What is 200mm f2 8 on micro four thirds in full frame?

200mm on Micro Four Thirds gives the view of 400mm on full frame. For the same depth of field, f/2.8 there behaves like about f/5.6 on full frame. Exposure doesn't change: f/2.8 gives the same brightness on any sensor.

The same view on every common format:

• Medium format (44 x 33): 506mm at about f/7.1 for the same depth of field
• Full frame: 400mm at about f/5.6 for the same depth of field
• APS-C: 267mm at about f/3.7 for the same depth of field
• APS-C (Canon): 250mm at about f/3.5 for the same depth of field
• Micro Four Thirds (yours): 200mm at about f/2.8 for the same depth of field
• 1-inch: 148mm at about f/2.1 for the same depth of field
• 1/1.3-inch: 111mm at about f/1.6 for the same depth of field
• 1/1.7-inch: 87mm at about f/1.2 for the same depth of field
• 1/2.3-inch: 71mm at about f/1 for the same depth of field

Crop factors are by the sensor diagonal, rounded as they're usually quoted; a format with a different shape (4:3 against 3:2) frames a little differently across the width. More in the focal length converter.

Computed from the sensor sizes, not written by a model.