Leica was able to squeeze a DSLR-worthy, APS-C size sensor into a handsome and compact camera body with the 12.2-megapixel X1.

Leica's been on quite a roll lately thanks to a pair of extremely well received product releases: the 18.5-megapixel, full-frame M9 rangefinder camera (reviewed in November 2009 PDN), and the 37.5-megapixel S2 DSLR/medium-format hybrid camera (reviewed here last month). I liked both cameras quite a bit and was looking forward to trying out Leica's 12.2-megapixel X1 which fits a DSLR-sized sensor into a compact camera body. If Leica could live up to the promise of the M9 and S2, I couldn't wait to see what it had in store with the X1.

Small cameras with big sensors were one of the hottest innovations last year (we named it the "Technology of the Year" in our annual Gear of the Year round-up) and while some models weren't quite ready for prime time, there was potential. The biggest issue has been the glacial speed of these big-sensored compact cameras which are slower to focus than digital SLRs. (The one exception has been the Panasonic Lumix GF1 which is also reviewed in this issue.)

Leica's X1 varies from the other cameras that have come so far mainly because its sensor is significantly larger. Where the Olympus EP-1 and EP-2; and Panasonic GF1, use Micro Four Thirds sensors, the X1 houses an APS-C sized CMOS chip which is the same size as what's in most entry-level DSLRs. (The Sigma DP-1 and DP-2 use X3 Foveon chips which are sized between Micro Four Thirds and APS-C sensors.)

Unlike the Micro Four Thirds models which use interchangeable lenses, the X1 has an attached lens with a fixed, 24mm focal length (35mm equivalent) and maximum aperture of f/2.8. The lens is similar to what was in the Leica D-Lux 4, featuring eight lens elements in six different groups

Got all that? Yes, it's confusing. Suffice it to say that expectations have been high for Leica's X1, with some photographers hoping the company had created the ultimate pocket camera.

I'm disappointed to report to you that it hasn't.

Yes, image quality from this little camera is near the best I've seen for a compact especially in low light at high ISOs. That big (23.6 x 15.7mm) chip in the X1—which mercifully is restricted to just 12-megapixel cameras—captures a lot of light even under extremely dim conditions and noise at ISO 800 and 1600 was surprisingly low.

However, using this handsome and expensive ($2,000) little camera is not a pleasant experience. In fact, it's an unmitigated slog that makes you wonder how much user testing Leica did before they released the X1. The great image quality does make you hope they might somehow fix it in the follow-up.