Posted by Marcelo (200.59.37.250) on December 30, 2003 at 05:59:53:
Hi,
I am trying to set the focus in the Aqualens for my 16mm fisheye.
The instructions say that you must find the minimum focus in the lens and align it with the zero mark. Then one must take note of the letter that coincides with the infinite mark. In the 16mm, that point is near the G. The 5 feet mark coincides with the F and so. But in the focus chart that appears at Aquatica website (www.aquatica.ca), the letters go from 0 to D. Is this chart made with apparent feet, and this explains the difference? Does it explain also that the 6 dome chart is different from the 8?
I know I shouldn't care about exact focus points, because of the extreme depth of field of the lens, but just want to know where to put the focus, so my foreground subject and the subjects beyond and at infinite, are both in focus.
By the way, how close are subjects underwater? One third or one quarter closer? All books that talk about apparent distance says that, but none tells it exactly.
I mean, 3 apparent feet are really 4 measured feet? (just to make a chart).
Thanks for your help and happy holidays,
Marcelo