What is 200 800mm on canon aps c in full frame?

200-800mm on APS-C (Canon) gives the view of 320-1280mm on full frame.

The same view on every common format:

• Medium format (44 x 33): 405-1620mm
• Full frame: 320-1280mm
• APS-C: 213-853mm
• APS-C (Canon) (yours): 200-800mm
• Micro Four Thirds: 160-640mm
• 1-inch: 119-474mm
• 1/1.3-inch: 89-356mm
• 1/1.7-inch: 70-278mm
• 1/2.3-inch: 57-229mm

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.