What is 16 28mm on canon aps c in full frame?

16-28mm on APS-C (Canon) gives the view of 26-45mm on full frame.

The same view on every common format:

• Medium format (44 x 33): 32-57mm
• Full frame: 26-45mm
• APS-C: 17-30mm
• APS-C (Canon) (yours): 16-28mm
• Micro Four Thirds: 13-22mm
• 1-inch: 9.5-17mm
• 1/1.3-inch: 7.1-12mm
• 1/1.7-inch: 5.6-9.7mm
• 1/2.3-inch: 4.6-8mm

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.