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Surface damage mostly depends on the power density, not on total power, so it depends mostly on the aperture, not on the focal length. This makes longer focal lengths safer to point at the sun because they are slower lenses. They are also safer if you don't explicitly point them at the sun because they are less likely to catch the sun in the smaller field of view.

Burned shutter cloths on Leica M series cameras with wide angle lenses is a real problem that can happen simply if you leave the camera without a lens cap lying on a table. This is less of a problem on most other cameras, as they use metal shutter curtains.