Ricoh GR Optics

Fixed 18.3mm lens
Excellent far-field performance from the 18.3mm f/2.8 fixed lens.

The Ricoh GR is equipped with a fixed 18.3mm f/2.8 lens, with a 35mm-equivalent focal length of about 28mm. Construction consists of 7 elements in 5 groups including two double-sided aspherics, with a 9-bladed diaphragm providing an aperture range of f/2.8 to f/16. There's a built-in 2 EV neutral density filter as well.

Sharpness and contrast are very good at f/8 across the frame, and chromatic aberration is quite low (see below for more on that). Performance in the corners looks to be very good (but a little difficult to evaluate in this image), with just a hint coma distortion. There is some corner shading ("vignetting"), but it's fairly minor. See below for comments on macro mode, geometric distortion, performance wide open, chromatic aberration, etc.

The Ricoh GR does not offer digital "zoom," but it does offer a 35mm-equivalent crop mode that produces 10.3-megapixel images with no upsampling.

Macro
A larger-than-average minimum coverage area, with good performance. Flash exposure is offset at closest range, but throttled down well.

The Ricoh GR captures a fairly large minimum area measuring 4.44 x 2.94 inches (113 x 75 millimeters) in Macro mode. Sharpness is quite good over most of the frame at f/8, with only minor softening in the corners. (Most lenses have some softening in the corners at macro distances, but the GR's lens does better than most.) The flash throttled down well, but coverage is not very even, illuminating the top left portion of the frame better than the bottom right, so plan on using external lighting for macro shots at closest distance.

Geometric Distortion
Very low geometric distortion.

The Ricoh GR's lens produces only about 0.1 percent of complex (wavy) barrel distortion, which is very low, especially for a wide-angle lens. Uncorrected RAW files exhibit the same low distortion, which is a pleasant surprise. This is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide-angle) or inward (like a pincushion -- usually at telephoto).

Chromatic Aberration and Corner Sharpness
Very low levels of C.A. (and the camera suppresses what little there is). The lens produces slightly soft corners when wide open, but corner performance is excellent when stopped-down.

Chromatic Aberration. Chromatic aberration in the corners of in-camera JPEGs is fairly low when wide open, exacerbated somewhat by softening, while the center of the image shows almost no CA. Stopping-down to f/5.6 or f/8 reduces the number of colored pixels, but they are slightly more distinct. Still, C.A. is very low in JPEGs.

Corner Softness. Wide open at f/2.8, the GR's lens exhibits mild blurring in right hand side corners, though left corners are sharper. The blurring doesn't extend too far into the frame, though, and the center is quite sharp. When stopped down to f/5.6 or f/8, all four corners exhibit excellent sharpness; almost as sharp as the center.

Corner Shading. The Ricoh GR's lens shows moderate corner shading ("vignetting"), and it's present even when stopped-down to f/8.

Lens Corrections

The Ricoh GR applies chromatic aberration suppression as well as some corner shading compensation, as geometric distortion appears to be the same in uncorrected RAW files.

Chromatic Aberration Suppression

As you can see, lateral chromatic aberration is a little higher and brighter in uncorrected RAW files, however it's still quite low.


Overall, an excellent lens that's sharp from edge-to-edge when stopped down from maximum aperture, with low distortion, minimal chromatic aberration but moderate vignetting.

Coverage
Excellent accuracy from the LCD monitor.

The Ricoh GR's LCD monitor shows essentially 100% coverage in record mode. This is excellent performance, though not a surprise given its image is derived from the imaging sensor.