[Gracana]

> The concentration involved is no different than setting a leaf on fire with a magnifying glass on a regular day.

That's what they're saying. Zooming in on the sun vs the sun happening to be in-frame.

[xsmasher]

Are you saying zooming in on the sun makes damage more likely?

Wouldn't zooming in spread the sun's energy across more of the sensor? Same energy, larger area = less intensity.

[grahn]

The irradiance is determined by the aperture, which is measured relative to the focal length. So with e.g. f/2 you get the same heating of a given area of the sensor regardless of the focal length (i.e. "zoom").

Put differently, longer lenses typically also have bigger absolute apertures, collecting incident light from a larger cross-section. This compensates for the fact that a given solid angle of incident light is spread over a larger area of the sensor.