You asked
What is 19mm f2 8 on micro four thirds in full frame?
19mm on Micro Four Thirds gives the view of 38mm 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): 48mm at about f/7.1 for the same depth of field
- Full frame: 38mm at about f/5.6 for the same depth of field
- APS-C: 25mm at about f/3.7 for the same depth of field
- APS-C (Canon): 24mm at about f/3.5 for the same depth of field
- Micro Four Thirds (yours): 19mm at about f/2.8 for the same depth of field
- 1-inch: 14mm at about f/2.1 for the same depth of field
- 1/1.3-inch: 11mm at about f/1.6 for the same depth of field
- 1/1.7-inch: 8.3mm at about f/1.2 for the same depth of field
- 1/2.3-inch: 6.8mm 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.