I have the still version (with the Invercone attachment). It's makes a good back up meter IF you remember these three things:
Good - No batteries
Bad - Calibrated in Weston speeds, not ISO
Ugly - Pretty much useless in low light
I also have the still version, Bob. But I have never seen an Invercone except on the web.
Good - No batteries - I agree. Battery independence is wonderful. And they have no memory like CdS meters have.
Bad - Weston speeds - Maybe not a big problem. Multiply ISO by 0.8. Shooting 400? Set the meter to 400 x .8 = 320. Here is where I got that information:
http://daniel.mitchell.name/cameras/westonmtr/westonmtr.html
One may discover by comparing readings with a gray card and a known good meter that the difference is a little more. Whatever it is, just remember the multiplier needed to get from ISO down to Weston. It was 0.8 for my meter, but may be 0.6 for someone else's meter. Once that
multiplier is known, it seems reasonable that it should work for converting any ISO to its equivalent Weston speed for the meter in question.
I read that Edward Weston came up with his own ratings because he felt the film manufacturers were cheating, by over-rating their films' sensitivity. The article said that the Weston numbers were 1/3 stop slower than the inflated ASA numbers manufacturers claimed.
http://pub20.bravenet.com/faq/show.php?usernum=1678719246&catid=3361
FWIW, newer Weston meters are now calibrated the same as ASA/ISO. Brand spanking new ones can still be bought in England. But they are very expensive, over 200 Euros.
Ugly - Pretty much useless in low light. - I agree, but there
is a
free 5X light amplifier, so to speak. A 90% reflectance sheet of paper, or the white side of a gray card. That gives about 2-1/4 stops of additional sensitivity in low light (5X).
For example, if the meter's report from the white card says shoot f/2 at
1/20th, then change that to
5/20th, which is 1/4th second.
Henry