On this page, I collect information about the Ricoh GXR A12-28 camera unit, also called lensor or module.
The A12-28 camera unit contains an APS-C size sensor module (CMOS, total pixels: approx. 12.9 million, effective pixels approx. 12.3 million) with a focal length of 18.3 mm that is equivalent to 28 mm. It corresponds to a modest wide angle lens for a (D)SLR. It has a focus ring, which regrettably is not purely manual, but "by wire." There are also no depth of field indicators on the lens body, but depth of field information is provided in the viewfinder or on the LCD screen when focusing manually. Also note that A12 camera units do not incorporate a vibration correction (also called anti-shake correction).
Photo: GR Lens A12-28 mm equiv. F2.5
Finally, I should add that this camera unit is able to capture videos in HD 720p format.
Photos: Body with A12-28 camera unit attached - lens protruded on the left
Photos: Top view of body with A12-28 camera unit attached - "off" (left) and "on" (right)
I received my A12-28 unit in mid November at a time when it was not really available in Germany (or Europe). All in all, this unit is similar to the A12-50 in many aspects, so that I need not repeat myself. Some people find autofocus even faster than on the A12-50. Regrettably, I also found that it sometimes misses its target...
With a focal length 28 mm equiv. this camera unit is a modest wide angle lens, and its usefulness depends on your personal shooting habits. Some people find it more useful than the A12-50 (street photographers, certain landscapes), others, like me, find the A12-50 more versatile. One poster regretted that this unit does not have a macro function. In fact, it is the first Ricoh without macro. But I find longer focal lengths more useful for macros anyway, so I can live with this omission.
Without an EVF, the GXR with A12-28 unit attached is a fairly compact package as long as it it turned off (that is, in your pocket). If you turn the camera on, the lens protrudes somewhat (see photo above).
All in all, this camera unit can, like the A12-50 unit, be regarded as a high performance unit. It has an image quality comparable to the A12-50 unit, but my sample seems to be a little bit fuzzy in the corners (maybe as the result of dropping it in summer 2011 - I still have to check that...). While many forum posters prefer a focal length of 28 mm to 50 mm, it is the opposite with me. At least, I find myself using the A12-50 unit a lot more than the A12-28.
I did a lot of test shots with the A12-28 camera unit when it was new. You can find them on this site in the "Sample Photos" section (see Links).
With its APS-C sensor, the A12-28 camera unit offers an image quality comparable to that of DSLRs - just like the preceding A12-50 unit. Like with its predecessor, image quality is hampered by visible banding in night scenes, which is caused by the CMOS sensor. However, I did not check that in detail yet.
Autofocus speed and accuracy are on par with the A12-50 after the 1.29 firmware update, some people find the A12-28 even faster. However, I have sometimes issues with focusing, particularly at night.
Which unit you prefer in the end, depends on your personal shooting habits, as I remarked already for the A12-50. I do not miss the macro mode in this unit, because I not not find macro very useful with short focal lengths (I have my A12-50 for that purpose).
All in all, the Ricoh A12-28 is a good companion to the A12-50. For street photographers it is a valid option, particularly in bad lighting conditions. Moreover, the GXR is more compact with this unit attached than with the a little bulky A12-50. The S10, however, makes the GXR even more compact and is another option for street photographers.