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RE: filmscanners: 35mm filmscanner choice
>> If a manufacturer was to list an lpi speck using the same method they
>> list dpi specks, they would simply be i/2 the dpi or ppi number.
>
>"half" was what I was expecting (for the ideal case, as it were), though I
>was wondering whether it is trickier than that, because resolution in
>optical terms is about distinguishing a pair (or pairs) of black lines, as
>far as I can tell. How well one has to distinguish these lines is just one
>question I could ask, but won't.
I believe there are 3 common standards for MTF:
1. the peak-to-peak (dark to light) change drops to 0.5 (the most stringent)
2. the peak-to-peak change drops to 0.1 of maximum (more liberal)
3. can you see the line? (the most liberal).
Mike Duncan
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