Pentax K-3 Specs, Sensor Size & Crop Factor

Q: What is the crop factor of the Pentax K-3?

The Pentax K-3 has a crop factor of 1.52× relative to 35 mm full frame (diagonal 28.4 mm vs 43.3 mm).

1.52×

Crop factor

23.7×15.7 mm

Sensor size

372 mm²

Area · 43% of full frame

24.7 MP

Resolution

3.94 µm

Pixel pitch

f/5.9

Diffraction-limited aperture

2013

Release year

Specifications#

Brand: Pentax
Model: K-3
Camera type: DSLR
Released: 2013-01-01
Lens mount: Pentax K
Sensor size: 23.7 × 15.7 mm (APS-C)
Crop factor: 1.52×
Resolution: 24.7 MP (6,016 × 4,000 px)
ISO range: 100 – 51,200
Continuous shooting: 8.3 fps
Weight: 800 g (28.2 oz)
Sensor: APS-C 23.7 × 15.7 mm CMOS sensor
Viewfinder: Eye-level pentaprism, 100% coverage, 0.95× magnification
Metering: 86,000-pixel RGB metering sensor with Real-Time Scene Analysis System
Exposure modes: Green (fully automatic), program, aperture priority, shutter priority, sensitivity priority, aperture and shutter priority, manual, bulb, X-sync shutter speed, three User presets.
Flash: Onboard pop-up flash; hot shoe for P-TTL flash units with high-speed sync support; PC socket for studio flashes; 1/180 s X-sync speed
Battery: D-LI90 lithium-ion rechargeable battery
Dimensions: 131×97×73 mm
Lens: Interchangeable Pentax KAF3 and KAF2 mount compatible with Pentax auto-aperture lenses; older lenses supported in stop-down metering mode
Made in: Philippines
Drive: Up to 8.3 fps for 60 JPEG or 23 raw images

Specifications merged from Wikipedia, Wikidata, Lensfun and openMVG. Spot an error? Tell us.

Sensor size compared#

The Pentax K-3 sensor (highlighted) drawn to scale against common formats. Its area is 43% of a full-frame sensor, which collects about 1.2 stops less total light at the same exposure.

Focal length equivalents & field of view#

Multiply any focal length by 1.52 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	112.0°	88.9°	121.3°
10 mm	15 mm	99.7°	76.3°	109.7°
12 mm	18 mm	89.3°	66.4°	99.7°
14 mm	21 mm	80.5°	58.6°	90.9°
16 mm	24 mm	73.0°	52.3°	83.2°
18 mm	27 mm	66.7°	47.1°	76.6°
20 mm	30 mm	61.3°	42.9°	70.8°
24 mm	37 mm	52.6°	36.2°	61.3°
28 mm	43 mm	45.9°	31.3°	53.8°
35 mm	53 mm	37.4°	25.3°	44.2°
40 mm	61 mm	33.0°	22.2°	39.1°
50 mm	76 mm	26.7°	17.8°	31.7°
56 mm	85 mm	23.9°	16.0°	28.5°
70 mm	107 mm	19.2°	12.8°	23.0°
85 mm	129 mm	15.9°	10.6°	19.0°
100 mm	152 mm	13.5°	9.0°	16.2°
135 mm	205 mm	10.0°	6.7°	12.0°
200 mm	304 mm	6.8°	4.5°	8.1°
300 mm	457 mm	4.5°	3.0°	5.4°
400 mm	609 mm	3.4°	2.2°	4.1°
600 mm	913 mm	2.3°	1.5°	2.7°
800 mm	1218 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 19.7 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	8.9 cm	36.9 cm	1.65 m	4.58 m	48.7 m	∞	5.54 m
14 mm	f/2.8	13.9 cm	60.2 cm	3.26 m	17.2 m	∞	∞	3.57 m
14 mm	f/4	20.3 cm	94.1 cm	8.83 m	∞	∞	∞	2.50 m
14 mm	f/8	46.2 cm	4.28 m	∞	∞	∞	∞	1.26 m
28 mm	f/1.8	2.1 cm	8.8 cm	36.0 cm	82.2 cm	2.37 m	11.3 m	22.1 m
28 mm	f/2.8	3.3 cm	13.7 cm	56.6 cm	1.31 m	3.99 m	27.7 m	14.2 m
28 mm	f/4	4.8 cm	19.7 cm	82.6 cm	1.97 m	6.67 m	∞	9.97 m
28 mm	f/8	9.6 cm	40.7 cm	1.88 m	5.58 m	∞	∞	5.00 m
48 mm	f/1.8	0.7 cm	2.9 cm	12.0 cm	27.3 cm	76.7 cm	3.14 m	65.0 m
48 mm	f/2.8	1.1 cm	4.6 cm	18.7 cm	42.6 cm	1.20 m	5.06 m	41.8 m
48 mm	f/4	1.5 cm	6.5 cm	26.8 cm	61.2 cm	1.74 m	7.71 m	29.3 m
48 mm	f/8	3.1 cm	13.1 cm	54.4 cm	1.26 m	3.83 m	25.4 m	14.7 m
78 mm	f/1.8	0.2 cm	1.1 cm	4.5 cm	10.2 cm	28.7 cm	1.16 m	172 m
78 mm	f/2.8	0.4 cm	1.7 cm	7.0 cm	15.9 cm	44.7 cm	1.81 m	110 m
78 mm	f/4	0.5 cm	2.4 cm	10.0 cm	22.8 cm	64.0 cm	2.61 m	77.2 m
78 mm	f/8	1.1 cm	4.8 cm	20.0 cm	45.7 cm	1.30 m	5.51 m	38.7 m

