Body & Design

Physically, the QX100 looks like it's all just lens, but there's a shutter and zoom toggle on the side and a sizable sensor buried within and a lithium-ion battery behind all of that. A detachable plastic mount ships with the unit, sliding on to the back with a bayonet-style twist. A pair of clamping arms unfold and one is spring-loaded, stretching to attach to the edges of a smartphone.

Opposite the card slot is a small battery life indicator and a hole for a wrist strap. On the bottom of the unit is a tripod mount, expanding the QX100's capabilities as a remote camera. This flattened portion of the round lens barrel also allows the QX100 to rest on a flat surface.

The QX100 is powered on and off by way of a small rectangular button on the top of the lens housing. Powered on, the lens extends from the housing, increasing the overall length of the unit by about half. Powered off, the lens is fully concealed within the QX100.

Ergonomics

It's a strange thing to hold what seems like only the lens of a compact camera. That said, it doesn't feel bad, just unusual. Holding it in the right hand, my thumb rests over the shutter and zoom toggle. Using it this way you can shoot 'from the hip;' half-pressing the shutter will give you an AF confirmation beep and images are stored only to the card. Coupling the QX100 to a smartphone gives you an LCD - it's getting it clamped to your phone that can be tricky.

Flipping up the clamps on the back of the QX100 is a job that's best done with two hands. The top clamp moves up and down, effectively spreading the two tabs apart so a phone can be placed between them. Releasing the top clamp will allow it to slide into place bracing the phone. This can be slightly cumbersome, especially if you're out and about when you attempt this as you're juggling two very expensive pieces of equipment. With a little practice it's easy to master, but the first few times I mounted the QX100 to the Galaxy S4 and iPhone 5, it felt a little awkward and still makes me slightly nervous.

Underneath the blue Zeiss logo is the QX100's MicroSD card slot (it will also accept Memory Stick Micro) and a microUSB port that's used to charge the battery. The RX100 II will record images to a phone and memory card simultaneously if both are available. Without connection to a phone, images will be saved to the card, and vice versa. The port cover concealing the card slot feels quite flimsy.
The QX100 bears a function ring, a feature of the RX100 II, though it controls fewer functions in the QX100. In manual focus mode it adjusts focus (without any focus peaking or magnification help) and in all other shooting modes controls zoom.
The QX100's clamps sit flush against the back of the unit at rest; they're pulled out at a 90 degree angle in order to mount the QX100 to a phone. The top clamp is sprung and can get higher or lower to accommodate bigger or smaller smartphones. At its widest the clamps span a little more than 3.0 inches - just barely wide enough to clamp to a Samsung Galaxy Note II.
The QX100's battery compartment and clamping bayonet mount all add depth to an already bulky device, making it deeper than the RX100 II.
On the bottom of the QX100 is a tripod mount, built into a flattened portion of the device's cylindrical housing.
The QX100 is powered by a replaceable lithium-ion battery enclosed in the rear of the device. The battery is charged in-camera by way of a micro USB port and included cable/wall adapter.

The clamps are padded with grippy rubber teeth, helping to keep a better hold on your mobile device. The mount sits flush against the back of a smartphone, and the clamps keep a relatively good grip on the phone, but it still feels ever-so-slightly unsteady. This was most noticeable when just holding the phone and putting faith in the clamps to keep the lens in place. Keeping the left hand under the lens, with shutter and zoom easily reached by thumb, felt much more secure.

Most smartphones have very slim edges, and the QX100 is many times thicker and heavier. The clamping mechanism seems to be built just fine, but it's likely the strange balancing act between the mismatched devices that makes it feel a little awkward. The clamps can be skipped entirely if you'd rather not place it on your phone or you're operating the QX100 from a tablet; a mobile device will maintain a connection to the QX100 as far as the Wi-Fi connection allows, which in our testing was at least 30 feet.