Specifications#
- Brand
- Ricoh
- Model
- GR Digital III
- Also known as
- GR DIGITAL 3, Ricoh GR Digital 3
- Camera type
- Compact
- Released
- 2009-01-01
- Sensor size
- 7.5 × 5.7 mm (1/1.7" sensor)
- Crop factor
- 4.60×
Specifications merged from Wikidata and openMVG. Spot an error? Tell us.
Sensor size compared#
Focal length equivalents & field of view#
Multiply any focal length by 4.60 to get the full-frame field of view. For fixed-lens cameras use the real focal length printed on the lens (e.g. “6.1–18.3 mm”), not the 35 mm equivalent.
| Lens on this camera | Full-frame equivalent | Horizontal | Vertical | Diagonal |
|---|---|---|---|---|
| 4 mm | 18 mm | 86.5° | 70.5° | 99.3° |
| 4.5 mm | 21 mm | 79.8° | 64.2° | 92.6° |
| 5 mm | 23 mm | 74.0° | 58.9° | 86.5° |
| 6 mm | 28 mm | 64.2° | 50.4° | 76.2° |
| 8 mm | 37 mm | 50.4° | 38.9° | 60.9° |
| 10 mm | 46 mm | 41.3° | 31.5° | 50.4° |
| 12 mm | 55 mm | 34.8° | 26.5° | 42.8° |
| 15 mm | 69 mm | 28.2° | 21.3° | 34.8° |
| 20 mm | 92 mm | 21.3° | 16.1° | 26.5° |
| 25 mm | 115 mm | 17.1° | 12.9° | 21.3° |
| 30 mm | 138 mm | 14.3° | 10.8° | 17.8° |
| 40 mm | 184 mm | 10.8° | 8.1° | 13.4° |
| 50 mm | 230 mm | 8.6° | 6.5° | 10.8° |
| 70 mm | 322 mm | 6.2° | 4.6° | 7.7° |
| 100 mm | 460 mm | 4.3° | 3.2° | 5.4° |
| 150 mm | 689 mm | 2.9° | 2.2° | 3.6° |
Depth of field table#
Total depth of field at each subject distance, using a circle of confusion of 6.5 µm (the 0.030 mm full-frame standard scaled by the crop factor).
| Focal | Aperture | 50.0 cm | 1.00 m | 2.00 m | 3.00 m | 5.00 m | 10.0 m | Hyperfocal |
|---|---|---|---|---|---|---|---|---|
| 4 mm | f/2 | 48.4 cm | 4.79 m | ∞ | ∞ | ∞ | ∞ | 1.23 m |
| 4 mm | f/2.8 | 83.4 cm | ∞ | ∞ | ∞ | ∞ | ∞ | 87.9 cm |
| 4 mm | f/4 | 2.35 m | ∞ | ∞ | ∞ | ∞ | ∞ | 61.7 cm |
| 4 mm | f/8 | ∞ | ∞ | ∞ | ∞ | ∞ | ∞ | 31.0 cm |
| 9 mm | f/2 | 8.0 cm | 32.8 cm | 1.43 m | 3.77 m | 22.8 m | ∞ | 6.21 m |
| 9 mm | f/2.8 | 11.2 cm | 47.1 cm | 2.25 m | 7.44 m | ∞ | ∞ | 4.44 m |
| 9 mm | f/4 | 16.2 cm | 71.1 cm | 4.37 m | 82.1 m | ∞ | ∞ | 3.11 m |
| 9 mm | f/8 | 35.2 cm | 2.16 m | ∞ | ∞ | ∞ | ∞ | 1.56 m |
| 15 mm | f/2 | 2.8 cm | 11.5 cm | 46.7 cm | 1.07 m | 3.16 m | 17.4 m | 17.2 m |
| 15 mm | f/2.8 | 3.9 cm | 16.1 cm | 66.2 cm | 1.55 m | 4.84 m | 47.4 m | 12.3 m |
| 15 mm | f/4 | 5.6 cm | 23.2 cm | 97.3 cm | 2.36 m | 8.69 m | ∞ | 8.63 m |
| 15 mm | f/8 | 11.4 cm | 48.2 cm | 2.34 m | 7.99 m | ∞ | ∞ | 4.32 m |
| 25 mm | f/2 | 1.0 cm | 4.1 cm | 16.5 cm | 37.4 cm | 1.05 m | 4.36 m | 47.9 m |
| 25 mm | f/2.8 | 1.4 cm | 5.7 cm | 23.2 cm | 52.6 cm | 1.49 m | 6.38 m | 34.2 m |
| 25 mm | f/4 | 2.0 cm | 8.2 cm | 33.2 cm | 75.7 cm | 2.17 m | 10.1 m | 24.0 m |
| 25 mm | f/8 | 4.0 cm | 16.4 cm | 67.9 cm | 1.59 m | 5.02 m | 54.6 m | 12.0 m |
Equivalent aperture#
Exposure is identical at the same f-number on any format; equivalence only describes depth of field and total light.
Night-sky exposure limits#
Longest exposure before stars trail. The NPF rule accounts for pixel pitch and is stricter than the classic 500 rule — use it for pin-sharp stars on high-resolution sensors. (NPF needs a known resolution and is omitted here.)
| Focal length | 500 rule |
|---|---|
| 4 mm (18 mm eq.) | 27.2 s |
| 5 mm (23 mm eq.) | 21.8 s |
| 6 mm (28 mm eq.) | 18.1 s |
| 8 mm (37 mm eq.) | 13.6 s |
| 11 mm (51 mm eq.) | 9.9 s |
Handheld shutter speed guide#
The reciprocal rule uses the equivalent focal length. High-resolution sensors may need one stop faster than this for pixel-sharp results.
| Focal length | No stabilisation (1/equiv. focal) | With 3-stop IS | With 5-stop IBIS |
|---|---|---|---|
| 5 mm | 1/25 s | 0.3 s | 1.3 s |
| 11 mm | 1/50 s | 1/6 s | 0.6 s |
| 22 mm | 1/100 s | 1/13 s | 0.3 s |
| 44 mm | 1/200 s | 1/25 s | 1/6 s |
Lens#
The Ricoh GR Digital III has a built-in, non-interchangeable lens. Use the real focal length of that lens with the tables above; its full-frame equivalent is that number × 4.60.
Similar cameras#
Other 1/1.7" cameras from around the same time.
Frequently asked questions#
What is the crop factor of the Ricoh GR Digital III?
The Ricoh GR Digital III has a crop factor of 4.60× relative to 35 mm full frame (diagonal 9.4 mm vs 43.3 mm).
What size is the Ricoh GR Digital III sensor?
7.5 × 5.7 mm (1/1.7"), an area of 43 mm² — 5% of full frame.
Is the Ricoh GR Digital III full frame?
No — its sensor is 1/1.7", which is 20.3× smaller in area than full frame.
How long can I expose the night sky with the Ricoh GR Digital III?
With a 5 mm lens (23 mm equivalent) the 500 rule gives 22 s.
Sources & licences#
- Wikidata Q20889209 — CC0
- openMVG sensor width database — MPL-2.0
Last updated October 03, 2026 · How we calculate · Sources