What is 8 16mm on canon aps c in full frame?

8-16mm on APS-C (Canon) gives the view of 13-26mm on full frame.

The same view on every common format:

• Medium format (44 x 33): 16-32mm
• Full frame: 13-26mm
• APS-C: 8.5-17mm
• APS-C (Canon) (yours): 8-16mm
• Micro Four Thirds: 6.4-13mm
• 1-inch: 4.7-9.5mm
• 1/1.3-inch: 3.6-7.1mm
• 1/1.7-inch: 2.8-5.6mm
• 1/2.3-inch: 2.3-4.6mm

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.