Okay, two very different questions, but no need for two threads.
Very simple - my 5D keeps saving files as .jpeg and not .jpg - there are some compatibility problems i have with that, they need to be .jpg - its done it before, in fact its very strange in how it does things. it sometimes does .jpg, but most often does .jpeg - particularly as of late. also - sometimes instead of saying PICT0123 it will say _ICT0123... whats up with that?
and second question - noise reduction - is it allright to keep it on at all times? or should i only use it when shooting 800 and up? how effective is this noise reduction really, anyway?