setting my standards with hyperfocus

[sf]

I have this camera. It is a Cambo with a 75mm Fujinon SWD on it. I have modified it with a viewfinder, and am planning on using it as a landscape only camera.

I have been searching for information on how to determine the lens to focal plane distance based on hyperfocal distance. I have found only calculators for finding hyoerfocal distances at given apertures and focal lengths.

They claim a 1.83 meter hyperfocal distance for my lens at f32. How far should my lens be from the film when focused for this hyperfocal distance? More accurately, do I measure from the shutter or from the very 'back' of the lens (closest to the film)? What I want, is to anchor my standards at this distance permanently so that i can whip this thing out of its case and fire off a shot without dealing with the painfully obsessive task of focusing on that little ground glass when time is of the essence. Or when time is not.


thanks for any help

 

[pvdhaar]

You can use the following formula:

1/(f+d) + 1/s = 1/f

Where d is the lens extension, (d=0 when focussed at infinity), f is the focal length, and s is the distance from the film plane to the subject the lens is focussed at.

 

[pvdhaar]

On reading your intended use for a second time, I definately think you should focus at infinity. Check out http://www.trenholm.org/hmmerk/DOFR.html for a good explanation..

 

[sf]

thanks for your help

thanks for your help

I just read through the website. Thanks for the help, this is important information.

 

[Doug]

I think it would be useful to create a focus distance scale as a handy reference in the field. Folding flat bed cameras often have such a scale attached to the bed, but assuming your Cambo is a rail camera, then I'd make up something that can be used like a tape measure from standard to standard. Instead of inch/mm marks (or perhaps in addition to those) it will have distance markings.

I'd make it by focusing with the ground glass and magnifier on objects at know distances, and make measurements of the corresponding distances between the standards.