What is 9mm f8 on micro four thirds in full frame?

9mm on Micro Four Thirds gives the view of 18mm on full frame. For the same depth of field, f/8 there behaves like about f/16 on full frame. Exposure doesn't change: f/8 gives the same brightness on any sensor.

The same view on every common format:

• Medium format (44 x 33): 23mm at about f/20.3 for the same depth of field
• Full frame: 18mm at about f/16 for the same depth of field
• APS-C: 12mm at about f/10.7 for the same depth of field
• APS-C (Canon): 11mm at about f/10 for the same depth of field
• Micro Four Thirds (yours): 9mm at about f/8 for the same depth of field
• 1-inch: 6.7mm at about f/5.9 for the same depth of field
• 1/1.3-inch: 5mm at about f/4.4 for the same depth of field
• 1/1.7-inch: 3.9mm at about f/3.5 for the same depth of field
• 1/2.3-inch: 3.2mm at about f/2.9 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.