What is 300mm on micro four thirds in full frame?

300mm on Micro Four Thirds gives the view of 600mm on full frame.

The same view on every common format:

• Medium format (44 x 33): 759mm
• Full frame: 600mm
• APS-C: 400mm
• APS-C (Canon): 375mm
• Micro Four Thirds (yours): 300mm
• 1-inch: 222mm
• 1/1.3-inch: 167mm
• 1/1.7-inch: 130mm
• 1/2.3-inch: 107mm

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.