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1. Originally Posted by maarten m
one more question: you say the ND-scale is exponential.
does this mean that a 10pt shift does not exactly accord to 1/3 stop
but is different whether it's from 5 to 15 or from 45 to 55?
i'm getting a bit confused here ...
Right, I can see that. My confusion was over how to compute the conversion between exposure time and the numbers on the ND filter scale. That scale is really graduated in 1/30th stops, of course, so that d(30):d(29)::d(1):d(0), where d(n) is the density of the given setting. In other words, 10 points equals 1/3 stop, anywhere on the scale. My final table assumes this, whereas the former one assumes that d(30)-d(29)=d(1)-d(0). It's really only interesting at the level of 1/6 stop differences.

I'd love to know how my calculations work out in practice! If you do test this, please report back!

-tih

2. Oh, and Maarten: I don't know if you have the current URL to Meopta's collection of documentation? You can find it at http://www.meopta.com/CCE/DownloadFileList/ - click on "Discontinued Product Manual" for the old stuff!

-tih

3. hey tih, i already found that manual, but thanks anyway.
when i get some time to work on your diagrams, i'll make some tests and see how they work out.
keep pushing me though, or i might forget

regards,
mm

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