It's not just irradiance (W/m2) that counts for retinal damage for two reasons. 1. Removal of heat is much more efficient from a small spot than from a big spot (3D versus 2D heat transfer). 2. Involuntary drift of the eye spreads out the dose if the spot size is small. (Try fixing your gaze at a spot for 10 seconds - you can't).
Some of the camera damage was in the aperure blades. Those were not in the image plane of the lens (similar to your irises). Those get quite a bit more dose if there is a big-diameter lens in front of them.
Disclosure: years ago, I reasoned that you wouldn't get blind from looking into the sun for 0.3 seconds, with binoculars, based on your irradiance argument. And tested it. Well, I didn't get permanent eye damage, but the after-image was 8x bigger in diameter than that of the sun with the naked eye and lasted for a day - rather disturbing. That was before I learned about the mechanisms of laser-induced damage.