A large format photographer's vade mecum

Free software for View Camera calculations

by Bob Wheeler for The Large Format Page

All the files are also available directly from Bob Wheeler's ftp site which should be referred to for the latest update. Everything on this page is copyright Bob Wheeler (C) 1999 and is archived here courtesy of him for the convenience of this site's readers.

What is this vade mecum

When I started in large format photography, I was unable to find adequate instructions for many fiddling problems in the books I consulted. I found exhaustive discussion of light and photographic materials, but little help on the practical problems. Lens tilt, for example, seemed as much a mystery to many authors of photography books as it did to me --- at least if they knew its incantation, they chose not to reveal it.

As near as I could make out, tilting the lens was something to be done by cut-and-try --- focus on something, tilt the lens a bit, focus on something, adjust the tilt, etc. until all parts of the subject are in focus. (A discussion of this procedure in exquisite detail may be found in H. Bond (1998) Photo Techniques, May/June.}. I tried this a few times with middling success, but found it hardly a satisfactory procedure: if for no other reason, than that it takes a long time. I am sure the information exists in the technical literature somewhere, but in exasperation I sat down and derived the equations from first principles. By that I mean I went back to a theorem of projective geometry due to Desargues which underlies the rules artists use to produce perspective drawings, and derived the lens equation relating the focus distance, the lens-film distance, and the lens focal length. >From this everything else follows.

These programs are written for use by practicing photographers. The aim is simply to make a photographer's life a bit easier by encapsulating arcane technical details in computer programs. These details are available for those with a mathematical bent in the technical notes.

Programs and docs

The suite is for use on hand held devices. In this upload, support is provided for the TI89 and HP48Gx calculators, the 3Com Palm device, and CE devices.

Download instructions and documentation are provided below. Curious individuals might like to download some of the documentation to get a feel for what is available.

The program suite comprises 44 programs:

The documentation files are .pdf files which are readable with the free Adobe Acrobat reader.

The program files will unzip to program files suitable for downloading and installing on the appropriate devices. After unzipping, see the XXXXinst.pdf files for download instructions. No download instructions are provided for the Palm device, since downloading is an integral part of the system and is described in the Palm manuals. Here are the programs and docs for version 1.1. For updates, please refer to Bob Wheeler's ftp site. Version 1.3 has an additional resolution calculation, and now output the distance the top of the front standard moves when tilted -- this enables those without an angle scale to use the tilt calculation.

Documentation for the HP48Gx calculator, HP48Gx programs

Documentation for the TI89 calculator, TI89 programs

Documentation for the 3Com Palm device (OS 3.1), palm program

Documentation for palm-size PC's (OS 2.11), CE program

Technical notes

For the mathematically inclined, there are technical notes about View Camera mathematics. These notes do not comprise an exposition or tutorial but are simply a set of notes that were made while thinking through the problems. They are somewhat dense, and not recommended reading unless one really has to know the details. They give the equations used in preparing the programs. The notes are made available because some of the programs make useful calculations that are not well known, and for which references are not readily available. The notes change from time to time with additions and emendations -- I am still a student of photography, so do not judge the notes too harshly.

Technical notes about View Camera mathematics (link to Zipped pdf from Bob Wheeler's site)

Choosing a device

The calculators are the least expensive devices. Of these the TI89 is probably the better choice. It is a newer calculator with significant Built-in capability, which can be achieved by the HP48GX only with add-on software. It should be noted that the HP48 comes in several Models, and only the most expensive one, the HP48GX, will run Vade Mecum. The TI89 is much cheaper.

The personal digital assistants (PDA's) may be more suited to the needs of a photographer, since one may use them as field notebooks to record photographic parameters and descriptions. The entries in the notepad can be picked up by a connected PC and printed out.

Of the several PDA's now available, I recommend the 3Com Palm devices, Especially the Palm IIIx. Its screen is visible in bright sunlight, and it runs on inexpensive replaceable batteries which last a long time.

The others all run Windows CE, which is a more capable operating System, but the hardware is not as yet up to the quality of the Operating system. Their screens are all difficult to read in one way or another. The HP Jornada 420's screen is not visible in bright sunlight, and although the Compaq Aero 2120's screen can be read in bright sunlight, it has a glare which makes it difficult to view indoors. They all have built in batteries, which must be recharged. The Jornada 420's batteries last little more than an hour, which means that one must carry spares. The Aero is better in this regard, but less satisfactory than the 3Com devices. Unfortunately for me, the Vade Mecum program for the CE devices looks better than does the one for the 3Com device, because of the greater flexibility in the CE operating system.

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bwheeler@echip.com