What is 8 14mm on aps c in full frame?

8-14mm on APS-C gives the view of 12-21mm on full frame.

The same view on every common format:

• Medium format (44 x 33): 15-27mm
• Full frame: 12-21mm
• APS-C (yours): 8-14mm
• APS-C (Canon): 7.5-13mm
• Micro Four Thirds: 6-10mm
• 1-inch: 4.4-7.8mm
• 1/1.3-inch: 3.3-5.8mm
• 1/1.7-inch: 2.6-4.6mm
• 1/2.3-inch: 2.1-3.8mm

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.