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

8-16mm on APS-C gives the view of 12-24mm on full frame.

The same view on every common format:

• Medium format (44 x 33): 15-30mm
• Full frame: 12-24mm
• APS-C (yours): 8-16mm
• APS-C (Canon): 7.5-15mm
• Micro Four Thirds: 6-12mm
• 1-inch: 4.4-8.9mm
• 1/1.3-inch: 3.3-6.7mm
• 1/1.7-inch: 2.6-5.2mm
• 1/2.3-inch: 2.1-4.3mm

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.