[resoluteteeth]

Dingaling is talking about the light being concentrated on certain areas of the sensor. Because the total/average brightness is low, the exposure ends up being much longer then at normal conditions, causing damage to the areas where the light is concentrated. Under normal conditions, the light will be less concentrated on certain spots, so even though there is much more light in total, the camera will choose an appropriate exposure that will prevent damage to the sensor.

[klodolph]

You'd have to be incompetent to trust autoexposure during an eclipse.