Just to add on the focusing side of things, what I had done as I didn't have a bhatinov mask. Is focus the lens in daylight (eg building/tree etc) to infinity then lock it in place with a couple of pieces of masking tape. That way I just needed to setup and shoot. Depending on the weather and atmos conditions, sometimes I would get a minimal amount of subs out of focus.
Moving forward for lens, I too am deciding on getting the tokina as I have heard veryngood things about them, so I'm sure you cannot go wrong.
Rob
|