Originally Posted by f1ea
Great article, thanks for sharing!
With 1:1,618 as a ratio for a single focal point... what would be the ratios for 2 focal points??
Figure the distance from one side of the tank to center your main focal point. That becomes your new 'side' to calculate a second focal point.
Optimally you would have them toward opposite sides, rather than having them both shifted to the same direction.
For example, in a 5' long tank one focal point would be centered 27.5" from one end of the tank. The other would be centered 17" from the opposite end of the tank, and would be a secondary, rather than a primary, focus.
If you have a large enough tank and are able to work in varying levels such as hills, then it may be feasible to center the secondary focal point 17" from the first one.