[MF3D.FORUM:377] Re: 1/fl

["Oleg Vorobyoff" <olegv@xxxxxxxxxxxxx>]

Paul Talbot wrote:
>If I'm following correctly, 1/fl is a quickie way to keep from
>exceeding 1.2mm OFD in 35mm, given normal scenes that include
>infinity.  In MF, 1/fl in a normal scene that includes infinity
>would also tend to keep OFD under 1.2mm, right?  And that's well
>below the target maximum of 2.7, so 1/fl doesn't directly help
>as a shortcut for MF.  It would need to be scaled up to 8/3 * 1/fl.
>With an 80mm lens, that puts us back at 1/30.  Then to maintain
>a constant OFD shooting the same scene with a 240mm lens, the
>new base would be (8/3 * 1/240) or 1/90.  Am I warm?


Clear as a bell to me.  I wish I could have written that.  I have been using 2/1
scaling between the 35mm and medium formats, resulting in a 2.4mm maximum OFD.
Sounds like that was way too conservative.

Oleg Vorobyoff