I just purchased a used 5D Mark III and I feel like something in the way it focuses is not right. I hope some of the Mark III owners out there can help me.
Here is the deal - while in the fully automatic mode "A" everything works fine. The camera picks up its subjects and focuses quickly using the shutter button pressed halfway. But when I switch to P, Tv, Av the focus will not work with the shutter button half press, I have to use the AF-ON button for it to activate and get focus. I shot a 30D for many years and never ran across this.
My question - Is this normal? Is it designed this way? Or do I have a software issue in the camera? It has the 1.2.1 Firmware installed.
Thanks for all your help.