I bought two 3.6mm turrets. I love the image, but I need performance in the ~6 feet distance range, and these see really tuned to be 15 feet + which doesn't work for my use case.
Yes, the closer the cam/focus, the less depth of field. Even at the longer end, the range for good focus is limited. e.g., If I focus on the far end, near focus is lost from about mid-pond. Once you get to greater distances that starts to improve.