Sensor format

Four Thirds / Micro Four Thirds

A 4:3 sensor with a 2× crop factor. Lenses and bodies are compact; telephoto reach doubles, depth of field is one-stop-and-a-third deeper than APS-C at the same framing.

17.3×13 mm

Dimensions

2.00×

Crop factor

225 mm²

Area (26% of FF)

-1.9

Stops of light vs full frame

4:3

Aspect ratio

15.0 µm

Circle of confusion

About Four Thirds / Micro Four Thirds#

A 4:3 sensor with a 2× crop factor. Lenses and bodies are compact; telephoto reach doubles, depth of field is one-stop-and-a-third deeper than APS-C at the same framing.

Typical cameras: OM System OM-1, Panasonic GH6, G9 II.

Compared to other formats#

Lens needed for the same framing#

Full-frame focal length	Equivalent on Four Thirds / Micro Four Thirds	Horizontal angle
14 mm	7.0 mm	102.0°
24 mm	12.0 mm	71.6°
35 mm	17.5 mm	52.6°
50 mm	25.0 mm	38.2°
85 mm	42.5 mm	23.0°
135 mm	67.5 mm	14.6°
200 mm	100.0 mm	9.9°

Equivalent aperture for depth of field#

On Four Thirds / Micro Four Thirds	Full-frame equivalent
f/1.4	f/2.8
f/2	f/4.0
f/2.8	f/5.6
f/4	f/8.0
f/5.6	f/11.2
f/8	f/16.0

Cameras with a Four Thirds / Micro Four Thirds sensor#

110 cameras in our database.

Depth-of-field tables for this format#

24 mm f/1.8 24 mm f/2.8 24 mm f/8 35 mm f/1.8 35 mm f/2.8 35 mm f/8 50 mm f/1.8 50 mm f/2.8 50 mm f/8 85 mm f/1.8 85 mm f/2.8 85 mm f/8

Frequently asked questions#

What is the crop factor of Four Thirds / Micro Four Thirds?

2.00× (diagonal 21.6 mm vs 43.3 mm for full frame).

How big is a Four Thirds / Micro Four Thirds sensor?

17.3 × 13 mm, an area of 225 mm².

Is Four Thirds / Micro Four Thirds good in low light?

At the same exposure it gathers 1.9 stops less total light than full frame, so expect roughly that much more visible noise at equal print size. Modern processing narrows but doesn't erase the gap.

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