Mirrorless

Pentax Q-S1

The Pentax Q-S1 is a mirrorless with a 1/1.7" sensor measuring 7.4 × 5.6 mm and 12 megapixels. Its crop factor is 4.65×, so a 50 mm lens frames like 233 mm on full frame. Every number below is calculated for this exact sensor.

1/1.7"4.65× crop12 MPPentax Q
4.65×
Crop factor
7.4×5.6 mm
Sensor size
42 mm²
Area · 5% of full frame
12 MP
Resolution
1.86 µm
Pixel pitch
f/2.8
Diffraction-limited aperture

Specifications#

Brand
Pentax
Model
Q-S1
Camera type
Mirrorless
Lens mount
Pentax Q
Sensor size
7.4 × 5.6 mm (1/1.7" sensor)
Crop factor
4.65×
Resolution
12 MP (4,000 × 3,000 px)
Fastest shutter
1/2,000 s
Continuous shooting
5 fps
Weight
203 g (7.2 oz)
Sensor type
BSI-CMOS, stabilized
Dimensions
105 x 58 x 34mm (4.13 x 2.28 x 1.34 inches)
Drive
5 frames per second

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

Sensor size compared#

1" (one-inch) sensorPentax Q-S11/2.3" sensor
The Pentax Q-S1 sensor (highlighted) drawn to scale against common formats. Its area is 5% of a full-frame sensor, which collects about 4.4 stops less total light at the same exposure.

Focal length equivalents & field of view#

Multiply any focal length by 4.65 to get the full-frame field of view. Angles are for a rectilinear lens focused at infinity.

Lens on this cameraFull-frame equivalentHorizontalVerticalDiagonal
4 mm19 mm85.8°69.8°98.6°
4.5 mm21 mm79.2°63.6°91.9°
5 mm23 mm73.3°58.3°85.8°
6 mm28 mm63.6°49.9°75.6°
8 mm37 mm49.9°38.5°60.3°
10 mm47 mm40.8°31.2°49.9°
12 mm56 mm34.4°26.2°42.4°
15 mm70 mm27.9°21.1°34.4°
20 mm93 mm21.1°15.9°26.2°
25 mm116 mm16.9°12.7°21.1°
30 mm140 mm14.1°10.6°17.6°
40 mm186 mm10.6°8.0°13.3°
50 mm233 mm8.5°6.4°10.6°
70 mm326 mm6.1°4.6°7.6°
100 mm465 mm4.3°3.2°5.3°
150 mm698 mm2.8°2.1°3.6°

Depth of field table#

Total depth of field at each subject distance, using a circle of confusion of 6.4 µm (the 0.030 mm full-frame standard scaled by the crop factor).

FocalAperture50.0 cm1.00 m2.00 m3.00 m5.00 m10.0 mHyperfocal
4 mmf/247.6 cm4.52 m∞∞∞∞1.24 m
4 mmf/2.881.5 cm∞∞∞∞∞89.0 cm
4 mmf/42.22 m∞∞∞∞∞62.4 cm
4 mmf/8∞∞∞∞∞∞31.4 cm
9 mmf/27.9 cm32.4 cm1.41 m3.70 m21.6 m∞6.29 m
9 mmf/2.811.1 cm46.4 cm2.21 m7.20 m∞∞4.50 m
9 mmf/416.0 cm70.1 cm4.24 m61.6 m∞∞3.15 m
9 mmf/834.7 cm2.10 m∞∞∞∞1.58 m
15 mmf/22.8 cm11.3 cm46.1 cm1.06 m3.11 m17.0 m17.5 m
15 mmf/2.83.9 cm15.9 cm65.4 cm1.52 m4.76 m44.8 m12.5 m
15 mmf/45.6 cm22.9 cm96.0 cm2.33 m8.49 m∞8.74 m
15 mmf/811.3 cm47.6 cm2.30 m7.72 m∞∞4.38 m
25 mmf/21.0 cm4.0 cm16.3 cm37.0 cm1.04 m4.30 m48.5 m
25 mmf/2.81.4 cm5.6 cm22.9 cm52.0 cm1.47 m6.29 m34.6 m
25 mmf/42.0 cm8.1 cm32.8 cm74.8 cm2.14 m9.91 m24.3 m
25 mmf/83.9 cm16.2 cm67.0 cm1.57 m4.94 m51.1 m12.1 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 cameraFull-frame equivalent (depth of field)Hyperfocal at 9 mm
f/1.2f/5.610.5 m
f/1.4f/6.58.98 m
f/1.8f/8.46.99 m
f/2f/9.36.29 m
f/2.8f/13.04.50 m
f/4f/18.63.15 m
f/5.6f/26.12.25 m
f/8f/37.21.58 m

