You hold the shutter down, in T mode, half way as if you were trying to focus i suppose, (except I use back focus normally), and in the viewfinder you will see the exposure meter, the line that tells you if you are under or over. Mine was saying under by one stop even in the T mode. Drove me crazy. It should have been spot on for a semi automatic mode. I use T mode when I am out and about taking documentary shots like the Women's March on Saturday and I don't always have time to check the exposure. Anyway with the shutter half down you turn the dial on the back of the camera, until the exposure is correct. Easy peasy. I must have moved it once when I was taking photographs because I thought the aperture was too wide or something. Who knows what is going through your head when the pressure is on to take the right shot but the right shot is going to not be there a second later!!! So somehow I managed to change it without knowing. I have fixed it now. Thanks (hope this was helpful)
