I have taken thousands of pictures on my seven-year-old Canon T2i with no issues. Then, out of the blue, I am finding that when the camera is in manual, T, AV, P or A-DEP mode, I have to press the shutter release button twice for the camera to take a picture. I've checked all the settings; nothing corrects it. It doesn't do this in any of the auto modes. Is it possible I've accidentally changed some bizarre setting that I can't find? I don't know.
And it's not as though the shutter is open the whole time between clicks. It makes a sound, and you can tell it's not operating correctly. also, the viewfinder is black while your press the shutter release the second time.
Thanks in advance for your suggestions.