Specifications#
- Brand
- Pentax
- Model
- Optio 33LF
- Camera type
- Compact
- Sensor size
- 5.3 × 3.9 mm (1/2.5" sensor)
- Crop factor
- 6.57×
Specifications merged from Wikidata, Lensfun and openMVG. Spot an error? Tell us.
Sensor size compared#
Focal length equivalents & field of view#
Multiply any focal length by 6.57 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 | 26 mm | 67.1° | 52.0° | 78.9° |
| 4.5 mm | 30 mm | 61.1° | 46.9° | 72.4° |
| 5 mm | 33 mm | 55.9° | 42.6° | 66.8° |
| 6 mm | 39 mm | 47.7° | 36.0° | 57.5° |
| 8 mm | 53 mm | 36.7° | 27.4° | 44.8° |
| 10 mm | 66 mm | 29.7° | 22.1° | 36.5° |
| 12 mm | 79 mm | 25.0° | 18.5° | 30.7° |
| 15 mm | 99 mm | 20.1° | 14.8° | 24.8° |
| 20 mm | 131 mm | 15.1° | 11.1° | 18.7° |
| 25 mm | 164 mm | 12.1° | 8.9° | 15.0° |
| 30 mm | 197 mm | 10.1° | 7.4° | 12.5° |
| 40 mm | 263 mm | 7.6° | 5.6° | 9.4° |
| 50 mm | 328 mm | 6.1° | 4.5° | 7.5° |
| 70 mm | 460 mm | 4.3° | 3.2° | 5.4° |
| 100 mm | 657 mm | 3.0° | 2.2° | 3.8° |
| 150 mm | 985 mm | 2.0° | 1.5° | 2.5° |
Depth of field table#
Total depth of field at each subject distance, using a circle of confusion of 4.6 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 | 30.8 cm | 1.68 m | ∞ | ∞ | ∞ | ∞ | 1.76 m |
| 4 mm | f/2.8 | 47.0 cm | 4.35 m | ∞ | ∞ | ∞ | ∞ | 1.25 m |
| 4 mm | f/4 | 83.4 cm | ∞ | ∞ | ∞ | ∞ | ∞ | 88.0 cm |
| 4 mm | f/8 | ∞ | ∞ | ∞ | ∞ | ∞ | ∞ | 44.2 cm |
| 7 mm | f/2 | 9.3 cm | 38.3 cm | 1.72 m | 4.86 m | 69.9 m | ∞ | 5.37 m |
| 7 mm | f/2.8 | 13.1 cm | 55.6 cm | 2.85 m | 12.0 m | ∞ | ∞ | 3.84 m |
| 7 mm | f/4 | 19.0 cm | 85.8 cm | 6.64 m | ∞ | ∞ | ∞ | 2.69 m |
| 7 mm | f/8 | 42.5 cm | 3.28 m | ∞ | ∞ | ∞ | ∞ | 1.35 m |
| 12 mm | f/2 | 3.1 cm | 12.6 cm | 51.3 cm | 1.18 m | 3.52 m | 21.2 m | 15.8 m |
| 12 mm | f/2.8 | 4.3 cm | 17.7 cm | 72.9 cm | 1.71 m | 5.51 m | 83.3 m | 11.3 m |
| 12 mm | f/4 | 6.2 cm | 25.5 cm | 1.08 m | 2.66 m | 10.6 m | ∞ | 7.89 m |
| 12 mm | f/8 | 12.6 cm | 53.5 cm | 2.71 m | 10.7 m | ∞ | ∞ | 3.95 m |
| 20 mm | f/2 | 1.1 cm | 4.5 cm | 18.1 cm | 41.0 cm | 1.15 m | 4.81 m | 43.8 m |
| 20 mm | f/2.8 | 1.5 cm | 6.3 cm | 25.4 cm | 57.7 cm | 1.63 m | 7.11 m | 31.3 m |
| 20 mm | f/4 | 2.2 cm | 9.0 cm | 36.5 cm | 83.2 cm | 2.40 m | 11.5 m | 21.9 m |
| 20 mm | f/8 | 4.4 cm | 18.1 cm | 74.8 cm | 1.76 m | 5.74 m | 108 m | 11.0 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 (26 mm eq.) | 19.0 s |
| 5 mm (33 mm eq.) | 15.2 s |
| 6 mm (39 mm eq.) | 12.7 s |
| 7 mm (46 mm eq.) | 10.9 s |
| 8 mm (53 mm eq.) | 9.5 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 |
|---|---|---|---|
| 4 mm | 1/25 s | 0.3 s | 1.3 s |
| 8 mm | 1/50 s | 1/6 s | 0.6 s |
| 15 mm | 1/100 s | 1/13 s | 0.3 s |
| 30 mm | 1/200 s | 1/25 s | 1/6 s |
Lens#
The Pentax Optio 33LF 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 × 6.57.
Similar cameras#
Other 1/2.5" cameras from around the same time.
Frequently asked questions#
What is the crop factor of the Pentax Optio 33LF?
The Pentax Optio 33LF has a crop factor of 6.57× relative to 35 mm full frame (diagonal 6.6 mm vs 43.3 mm).
What size is the Pentax Optio 33LF sensor?
5.3 × 3.9 mm (1/2.5"), an area of 21 mm² — 2% of full frame.
Is the Pentax Optio 33LF full frame?
No — its sensor is 1/2.5", which is 41.7× smaller in area than full frame.
How long can I expose the night sky with the Pentax Optio 33LF?
With a 5 mm lens (33 mm equivalent) the 500 rule gives 15 s.
Sources & licences#
- Wikidata Q140489800 — CC0
- Lensfun camera database — CC BY-SA 3.0
- openMVG sensor width database — MPL-2.0
Last updated October 03, 2026 · How we calculate · Sources