steve_down

The hyperfocal distances are not the same, if you use the same means of calculating the minimum acceptable circle of confusion.

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Most calculations or tables I've seen use a tolerance of 1500 or 1750 circles per diagonal, so your minimum C of C would be sqrt(height^2 +width^2)/1750.

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Medium format, by virtue of its larger negative/slide size, provides a higher tolerance for this diameter. If you look at the preceding equation, it also becomes apparent that your hyperfocal distance {(focal length^2)/(f-number)*(min C of C)} will change slightly between different medium formats.

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Hope this helps.

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By the way, I have a few interesing PDF articles from Shutterbug, which describe how depth-of-field can be more easily maximized through infinity focus and selective aperture. It also has an interesting discussion of the applicability of the current DOF equations. You can probably get them of Shutterbug's Web site (I've forgotten where they live). If you can't find them, contact me, and I'll ZIP them out to you.

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Steve

From the 1996 FujiFilm Data Guide:

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1/4000 to 16 sec: no compensation

32 sec: +1/2 stop compensation

2 min: 2.5R filter +1 stop

8 min: not recommended

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Hope this helps.

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Steve