As unusual designs in digital photography go, this one takes the prize for 2010 so far. The Ricoh GXR isn't so much a camera with interchangeable lenses, as a camera platform with interchangeable cameras.
The body itself contains no image sensor; only the LCD monitor and associated electronics, battery and SD card slot. To turn it into something that will take photos, you need to attach one of the lens units.
Each unit is a self-contained, sealed box incorporating not only a lens, but also the iris mechanism, shutter and image sensor - essentially, a complete camera.
In theory, this gives unique flexibility, but it makes the lens units enormously expensive. There are currently two on offer: the S10 sports the same type of small, optically stabilised 1/1.7in sensor you find in digital compacts, plus a 24-70mm zoom lens. Buying it separately from a GXR body will set you back around $500.
The A12, meanwhile, features a high-quality fixed-focal-length 50mm f/2.5 lens, plus a large APS-C sensor. That gives you digital SLR-level image quality, but you'll pay $869 for the privilege of buying one separately.
Incidentally, the GXR body doesn't have an optical viewfinder, only a 3in LCD panel. If you want the optional LCD hot-shoe-mounted viewfinder, it will set you back an outrageous $275.
Ricoh claims a couple of upsides to a sealed lens and sensor unit. First is the ability to precisely tailor the lens and sensor assembly, which supposedly allows a better design of low-pass optical filter to be used, reducing colour noise. Second is the fact that you'll never need to worry about dust contamination from lens changes.
We can't argue with that, but there are weaknesses too. All lenses in the GXR system use contrast-detect autofocus, and this is slow compared to the phase-detect system used by a DSLR. To combat the sluggishness, there's a feature called full-press snap.
With this activated, pressing the shutter button all the way without pausing at the halfway mark takes a quick shot at a predefined, fixed focus point. However, there's still a clearly perceptible shutter lag.
The quality of the A12 50mm macro lens and APS-C sensor combination is very high. The maximum image-size ratio is 1:2, which means the image projected onto the sensor is half the actual size rather than the 1:1 ratio strictly required for it to qualify as a true macro lens, but nonetheless you can get very close.
With the aperture set to f/2.5, the depth of field for macro shots is extremely shallow, giving you plenty of scope for creative photography. There was no hint of chromatic aberration in any of our test shots with the A12 lens, images were pin-sharp and noise was well controlled too, even up to the maximum ISO 3200 sensitivity.
Results from the small sensor S10 were less impressive. Noise was far too high to be usable over ISO 800, although chromatic aberrations were again well controlled. The results essentially look just like those from a compact camera, with the standard small-sensor problem of limited dynamic range tending to clip the highlights.
The system is at least easy to use, with a well-balanced combination of dedicated controls along with a simple method of directly changing settings through on-screen menus.
A few sums, however, reveal the nub of the problem. The cheapest combination of GXR plus both lenses will currently cost you $1899. For that you could buy a Canon Ixus 120 IS compact, an Olympus PEN E-P1 with both 14-42mm and 17mm lenses plus optical viewfinder, and have $200 left over to put towards a new high-end lens for your DSLR.
Granted, the absolute level of image quality of the GXR with the A12 lens will pip the E-P1 at the post, but only in situations where a fixed 50mm lens will give you the shot you want.
With the A12 lens unit fitted the GXR is certainly a capable, if very expensive, fixed-focal-length digital camera. With the S10 fitted, it's merely an exceptionally overpriced compact. Plus, where a DSLR system gives you dozens of lenses to choose from, only two are currently available for the Ricoh.
It's an interesting development, and one that generated keen interest around the office. But the GXR concept is a solution to a problem that doesn't appear to exist. If you're desperate to be different, you might consider it.
For most, though, it's too expensive, and offers no compelling benefits over competitors at half the price. And with no word on when the range might expand, its theoretical flexibility doesn't give you much real flexibility at all.