The physical properties are pretty similar to Vray, therefore a real world camera. Albeit with 'cheat' controls for tuning depth of field without upsetting your exposure. To turn on DOF, all you do is select a number higher than 0 in this aperture slider. There is another section of settings for the camera settings you expect to see, F-Stop, ISO. The F-stop controls the depth of field obviously, but this can also be VERY easily tweaked using the ‘aperture’ value within the thin lens without affecting exposure. It’s very cool.
To link the camera’s focal distance to the regular C4D camera (therefore target objects etc) then the focal length here must be 0. (So far so good)
However, there’s 2 things (bugs?) that I found out after some confusion. Those values I mentioned, the 0’s: once you change them from 0, you can never go back lower than 0.01 (yes I tried typing, and also resetting to default) so once you alter those if you need to get back to NOT using DOF, or to get back to using C4D’s focal distance then you just have to make a new camera tag. I recommend leaving the focal distance at 0 and using C4D's controls, otherwise you lose viewport feedback and the target tag.