Quote Originally Posted by Bill Burk View Post
Right.

I think they only said 2 stops as a suggestion, since you can't practically set 1 2/3 stop.

But you can carefully note meter reading to nearest 1/3 stop, add 1 2/3 stop filter factor. Then sometimes the correct exposure (including filter factor) will fall exactly. Or you can include filter factor in the EI that you set on a handheld meter.

When I go out, I often pick the filter in advance and use it the whole day. I set the EI on my handheld meter to include the filter factor. When I go inside, then I take the filter off and set EI on the meter to rated speed.

If you're using a modern era bells-and-whistles (35mm or even medium format) camera, setting 1.6 stop filter compensation is easy if there is provision for choosing stepping among 1 stop, 0.5 stop or 0.3 stop. I regularly do 1.3 and 1.6 stop compensations for filter-unrelated scenes on an ancient EOS 1N.