in fact a drive mode at all, but simply used to set the bracketing increment, which is changed by spinning either dial.

Every other function of the camera becomes locked, and you have to move the dial back to another position to actually shoot. An AB button would surely be a more elegant solution...
...especially as there's also a completely separate menu option that sets the number of bracketed frames, and the order they're exposed. Naturally, you can't access this (or any other menu) with the drive dial set to AB.

If we were designing the camera, one press of an AEL button would bring up a single screen to change all three options.

The missing feature - Live View

It's not often we draw attention to a feature that's missing from a camera, but in the case of the SD1, we have to make an exception. We're not going to complain about the lack of a movie mode, as we suspect many stills photographers really won't mind very much, but the lack of live view looks like a real gap in the SD1's armoury.

Crucially, the SD1's unique selling point is its Foveon sensor, which is all about detail and resolution. But to get the most out of it, accurate focusing is vital. The SD1's AF is competent enough, and its viewfinder makes manual focus easier and more accurate than on most APS-C SLRs, so much of the time this isn't a huge problem. But if there's one thing we know from all our studio work, it's that when you really need to place critical focus at a particular point, the most accurate method is to use manual focus with magnified live view. You can't do this with the SD1, and this is a real disadvantage for certain types of photography (e.g. macro and still life).

For tripod-based work in general, Live View is also simply a more convenient way of composing your shots, especially when the camera is pointing at an awkward angle that demands Olympic feats of gymnastics just to place your eye to the viewfinder. Once you get used to Live View as a way of working, its omission becomes all the more glaring. It doesn't make the SD1 unusable, by any means, but it does make it less easy to use in some situations. And it's not as if the sensor can't support it, given that it's used in the DP1 Merrill and DP2 Merrill compacts.

Likewise, while the SD1 offers tethered operation from a computer with Firmware 1.4, and the Sigma Capture Pro software allows an fairly comprehensive level of camera control, the lack of live view makes this all somewhat less useful compared to cameras that can show you what the lens is actually seeing in real time. Again, it's not useless by any means, but the fact remains that competing systems simply offer more functionality.