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#

Full frame (35 mm)APS-CFour Thirds / Micro Four Thirds1" (one-inch) sensor1/2.3" sensor

Lens needed for the same framing#

Full-frame focal lengthEquivalent on Four Thirds / Micro Four ThirdsHorizontal angle
14 mm7.0 mm102.0°
24 mm12.0 mm71.6°
35 mm17.5 mm52.6°
50 mm25.0 mm38.2°
85 mm42.5 mm23.0°
135 mm67.5 mm14.6°
200 mm100.0 mm9.9°

Equivalent aperture for depth of field#

On Four Thirds / Micro Four ThirdsFull-frame equivalent
f/1.4f/2.8
f/2f/4.0
f/2.8f/5.6
f/4f/8.0
f/5.6f/11.2
f/8f/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/1.824 mm f/2.824 mm f/835 mm f/1.835 mm f/2.835 mm f/850 mm f/1.850 mm f/2.850 mm f/885 mm f/1.885 mm f/2.885 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

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