Specifications#
- Brand
- Samsung
- Model
- GX-20
- Camera type
- DSLR
- Lens mount
- Pentax K
- Sensor size
- 23.4 × 15.6 mm (APS-C)
- Crop factor
- 1.54×
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 1.54 to get the full-frame field of view. Angles are for a rectilinear lens focused at infinity.
| Lens on this camera | Full-frame equivalent | Horizontal | Vertical | Diagonal |
|---|---|---|---|---|
| 8 mm | 12 mm | 111.3° | 88.6° | 120.7° |
| 10 mm | 15 mm | 99.0° | 76.0° | 109.2° |
| 12 mm | 18 mm | 88.5° | 66.1° | 99.1° |
| 14 mm | 22 mm | 79.8° | 58.3° | 90.3° |
| 16 mm | 25 mm | 72.4° | 52.0° | 82.6° |
| 18 mm | 28 mm | 66.0° | 46.9° | 76.0° |
| 20 mm | 31 mm | 60.7° | 42.7° | 70.2° |
| 24 mm | 37 mm | 52.0° | 36.1° | 60.8° |
| 28 mm | 43 mm | 45.4° | 31.2° | 53.3° |
| 35 mm | 54 mm | 37.0° | 25.2° | 43.8° |
| 40 mm | 62 mm | 32.6° | 22.1° | 38.8° |
| 50 mm | 77 mm | 26.3° | 17.8° | 31.4° |
| 56 mm | 86 mm | 23.6° | 15.9° | 28.2° |
| 70 mm | 108 mm | 19.0° | 12.7° | 22.7° |
| 85 mm | 131 mm | 15.7° | 10.5° | 18.8° |
| 100 mm | 154 mm | 13.3° | 8.9° | 16.0° |
| 135 mm | 208 mm | 9.9° | 6.6° | 11.9° |
| 200 mm | 308 mm | 6.7° | 4.5° | 8.0° |
| 300 mm | 461 mm | 4.5° | 3.0° | 5.4° |
| 400 mm | 615 mm | 3.4° | 2.2° | 4.0° |
| 600 mm | 923 mm | 2.2° | 1.5° | 2.7° |
| 800 mm | 1230 mm | 1.7° | 1.1° | 2.0° |
Depth of field table#
Total depth of field at each subject distance, using a circle of confusion of 19.5 µm (the 0.030 mm full-frame standard scaled by the crop factor). Detailed tables: 24 mm f/1.8, 24 mm f/2.8, 35 mm f/1.8, 35 mm f/2.8, 50 mm f/1.8, 50 mm f/2.8.
| Focal | Aperture | 50.0 cm | 1.00 m | 2.00 m | 3.00 m | 5.00 m | 10.0 m | Hyperfocal |
|---|---|---|---|---|---|---|---|---|
| 14 mm | f/1.8 | 8.8 cm | 36.5 cm | 1.63 m | 4.50 m | 44.2 m | ∞ | 5.60 m |
| 14 mm | f/2.8 | 13.8 cm | 59.4 cm | 3.19 m | 16.2 m | ∞ | ∞ | 3.60 m |
| 14 mm | f/4 | 20.1 cm | 92.8 cm | 8.44 m | ∞ | ∞ | ∞ | 2.53 m |
| 14 mm | f/8 | 45.5 cm | 4.09 m | ∞ | ∞ | ∞ | ∞ | 1.27 m |
| 28 mm | f/1.8 | 2.1 cm | 8.7 cm | 35.6 cm | 81.3 cm | 2.34 m | 11.2 m | 22.4 m |
| 28 mm | f/2.8 | 3.3 cm | 13.6 cm | 56.0 cm | 1.30 m | 3.94 m | 26.9 m | 14.4 m |
| 28 mm | f/4 | 4.7 cm | 19.5 cm | 81.7 cm | 1.94 m | 6.55 m | 1.3 km | 10.1 m |
| 28 mm | f/8 | 9.5 cm | 40.2 cm | 1.86 m | 5.46 m | 484 m | ∞ | 5.05 m |
| 48 mm | f/1.8 | 0.7 cm | 2.9 cm | 11.9 cm | 27.0 cm | 75.9 cm | 3.10 m | 65.7 m |
| 48 mm | f/2.8 | 1.1 cm | 4.5 cm | 18.6 cm | 42.2 cm | 1.19 m | 5.00 m | 42.2 m |
| 48 mm | f/4 | 1.5 cm | 6.5 cm | 26.6 cm | 60.6 cm | 1.73 m | 7.60 m | 29.6 m |
| 48 mm | f/8 | 3.1 cm | 13.0 cm | 53.8 cm | 1.25 m | 3.78 m | 24.7 m | 14.8 m |
| 78 mm | f/1.8 | 0.2 cm | 1.1 cm | 4.4 cm | 10.1 cm | 28.4 cm | 1.15 m | 173 m |
| 78 mm | f/2.8 | 0.4 cm | 1.7 cm | 6.9 cm | 15.8 cm | 44.3 cm | 1.80 m | 111 m |
| 78 mm | f/4 | 0.5 cm | 2.4 cm | 9.9 cm | 22.5 cm | 63.4 cm | 2.59 m | 78.0 m |
| 78 mm | f/8 | 1.1 cm | 4.7 cm | 19.8 cm | 45.2 cm | 1.28 m | 5.44 m | 39.1 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 |
|---|---|
| 9 mm (14 mm eq.) | 36.1 s |
| 13 mm (20 mm eq.) | 25.0 s |
| 16 mm (25 mm eq.) | 20.3 s |
| 23 mm (35 mm eq.) | 14.1 s |
| 33 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 |
|---|---|---|---|
| 16 mm | 1/25 s | 0.3 s | 1.3 s |
| 33 mm | 1/50 s | 1/6 s | 0.6 s |
| 65 mm | 1/100 s | 1/13 s | 0.3 s |
| 130 mm | 1/200 s | 1/25 s | 1/6 s |
Lenses for the Samsung GX-20#
Native Pentax K lenses in our database (170 total). Also adaptable: T-mount (T2), M42 screw mount, Deckel (DKL), Tamron Adaptall, M39 / LTM (Leica thread).
