### Rodenstock calculator

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

The HP Marketing website says that the Rodenstock calculator computes Schleimpflug angles and depth-of-field. How does it work? Is it a useful accessory? Thanks.

-- Josh Divack (jdivack@worldnet.att.net), May 07, 2002

works great and is very useful. I mainly use it for calculating the hyperfocal point however.

-- Ellis Vener Photography (ellis@ellisvener.com), May 07, 2002.

Bob Wheeler has a very useful series of reviews of LF tools. The Rodenstock calculator is one of them. I use his (Freeware!) Palm program VadeMecum, and find it very useful.

http://www.bobwheeler.com/photo/index.html

-- jason (sanford@temple.edu), May 07, 2002.

Practically, is this accessory more for the studio, the field, or both? I'm using a Wisner for landscape, etc. and have no easy way to calculate angles, etc. with any degree of precision. Do I have a need for this accessory? Thanks.

-- Josh Divack (jdivack@worldnet.att.net), May 07, 2002.

Josh, the Rodenstock calculator is worth having - its not expensive. I sometimes use it to double check when in the field but its probably more at home in the studio.

-- paul owen (paulowen_2000@yahoo.com), May 07, 2002.

Why not just ask us to mail you the literature on it. We can mail you some.

-- Bob Salomon (bob@hpmarketingcorp.com), May 07, 2002.

I use it for field work.

-- Ellis Vener Photography (ellis@ellisvener.com), May 07, 2002.

How does it work? Part I, The Depth of Field calculator:

To start with, point the camera at your subject and if you have tilted the base of the camera, re-erect your front and rear standards to vertical. 1.) roughly determine the angle between the bed or monorail and the lens axis (with front & rear standards upright).

2.) Set the film format you'll be working in. The calculator has scale settings for 35mm through all of the most popular medium formats, to 4x5, 5x7 & 8x10, in both English and Metric measurements.

3.) determine the scale of reproduction. I assume this means the scale at which the object being photographed will be reproduced on film.

4.) determine the extension difference between the near point you are focusing on and the far point you are focusing on. The calculator has an 8cm ruled scale that you use for this,Now refocus the camera to the ideal hyperfocal setting for that f-stop by moving the standard half way between the two points. In other words if the difference was 5cm between your near and far points, then move the standard 2.5 cm towards your starting point.

5.) Opposite this number will be the f-stop needed to achieve this depth of field. Set this f-stop on the lens. .

Now lookat the number 6 calculaton. the Belichtungszugabe. this will tell you if there is any added expsre necessary for for bellows extension.

All of this takes about a minute or less to do.

I haven't used the Scheimpflug calculator so I cannot comment on how easy it is to use but it looks equally straightforward.

-- Ellis Vener Photography (ellis@ellisvener.com), May 07, 2002.

Ellis, thanks very much.

-- Josh Divack (jdivack@worldnet.att.net), May 07, 2002.

The rodenstock calculater is a usefull tool, the scheimpflug rule is not so easy to understand. The dof-calculator is great. not heavy - not expensive. Marcus Schwier

-- marcus schwier (marcusschwier@hotmail.com), May 07, 2002.

Once you determine the bellows extension difference between focusing on the nearest point and the farthest point in the scene you can use published tables to determine the necessary aperture without buying a depth of field calculator. Linhof publishes such tables and others were published in Photo Techniques magazine a while back (I believe these tables are cited in Tuan's focusing article in this home page). I'm sure they've been published elsewhere. The Linhof tables are based on an 8x10 print and if you decide to stop down one stop more than the tables call for with 4x5 (e.g. if you want to be on the safe side or if you think you'll be printing larger than 8x10) they are particularly easy to use because the necessary aperture corresponds exactly to the bellows extension difference. E.g. if the extension is 1.6 mm or close to it, the tables say to use F16; if the extension is 2.2 mm or close to it, the tables say to use F 22, if the extension is 3.2 or close to it the table say to use F 32, and so forth up the aperture scale. So you don't need to carry anything around with you. Of course all of these tables (and, I assume, the Rodenstock depth of field calculator) have to make assumptions about the size of the circle of confusion that is acceptable to you.

-- Brian Ellis (bellis60@earthlink.net), May 09, 2002.

AFAIK the Rodenstock calculator is -- at least officially -- not available any more ('cause of the logo).

Alex

-- Alexander Selzer (selzer@gmx.net), May 09, 2002.

"AFAIK the Rodenstock calculator is -- at least officially -- not available any more ('cause of the logo). "

We have lots in stock if anyone has a dealer in the U.S. who wants some. They will be available for quite some time here.

-- Bob Salomon (bob@hpmarketingcorp.com), May 09, 2002.