2005GLI wrote in post #18924676
Is this something that is easily fixable?
probably depends on the definiton of "easily"... 
the Button by itself I suspect you'll have trouble getting, but you can buy parts off e-bay, for example see: https://www.ebay.com …67a7c6:g:ymMAAOxye9lSFNEz
if you're handy with a screwdriver I'd say it was a pretty simple repair. Can't quite see from your photo but if the shaft of the button has broken off it could be floating around the circuitboards underneath (or around the mirrorbox) and although of itself plastic, there should be a circlip on the end that could short stuff out so I'd be inclined to not use the camera until at least that has been found & removed.
from the parts manual, the button itself is part number CB3-2329-000, there's a spring CS5-0263-000, and the circlip "retaining ring" XD2-1100-172
some fairly old canon camera stuff, canon lenses, Manfrotto "thingy", and an M5, also an M6 that has had a 720nm filter bolted onto the sensor:
TF posting: here 