- Samyang 8mm f/3.5 Fish-Eye CS 8 mm
- Samyang 10mm f/2.8 ED AS NCS CS 10 mm
- Laowa 12mm f/2.8 Zero-D 12 mm
- Samyang 14mm f/2.8 AE ED AS IF UMC 14 mm
- Laowa 15mm F/4 Wide Angle Macro 15 mm
- Samyang 16mm f/2.0 ED AS UMC CS 16 mm
- Samyang 20mm f/1.8 ED AS UMC 20 mm
- Samyang 24mm f/1.4 ED AS IF UMC 24 mm
- Samyang T-S 24mm f/3.5 ED AS UMC 24 mm
- Laowa 60mm f/2.8 2X Ultra-Macro 60 mm
- Samyang 85mm f/1.4 IF UMC Aspherical 85 mm
- Samyang 135mm f/2 ED UMC 135 mm
- Sigma 4.5mm f/2.8 EX DC HSM circular fisheye 4.5 mm
- Sigma 8-16mm f/4.5-5.6 DC HSM 8–16 mm
- Pentax smc Pentax-DA Fish-Eye 10-17mm f/3.5-4.5 ED IF 10–17 mm
- Sigma 10-20mm f/3.5 EX DC HSM 10–20 mm
- Sigma 10-20mm f/4-5.6 EX DC 10–20 mm
- Sigma 10mm f/2.8 EX DC Fisheye HSM 10 mm
- Tamron SP AF 10-24mm f/3.5-4.5 Di II LD Aspherical (IF) 10–24 mm
- Pentax HD Pentax-DA* 11-18mm f/2.8 ED DC AW 11–18 mm
- Tamron SP AF 11-18mm f/4.5-5.6 Di-II LD Aspherical (IF) 11–18 mm
- Pentax smc Pentax-DA 12-24mm f/4 ED AL IF 12–24 mm
- Sigma 12-24mm F4.5-5.6 II DG HSM 12–24 mm
- Sigma 12-24mm f/4.5-5.6 EX DG Aspherical HSM 12–24 mm
- Pentax smc PENTAX-DA 14mm F2.8 ED[IF] 14 mm
- Sigma 14mm f/2.8 EX 14 mm
- Sigma 14mm f/2.8 EX Aspherical HSM 14 mm
- Sigma 14mm f/3.5 EX 14 mm
- Pentax HD Pentax-D FA 15-30mm f/2.8 ED SDM WR 15–30 mm
- Pentax smc Pentax-DA 15mm f/4 ED AL Limited 15 mm
- Sigma 15-30mm f/3.5-4.5 EX DG Aspherical 15–30 mm
- Sigma 15mm f/2.8 EX DG Diagonal Fisheye 15 mm
- Pentax HD Pentax DA* 16-50mm f/2.8 ED PLM AW 16–50 mm
- Pentax HD Pentax-DA 16-85mm f/3.5-5.6 ED DC WR 16–85 mm
- Pentax smc Pentax-DA 16-45mm f/4 ED AL 16–45 mm
- Pentax smc Pentax-DA* 16-50mm f/2.8 ED AL IF SDM 16–50 mm
Similar cameras#
Other APS-C cameras from around the same time.
- Nikon D40 2006
- Pentax K110D 2006
- Nikon D60 2008
- Nikon D7000 2010
- Pentax K-5 2010
- Sony Alpha 65 2011
- Nikon D7100 2013
- Pentax K-3 2013
- Sony Alpha 58 2013
- Sony Alpha 77 II 2014
- Ricoh Pentax K-3 II 2015
- Nikon D5600 2016
Frequently asked questions#
What is the crop factor of the Samsung GX-20?
The Samsung GX-20 has a crop factor of 1.54× relative to 35 mm full frame (diagonal 28.1 mm vs 43.3 mm).
What size is the Samsung GX-20 sensor?
23.4 × 15.6 mm (APS-C), an area of 366 mm² — 42% of full frame.
Is the Samsung GX-20 full frame?
No — its sensor is APS-C, which is 2.4× smaller in area than full frame.
What lens mount does the Samsung GX-20 use?
The Samsung GX-20 uses the Pentax K (flange distance 45.46 mm).
How long can I expose the night sky with the Samsung GX-20?
With a 13 mm lens (20 mm equivalent) the 500 rule gives 25 s.
Sources & licences#
- Wikidata Q4048989 — 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