Perhaps. I don't know why it overs aturated the yellows. I took some more sunset shots, and things look normal, however. I didn't use shutter lock up. I also didn't see any increase in sharpness either. Although from what I've read, the most troublesome shutter speeds for vibration due to the shutter atre between 1/4 sec and 1/60th. When I shoot sunsets, that is usually not a problem.
If they are made of metal, then why do manuals advise not opening the mirror into the sun for an extended time?
The yellows become oversaturated because of the IR sensitivity of the Canon sensor. It is a general characteristic, not specifically in relation to sunset images. It will also happen when shooting sunlit flowers (or late afternoon where flowers may exhibit a kind of afterglow, which apparently is IR or heat radiation). Even more interesting may be butterflies for example, which sometimes have spots on their wings which completely clip in digital capture.
The manual advises against prolonged sun exposure because the lens may be concentrating the light to a single spot as a magnifying glass may do, which will completely toast your sensor. Idem for the lens itself, because there is always the nodal point within the lens where the rays converge to a single point.
However, for a normal exposure, where the sun expands over a reasonable area, there shouldn't be any problem with the sensor or the lens.
