Did you find a fix for this. My Rebel XS has exactly the same issue which was caused by a good hard drop from 5 feet. I can hear something "flop" when tipping the camera slightly up which causes the diopter to be focused.
They offer one, Canon +1 Diopter E, which is supposed to fit "most EOS Cameras." Check with your owner's manual, or with Canon, to be certain. Even if you do order it from B&H, and it doesn't fit, they get excellent reviews for their return policy. Personally, I'm in the same boat. The adjustment range, -3 to +1, on my 6D doesn't do it for me.
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The shockingly simple answer is by adjusting the camera’s diopter. If the word diopter doesn’t ring a bell then keep reading and if it does keep reading nonetheless. Adjusting the diopter of your viewfinder is one of the smallest yet important things you can do to ensure that your scene is focused properly. Fine-Tuning What The Camera Sees

Buy Blackmagic Design Pocket Cinema Camera Pro EVF for 6K Pro featuring EVF for Pocket Cinema Camera 6K Pro, Glass Diopter with -4 to +4 Adjustment, Built-In Status & Digital Focus Chart, 70° Swivel, 1280 x 960 Resolution, Micro OLED, 24-Bit RGB, 16.7M Colors, Set of 4 Eyecups for Right & Left Eyes.
As I recall (and this can be a little confusing), the OM body eyepiece lenses have a built in power of -0.5. So, if you need a minus 2, and you buy an Olympus diopter, diopter lens is really a -1.5, -1.5 plus eyepiece -0.5 equals -2.0. If you go to an optometrist and get him to make a -2 for you, you'll put it on the camera and it becomes -2.5. wzA6E. 484 410 395 456 77 333 429 145 351

diopter adjustment on canon camera