I need to calculate the Hyperfocal distance of a large format lens at a particular aperture. Unfortunately my knowledge of optics leaves a lot to be desired.
I will be using the following formulae: -
H= F^2/fc
Where H is the Hyperfocal Distance
F is the Lens Focal Length
f is the Lens Aperture Stop
c is the Circle of Confusion
The Circle of Confusion appears to be very subjective and is also dependant on the film format. I shall use 0.013" as my starting point for 8x10" film.
My problem is that the lens in question has a Focal Length of 120mm, but has a Flange Focal Distance of 130.7mm. What value do I use for 'F', 120mm or 130.7mm.
Can anyone advise