Well, just wondering. If you take pictures of the sun/sunset/etc... where sun hits the sensor and see it through the viewfinder, do you actually bother on protecting your eye? Just did a quick google search and found this article.
Bottom line, NEVER LOOK DIRECTLY AT THE SUN!
Considering the multipliers... i.e. lens focal lengths, cropped sensors, % of viewfinder, mirrors, and minus the UV filtre... it is still bad. Even if it is sunset and comparing this on watching some solar eclipse, experts always say to use some special glasses to protect your eyes!