My 5D3 arrived on Friday (guess I need to change my signature) and I shot about 400 shots with it in the studio over the weekend. I noticed that I have a higher percentage of missed focus shots than I'm used to with my 50D, particularly at wider apertures (4.0 - 5.6 or so). This is my first time using a full frame camera, is this likely a situation of the DoF being thinner on FF versus my 50D's sensor, and I just need to pay more attention to my focus point? I'm wondering if I was simply able to get away with being a little "sloppy" with focusing on the 50D and I need to untrain bad habits? I have some boudior shots where the model was laying on her back looking up at me and at F/4 her forehead is sharp and her eyes are soft. Based on my distance to the model, F/4 wasn't typically that shallow on my 50D so I suspect this is user error but I'm still curious what others think about moving from crop to FF and how that affects focusing.