What is 55 210mm on aps c in full frame?

55-210mm on APS-C gives the view of 82-315mm on full frame.

The same view on every common format:

• Medium format (44 x 33): 104-399mm
• Full frame: 82-315mm
• APS-C (yours): 55-210mm
• APS-C (Canon): 52-197mm
• Micro Four Thirds: 41-158mm
• 1-inch: 31-117mm
• 1/1.3-inch: 23-87mm
• 1/1.7-inch: 18-68mm
• 1/2.3-inch: 15-56mm

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.