Equivalent aperture#

Exposure is identical at the same f-number on any format; equivalence only describes depth of field and total light.

Aperture on this camera	Full-frame equivalent (depth of field)	Hyperfocal at 28 mm
f/1.2	f/1.8	33.2 m
f/1.4	f/2.1	28.4 m
f/1.8	f/2.7	22.1 m
f/2	f/3.0	19.9 m
f/2.8	f/4.3	14.2 m
f/4	f/6.1	9.97 m
f/5.6	f/8.5	7.13 m
f/8	f/12.2	5.00 m

Diffraction & pixel pitch#

With 3.94 µm pixels, diffraction starts to soften pixel-level detail around f/5.9. For maximum sharpness keep landscapes between f/3.2 and f/6; stopping down further trades detail for depth of field.

Aperture	Airy disk diameter	Spread over	At 100% view
f/2.8	3.8 µm	1.0 px	sharp
f/4	5.4 µm	1.4 px	sharp
f/5.6	7.5 µm	1.9 px	sharp
f/8	10.7 µm	2.7 px	slight softening
f/11	14.8 µm	3.7 px	visibly soft
f/16	21.5 µm	5.5 px	visibly soft
f/22	29.5 µm	7.5 px	visibly soft

Maximum print sizes#

At 24.7 MP the Pentax K-3 produces 6,016 × 4,000 pixel images. See the 24 megapixel guide or the print size calculator.

Resolution	Typical use	Inches	Centimetres
300 DPI	Photo-lab quality	20.1 × 13.3 in	51 × 34 cm
240 DPI	Fine-art inkjet	25.1 × 16.7 in	64 × 42 cm
200 DPI	Wall print	30.1 × 20.0 in	76 × 51 cm
150 DPI	Poster, viewed from 1 m+	40.1 × 26.7 in	102 × 68 cm

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.

Focal length	500 rule	NPF f/1.8	NPF f/2.8	NPF f/4
9 mm (14 mm eq.)	36.5 s	20.1 s	24.0 s	28.7 s
13 mm (20 mm eq.)	25.3 s	13.9 s	16.6 s	19.9 s
16 mm (24 mm eq.)	20.5 s	11.3 s	13.5 s	16.1 s
23 mm (35 mm eq.)	14.3 s	7.9 s	9.4 s	11.2 s
33 mm (50 mm eq.)	10.0 s	5.5 s	6.6 s	7.8 s

Open the NPF / 500 rule calculator →

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
66 mm	1/100 s	1/13 s	0.3 s
131 mm	1/200 s	1/25 s	1/6 s

Lenses for the Pentax K-3#

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.

Frequently asked questions#

What is the crop factor of the Pentax K-3?

The Pentax K-3 has a crop factor of 1.52× relative to 35 mm full frame (diagonal 28.4 mm vs 43.3 mm).

What size is the Pentax K-3 sensor?

23.7 × 15.7 mm (APS-C), an area of 372 mm² — 43% of full frame.

Is the Pentax K-3 full frame?

No — its sensor is APS-C, which is 2.3× smaller in area than full frame.

How many megapixels does the Pentax K-3 have?

24.7 megapixels (6,016 × 4,000 pixels), enough for a 20 × 13 inch print at 300 DPI.

What lens mount does the Pentax K-3 use?

The Pentax K-3 uses the Pentax K (flange distance 45.46 mm).

How long can I expose the night sky with the Pentax K-3?

With a 13 mm lens (20 mm equivalent) the 500 rule gives 25 s and the stricter NPF rule at f/2.8 gives 17 s.

Sources & licences#

Last updated October 03, 2026 · How we calculate · Sources