Here Is A Quick Tip List On Letters
For The HELP! Desk:
Please confine yourself to only one question per letter. Both postal letters and e-mails are fine, although we prefer e-mail as the most efficient form of communication. Send your e-mail queries to email@example.com with Help in the subject header and your return e-mail address at the end of your message. Although we make every effort, we cannot promise to answer every HELP! letter.
When sending a response or suggestion that refers to a published letter please include the month and page of the original question.
All postal letters to HELP! must be accompanied by a stamped, self-addressed envelope to be considered for reply. We will respond to e-mail queries with an e-mail.
120 IR Film
In the November 2006 issue a reader questioned you about 120mm infrared film. At one point in time you could buy re-spooled Kodak 70mm Aerographic film from the following website: www.davidromano.com.
J. W. Hicks
Saint Louis, MO
Thanks for the information, but the reader asked about color infrared, which has become practically impossible to obtain. I checked the website you mentioned and found that this infrared film is black and white, which has been cut down from 70mm perforated Kodak aerial film to fit onto a 120 spool. It costs $20 per roll with a minimum order of three rolls plus shipping and handling. Even this film is in short supply--but it is a source.
Beseler 18" Lens Query
We received a number of responses about the 18" E.F. lens query in our January 2007 issue. We thank readers for their prompt and courteous replies. The current address of the company is Charles Beseler Company, Executive Office, 1560 N.W. Blvd., Vineland, NJ 08360; (800) 237-3537.
Re: the inquiry from Daniele about the Beseler 18" E.F. lens. Beseler is still in business so they may be able to shed some light on this. I believe that the lens is from an opaque projector or a Slide King projector which was generally used for lantern slides, which were 3 1/4x4" in size. Beseler made both types years ago and they also made an overhead projector. Daniele's lens could have come from any of these.
When I was teaching about 40 years ago we used Beseler opaque projectors and Beseler overhead projectors. From the description of this lens, I have a hunch that it was one of the opaque projector lenses. Hope this helps solve the mystery.
Charles Beseler Company, in addition to enlargers, made a line of opaque projectors that used a lens like the one described. They were about 5" in diameter, in a plain tubular mount, and had no diaphragm.
Chris Lydle, CPC
Color Temp Meter Reference
Re: Thomas E. Chipp's question about the Eastman Color Temperature Meter in the January 2007 issue. Photography: Its Principles and Practice, by C.B. Neblette, D. Van Nostrand Company, Inc., Fourth Edition (1942), mentions the Eastman Color Temperature Meter (pg. 169) and gives the following brief description of its operation: "...two images of the subject are seen, one through a monochromatic filter, the other through a dichroic (two colored) filter. These two fields are made to match by a wedge which controls the transmissions of the two filters. The wedge is calibrated in color temperatures so that, when the transmissions of the two filters have been equalized, the effective color temperature of the source is indicated on the dial of the instrument." The source cited for this information is Lowry and Weaver, Journal of the Society of Motion Picture Engineers, Vol. 32, pg. 298 (1939), which would seem to support your speculation that this device might have been used for motion pictures rather than still photography.
One reader contacted me who has the meter, and instruction book, and I put him in touch with Mr. Chipp so he could obtain a copy of the book. As you indicated, it would seem that this device was intended for the motion picture industry. I do appreciate your looking this up and forwarding the reference to me.
AF And Diopter?
I read the letter to the Help column in the January 2007 issue about autofocus issues after a Maxxum camera was cleaned. My guess is that the reader accidentally moved the diopter adjustment on the camera's viewfinder. Of course, if the camera doesn't have a way to adjust diopter, my theory is bogus. Then, I'd suspect the eye-tracking section. Just my two cents.
Early Maxxum SLR cameras included a 5000 (1986), a 5000i ('89), a 5xi ('92), then in '94, a 500si. Many Maxxum models have a diopter adjustment. The 5xi has both a grip and eyepiece sensor that starts the automation as the camera is gripped and held up to the eye. This should not, however, affect the focus. I trust that the reader was able to get the problem resolved, possibly by having the dealer who originally worked on it check into the focusing problem. We do appreciate your suggestion, which would make sense if the camera had a diopter adjustment.