autofocus

I know there are many differences between the 5D Mark IV and the A7R IV. I think most would say the A7R IV is in another class in terms of performance. However, according to the website imaging-resource the 5Dmark IV is considerbly faster at autofocus than the A7RIV. I was very suprised and a...

I'm predominately shooting wide angle pelagic life around 60-110 ft: Is there a significant difference in the AF when I'm that deep with limited ambient light? Sometimes I want to zoom in on something a bit further away, maybe 50-100 ft away, is that just too far to shoot underwater at that...