Hmm.. can viewing the viewfinder on the 450D with spectacles on be tiring? Havent actually used an SLR for a prolonged period, perhaps someone cares to explain?
It can be if the person is short-sighted and needs to stare at small distant objects for extended periods of time. I have no problems with looking through viewfinder for prolonged periods.
My eyes however get tired easily when I need to stare at the LCD screen during post-processing. :bsmilie: