### Scheimpflug Calculations

greenspun.com : LUSENET : Large format photography : One Thread

Has anyone written a simple calculation program that could operate on a palm pilot or similar machine that does all the calculations? Can you point me to an online resource that has all the necessary formulae? It seems like it would be useful to be able to enter lens focal length, distance to subject and relative anglle of desired focus plane and have a program caluclate the angles to preset into the camera. I'm sure there would have to be adjustments made but this would be a useful tool to get "in the ballpark" before putting your eye to the glass.

-- Dave Schneider (dschneider@arjaynet.com), November 25, 1998

www.zonevi.com

look for exposure calculator

-- al (nissar@idt.net), November 25, 1998.

Well...since all 3 planes need to converge at the same point (such as ground, film plane, and lensboard), just eyeballing it seems to get you into the ballpark.

-- Ron Shaw (shaw9@llnl.gov), November 25, 1998.

You might want to check out:

http://www.darkroom-innovations.com/Software/ExpoDev/expodev.html

http://www.darkroom-innovations.com/Software/FX-795P/fx-795p.html

I have no experience of them though.

Tim A

-- Tim Atherton (timphoto@nt.sympatico.ca), November 25, 1998.

I checked out the Darkroom Innovations software in detail. Its purpose is to control emulsion density on B&W film. Pretty sophisticated stuff and very impressive if thats what you want. It does not, however work as a general purpose exposure calculator.

I have considered writing such a program for PalmOS. Input would be:

1. Film (including reciprocity data) 2. Lens (available/preferred apertures) 3. Filters (filter factor) 4. Distance of nearest object to be in focus (actual or extension) 5. Distance of farthest object to be in focus (actual or extension) 6. Several meter readings with desired zones

It supplies:

1. Aperture (for depth of field) 2. Distance to focus (hyperfocal for aperture) 3. Shutter speed, accounting for: a. aperture b. bellows extension c. filter factor d. film expansion/contraction to achieve desired zone placement e. reciprocity correction

I suppose there ought to be a way to calculate Scheimpflug movements, I just haven't figured out how yet.

Anybody interested in a program like this?

-Ben

P.S. Thank you Quang-Tuan Luong for teaching me how to spell "aperture".

-- Ben Diss (bjdiss@interport.net), November 25, 1998.

"Scheimpflug Calculations" Has anyone written a simple calculation program that could operate on a palm pilot or similar machine that does all the calculations?

Doesn't Rodenstock sell a "calculator" that does what you're asking? Midwest Photo sells it for about \$30. I've seen it. It's a paper "calculator," for which you select the lens, angle of focal plane, etc., by moving the circle paper cutouts and then line up the points and it will theoretically give you the best angle to preset the camera and necessary f stop.

-- Howard Slavitt (nverdesoto@earthlink.net), November 26, 1998.

http://fox.nstn.ca/~hmmerk/ (by Harold M. Merklinger) has all the formulae.

With your surname, Dave, don't you have it all already in the family?!

-- Alan Gibson (Alan.Gibson@technologist.com), November 26, 1998.

Way before you figure out all the math, do the proofs & double check I will have set up the camera, composed, focused, shot & backed up with an in camera dupe and am away for the next image. Why make it harder than it needs to be. Focus on the ground glass & watch your focus as you swing & tilt & rise & fall to your hearts content. When the batteries die in the field you will have to do so anyway.

-- Dan Smith (shooter@brigham.net), November 26, 1998.

Try Harold Merklinger's book "focusing the view camera" or his website (forgot the address, but you should find it through the search engines Lukas Werth

-- Lukas Werth (lukas@werth.sdnpk.undp.org), November 30, 1998.

I use the Dan "The Shooter" method of swing/tilt cypherin'. The ground glass doesn't lie. 99% of swings/tilts are very small so if you need to "calculate" these angles take up painting. Just kiddin'. Most of your swings and tilts are quite small unless your're shooting still lifes and even then you can guesstimate pretty closely just by "lookin' at the glass". Calculating this stuff in the field takes all the fun out of it. Just point and shoot.

-- james (james_mickelson@hotmail.com), December 04, 1998.

Check out Bob Wheeler's free software, just installed on the LF page.

-- Quang-Tuan Luong (luong@ai.sri.com), May 07, 1999.

Just to be precise about things, I must correct Ron. You want the three planes he mentioned to intersect in a line, not a point.

-- Ellis Vener (evphoto@insync.net), May 07, 1999.

To great many LF photography, Scheimplug rule is the only rule they know of. But in fact, the popular Scheimflug rule a lone is not good enough the find the right focus.

Scheimflug had a much neglected Scheimflug Second rule; and thanks to the effort of Harold Merklinger, this rule has being rediscovered and described in detail in his book "Focusing the View Camera" as The Hinge Rule. It stated that the front focal plane, the plane of sharp focus and the parellel to to film lens plane must intersect at a Hinge line. With this Hinge rule, or Scheimflug Second Rule, focusing view camera becomes quick and simple, no more eyeballing, try and error. He wrote" in one outing,,, I had taken four photographs allwith different focus settings and in two locations in the space of eight minutes. That is 2 minutes per picture, vs 20-30 minutes per picture set up time by conventional method

You will do your self a great favour by BUYING THE BOOK. Forget about get the info from Harold's web page. Do you think he gave away all the info to sell the books ?

-- martin tai (martin.tai@capcanada.com), August 31, 1999.