I noticed that sometimes my 5DMIII takes two shots as opposed to one (in single shooting mode). I'm not saying this happens all the times; in fact, it happened two or three times (top) in one month ...
I used to be able to see both aperture f-number and shutter speed, and change both values on Av mode on my Canon 550 DSLR. Now, I can only see the aperture f-number and not the shutter speed on the ...
What do the T and v stand for? Public-domain image from Wikipedia.