Diffraction & pixel pitch#

With 1.86 µm pixels, diffraction starts to soften pixel-level detail around f/2.8. For maximum sharpness keep landscapes between f/2.8 and f/3; stopping down further trades detail for depth of field.

ApertureAiry disk diameterSpread overAt 100% view
f/2.83.8 µm2.0 pxslight softening
f/45.4 µm2.9 pxslight softening
f/5.67.5 µm4.0 pxvisibly soft
f/810.7 µm5.8 pxvisibly soft
f/1114.8 µm7.9 pxvisibly soft
f/1621.5 µm11.5 pxvisibly soft
f/2229.5 µm15.9 pxvisibly soft

Maximum print sizes#

At 12 MP the Pentax Q-S1 produces 4,000 × 3,000 pixel images. See the 12 megapixel guide or the print size calculator.

ResolutionTypical useInchesCentimetres
300 DPIPhoto-lab quality13.3 × 10.0 in34 × 25 cm
240 DPIFine-art inkjet16.7 × 12.5 in42 × 32 cm
200 DPIWall print20.0 × 15.0 in51 × 38 cm
150 DPIPoster, viewed from 1 m+26.7 × 20.0 in68 × 51 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 length500 ruleNPF f/1.8NPF f/2.8NPF f/4
4 mm (19 mm eq.)26.9 s29.7 s38.5 s49.0 s
5 mm (23 mm eq.)21.5 s23.8 s30.8 s39.2 s
6 mm (28 mm eq.)17.9 s19.8 s25.6 s32.6 s
8 mm (37 mm eq.)13.4 s14.9 s19.2 s24.5 s
11 mm (51 mm eq.)9.8 s10.8 s14.0 s17.8 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 lengthNo stabilisation (1/equiv. focal)With 3-stop ISWith 5-stop IBIS
5 mm1/25 s0.3 s1.3 s
11 mm1/50 s1/6 s0.6 s
21 mm1/100 s1/13 s0.3 s
43 mm1/200 s1/25 s1/6 s

Frequently asked questions#

What is the crop factor of the Pentax Q-S1?

The Pentax Q-S1 has a crop factor of 4.65× relative to 35 mm full frame (diagonal 9.3 mm vs 43.3 mm).

What size is the Pentax Q-S1 sensor?

7.4 × 5.6 mm (1/1.7"), an area of 42 mm² — 5% of full frame.

Is the Pentax Q-S1 full frame?

No — its sensor is 1/1.7", which is 20.8× smaller in area than full frame.

How many megapixels does the Pentax Q-S1 have?

12 megapixels (4,000 × 3,000 pixels), enough for a 13 × 10 inch print at 300 DPI.

What lens mount does the Pentax Q-S1 use?

The Pentax Q-S1 uses the Pentax Q (flange distance 9.20 mm).

How long can I expose the night sky with the Pentax Q-S1?

With a 5 mm lens (23 mm equivalent) the 500 rule gives 21 s and the stricter NPF rule at f/2.8 gives 31 s.

Sources & licences#

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