Ricoh GR III Camera Review

Sharpness

Sharpness, or the ability to resolve small details, is an important measure of the performance of a lens. Sharp images let the viewer concentrate on the composition, color and light. On the other hand, soft images (except when looking that way on purpose) distract the viewer and decrease the perceived quality of the picture.

Testing the Ricoh GR III is different to testing a lens, as the sensor and lens are linked together. Testing will still be done similarly to our lens tests.

There are many ways to evaluate sharpness. Some are quantitative, such as the number of lines per millimeter that can be resolved, while others are comparative, such as using a standardized scene to pit lenses against one another. The latter is the favored method at Pentax Forums.

Test Setup, Star Chart

In order to evaluate sharpness, we photograph a standard test chart (or "star chart") that can be used to compare lenses to one another. The general rule is that the distance from the lens to the test chart must be 100 times the focal length of the lens. For our lens, this means a distance of 2.8 meters.

The test is not designed to show how good a lens can be. Quite the contrary: it is a stress test designed to put the lens at its limits to show where it falls short. The test shows the apertures where the lens performs best, and makes it possible to compare with another lens.

Our test has the star chart put successively at the center, edge and corner of the field of view of the lens, testing all apertures each time.

New Pentax DSLR bodies, as well as the GR III, include the ability to disable anti-aliasing, a very useful feature allowing higher resolutions to be reached. However, the nature of our sharpness test and the pattern of the test chart mean that, with anti-aliasing totally disabled, moiré is likely to appear. In order to strike the best balance between sharpness and moiré reduction, the anti-aliasing simulators were activated and set at the "Low" setting.

Test Results at 28mm on APS-C

The following images showcase the results at all apertures on APS-C. Focusing was performed by using focus peaking in live view. It was corrected after each lens movement. You can click on images to see full resolution crops.

Center
Edge
Corner
F2.8
APS-C Center F2.8 APS-C Edge F2.8 APS-C Corner F2.8
F4
APS-C Center F4 APS-C Edge F4 APS-C Corner F4
F5.6
APS-C Center F5.6 APS-C Edge F5.6 APS-C Corner F5.6
F8
APS-C Center F8 APS-C Edge F8 APS-C Corner F8
F11
APS-C Center F11 APS-C Edge F11 APS-C Corner F11
F16
APS-C Center F16 APS-C Edge F16 APS-C Corner F16

Center sharpness is already very good wide open and edges are close. Corners lag a bit at F2.8, but not by much. At F4, the center reaches close to its peak performances, and the corners improve. Until F8, the center remains a bit sharper but edges and corners even out and offer high sharpness. F11 shows some diffraction, and F16 is visibly softer.

Considering that this lens will often be used wide open, the high resolution and high uniformity are extremely positive. This is a lens that can be used with confidence and little variation between F2.8 and F8. These results are impressive.

Real-life Test

Test charts never tell the whole story. The following images illustrate the performance of the lens with a real-life test subject with a lot of detail. We used a close distance to differentiate with the star chart tests, which are performed at a significant range. We moved our camera to place the subject in the center, the edge and then corner, refocusing between each shot.

Test Results at 28mm

The following images showcase the results at all apertures on full frame. Focusing was performed using spot focus, and confirmed via focus peaking. It was corrected after each lens movement. You can click on images to see full resolution crops.

Center
Edge
Corner
F2.8
FF Center F2.8 FF Edge F2.8 FF Corner F2.8
F4
FF Center F4 FF Edge F4 FF Corner F4
F5.6
FF Center F5.6 FF Edge F5.6 FF Corner F5.6
F8
FF Center F8 FF Edge F8 FF Corner F8
F11
FF Center F11 FF Edge F11 FF Corner F11
F16
FF Center F16 FF Edge F16 FF Corner F16

The results observed with the test chart are repeated here. The level of sharpness is high at all apertures below F11, and the differences are small between the center, edges and corners.

Summary

The GR III offers high resolution figures to its users. It is perfectly usable across the frame even wide open. The center always remains sharper than the edges and corners, but not by much between F4 and F8. It would be hard to ask for more from this lens.


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