Micro Four Thirds Equivalent Focal Length

Convert a Micro Four Thirds lens to its full-frame-equivalent field of view using the format's 2× crop factor. The calculator starts with a 25mm Micro Four Thirds lens beside a 50mm full-frame lens.

Compare Micro Four Thirds with full frame

Change any focal length or crop factor to compare the resulting field of view.

Scene for comparison
1.0x 50mm
2.0x 25mm

Results

Effective Focal Length: 50.0mm
FOV: 39.6° × 27.0°
🚶Normal (travel, documentary)

Results

Effective Focal Length: 50.0mm
FOV: 39.6° × 27.0°
🏙️Wide (street, interiors)

How the conversion works

Micro Four Thirds cameras from OM System/Olympus and Panasonic use a 2× crop factor for full-frame field-of-view comparisons. Multiply the focal length on the lens by two.

For example, a 25mm Micro Four Thirds lens frames like a 50mm lens on full frame. This equivalence describes framing only; exposure settings and the lens's physical focal length do not change.

Micro Four Thirds lens focal length × 2 = full-frame-equivalent focal length

Focal length conversion table

Micro Four Thirds focal lengths and their full-frame field-of-view equivalents
Micro Four Thirds lensFull-frame-equivalent field of view
16mm 32mm
24mm 48mm
35mm 70mm
50mm 100mm
85mm 170mm
200mm 400mm

To work backward from full frame, divide by two: a 24mm full-frame view needs about a 12mm Micro Four Thirds lens.

Worked example: a 12–40mm zoom

A 12–40mm Micro Four Thirds zoom covers a field-of-view range similar to a 24–80mm lens on full frame: 12 × 2 = 24 and 40 × 2 = 80. The lens remains a 12–40mm lens, but the equivalent range makes cross-system framing easier to compare.