Twin-lens reflex · 1956

Mamiya C

The Mamiya C is a twin-lens reflex from 1956 that exposes a 56 × 56 mm frame on 6 × 6 cm film. Its crop factor is 0.55× — wider than full frame, so a 50 mm lens frames like 27 mm. Every number below is calculated for this exact film format.

6 × 6 cm film0.55× crop
Mamiya C camera
Photo: Ashley Pomeroy, CC BY-SA 4.0, via Wikimedia Commons
0.55×
Crop factor
56.0×56.0 mm
Image area
3136 mm²
Area · 363% of full frame
1956
Release year

Specifications#

Brand
Mamiya
Model
C
Camera type
Twin-lens reflex
Released
1956
Film format
6 × 6 cm film
Image area
56.0 × 56.0 mm (6 × 6 cm film)
Crop factor
0.55×
Sensor type
Film
Viewfinder
ground glass, waist-level
Metering
in optional viewfinders or external
Exposure modes
manual
Shutter
in lens (leaf)
Lens
Interchangeable
Predecessor
Mamiyaflex
Production
1956–1994

Specifications merged from Wikipedia. Spot an error? Tell us.

Sensor size compared#

Mamiya CMedium format 44 × 33 mmFull frame (35 mm)APS-C
The Mamiya C frame (highlighted) drawn to scale against common formats. Its area is 363% of a full-frame sensor.

Focal length equivalents & field of view#

Multiply any focal length by 0.55 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 cameraFull-frame equivalentHorizontalVerticalDiagonal
21 mm11 mm106.3°106.3°124.1°
23 mm13 mm101.2°101.2°119.7°
28 mm15 mm90.0°90.0°109.5°
32 mm17 mm82.4°82.4°102.1°
35 mm19 mm77.3°77.3°97.1°
45 mm25 mm63.8°63.8°82.7°
55 mm30 mm54.0°54.0°71.5°
63 mm34 mm47.9°47.9°64.3°
80 mm44 mm38.6°38.6°52.7°
90 mm49 mm34.6°34.6°47.5°
110 mm60 mm28.6°28.6°39.6°
120 mm66 mm26.3°26.3°36.5°
150 mm82 mm21.1°21.1°29.6°
180 mm98 mm17.7°17.7°24.8°
250 mm137 mm12.8°12.8°18.0°
350 mm191 mm9.1°9.1°12.9°

Depth of field table#

Total depth of field at each subject distance, using a circle of confusion of 54.9 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
40 mmf/1.82.8 cm11.9 cm49.2 cm1.14 m3.38 m19.8 m16.2 m
40 mmf/2.84.4 cm18.6 cm78.1 cm1.86 m6.17 m228 m10.4 m
40 mmf/46.3 cm26.8 cm1.16 m2.92 m12.7 m∞7.32 m
40 mmf/812.8 cm56.7 cm3.03 m14.4 m∞∞3.68 m
79 mmf/1.80.7 cm2.9 cm12.2 cm27.8 cm78.4 cm3.22 m63.2 m
79 mmf/2.81.0 cm4.5 cm19.0 cm43.4 cm1.23 m5.20 m40.7 m
79 mmf/41.5 cm6.5 cm27.2 cm62.3 cm1.79 m7.95 m28.5 m
79 mmf/83.0 cm13.0 cm55.1 cm1.29 m3.94 m27.3 m14.3 m
134 mmf/1.80.2 cm1.0 cm4.1 cm9.5 cm26.8 cm1.09 m182 m
134 mmf/2.80.3 cm1.5 cm6.4 cm14.7 cm41.7 cm1.70 m117 m
134 mmf/40.4 cm2.1 cm9.1 cm21.1 cm59.7 cm2.45 m81.9 m
134 mmf/80.9 cm4.2 cm18.3 cm42.3 cm1.21 m5.13 m41.0 m
221 mmf/1.80.1 cm0.3 cm1.4 cm3.4 cm9.7 cm39.6 cm494 m
221 mmf/2.80.1 cm0.5 cm2.2 cm5.2 cm15.0 cm61.6 cm318 m
221 mmf/40.1 cm0.7 cm3.2 cm7.5 cm21.5 cm88.1 cm223 m
221 mmf/80.3 cm1.4 cm6.4 cm15.0 cm43.1 cm1.77 m111 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 79 mm
f/1.2f/0.794.8 m
f/1.4f/0.881.3 m
f/1.8f/1.063.2 m
f/2f/1.156.9 m
f/2.8f/1.540.7 m
f/4f/2.228.5 m
f/5.6f/3.120.4 m
f/8f/4.414.3 m

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 length500 rule
26 mm (14 mm eq.)35.2 s
37 mm (20 mm eq.)24.7 s
44 mm (24 mm eq.)20.8 s
64 mm (35 mm eq.)14.3 s
92 mm (50 mm eq.)9.9 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
44 mm1/25 s0.3 s1.3 s
92 mm1/50 s1/6 s0.6 s
183 mm1/100 s1/13 s0.3 s
366 mm1/200 s1/25 s1/6 s

Frequently asked questions#

What is the crop factor of the Mamiya C?

The Mamiya C has a crop factor of 0.55× relative to 35 mm full frame (diagonal 79.2 mm vs 43.3 mm).

What size is the Mamiya C frame?

56.0 × 56.0 mm (6 × 6 cm film), an area of 3136 mm² — 363% of full frame.

How long can I expose the night sky with the Mamiya C?

With a 37 mm lens (20 mm equivalent) the 500 rule gives 25 s.

Sources & licences#

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