What is 50 120mm on canon aps c in full frame?

50-120mm on APS-C (Canon) gives the view of 80-192mm on full frame.

The same view on every common format:

• Medium format (44 x 33): 101-243mm
• Full frame: 80-192mm
• APS-C: 53-128mm
• APS-C (Canon) (yours): 50-120mm
• Micro Four Thirds: 40-96mm
• 1-inch: 30-71mm
• 1/1.3-inch: 22-53mm
• 1/1.7-inch: 17-42mm
• 1/2.3-inch: 14-34mm

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.