A. In general, the rule of thumb for lens sharpness is any lens, no matter which film format it covers, will be at its critical sharpest aperture when used at two stops down from the widest open aperture available on that lens. Thus your 135mm f/4.7 lens in theory should be sharpest stopped down to about f/11. But, as you are aware, you will obtain more depth of field when the lens is stopped down farther to f/22 or f/32, or smaller. I believe you are worrying needlessly about how much critical sharpness is obtainable from these two good, but very old, lens formulas. I realize you want to do large format landscape imaging, but you can cut your film costs considerably if you could locate a rollfilm back for your old 4x5 camera. I have a Graflex rollfilm back for my 4x5 Super Graphic, which replaces the cut film back. Other types of rollfilm backs simply slide into the spring-loaded opening where the 4x5 cut film holder normally fits. Admittedly, the resultant 6x9cm image is about 1/3 smaller than the 4x5" cut film image, but the cost of 120 color transparency roll film with eight exposures and processing is far less than 4x5 sheet film and processing. Besides, you would not need a darkroom to load the holders.

Disc Processing
Q. I have a couple of disc negatives from a Kodak disc camera that are about 17 years old. I am having trouble finding anyone who can develop these negatives. Please advise any services you may be aware of that can help.
Bill McClay
Collingdale, PA

A. My files show several firms that still process and print the old disc format negatives. Be sure to contact them first to determine if they still do this work and get some prices before sending any negatives to them. Processing older disc films and discontinued processes such as C-41 CN and E2 and E4 chrome: Film Rescue International, Box 44, Fortuna, ND 58844; (800) 329-8988; www.filmrescue.com. Another lab known for handling older films is: Rocky Mountain Film Lab, 560 Geneva St., Aurora, CO 80010; (303) 364-6444; www.rockymountainfilm.com.

Subminiature Processing
Q. I recently came across an old Minolta 16 camera I bought over 25 years ago. It still had some (16mm) film in it. Do you know if there is anywhere I can get this film developed? I have called Minolta and they were of no help, but suggested I
contact you.
Fred Finkelberg
Pomona, NY

A. Locating places to process and print 16mm film today is difficult. My first suggestion is to check out the website devoted to subminiature enthusiasts where you can locate all types of information. Log onto www.subclub.org, which lists places offering 16mm processing, film slitters, and camera sales. Another web source I learned about recently is www.pixelpete.com; Pete has slitters for cutting 16mm down from 35mm film and does subminiature processing, but he has no film or cassettes. Hopefully, you can find somebody who can process your old 16mm film. Be aware that latent images on exposed but unprocessed decades old film may have deteriorated and not produce printable negatives when processed today.

Premo Cameras
Q. I'm looking for some information on an Eastman Kodak No. 3A folding cartridge Premo camera. This camera takes 122 roll film. I got your contact information from the Kodak website. The camera is in very good to mint condition. All of its parts still work. I'm looking to get an estimated value for it and possibly sell it if the opportunity presents itself.
Laura Papadopolous
Trinidad, CO

A. Your vintage Kodak folding camera was made from 1917-23. The generally recognized bible for pricing older cameras, the 11th Edition of McKeown's Price Guide to Antique & Classic Cameras, 2001-2002 gives a current price range of $12-$20 for your camera.

Newton Ring Problems
Q. I recently purchased a Leitz Focomat 1C enlarger and am getting Newton rings on the prints. This is the older black version 1C and did not come with an anti-Newton ring glass. Would you possibly have any good leads as to where I might find this attachment? I think it's become somewhat rare.
Medford Taylor
via Internet

A. I called the technical people at Leica U.S.A. and they told me they have not been able to get this type of anti-Newton ring glass for their enlargers from Germany for about five years. What they recommend trying is to make a mask out of black paper and placing this on top of and around the negative to keep the condenser from making close pressure contact with the negative, which is what usually generates the undesirable rings. They said to try various thicknesses of black paper, but not overly thick or thin.

Rewind Problems
Q. I own a Minolta Maxxum 7000. I have trouble taking out the film--it doesn't rewind. I changed the batteries, but am still unable to get out the film. Can you help me?
Ahmad Tabalvandani
via Internet

A. I assume you mean the automatic rewind does not start when you get to the end of a roll of film. If so, I have two suggestions. Have you checked the battery contacts at each end to be sure it is powering up the camera? If the LCD lights, the battery contacts should be OK. What about using the mid-roll rewind function? There should be a recessed rewind button on the body somewhere. It will allow you to start the power film rewind anytime before the film reaches the end of the roll. Just press in on this tiny button with your thumbnail and the rewind should start. On my slightly newer Maxxum 8000i it is one of the several buttons located under the hinged door on the right end of the body. Hope one of these ideas works for you.

Values Requested
Q. I have a 420 Polaroid Automatic Land camera and a 40 Revere Model 4-D magazine cine camera. I wish to know if either or both are worth anything.
Betty Moudry
Rock Island, IL

A. My prime pricing reference book shows the folding bellows Polaroid Automatic 420 camera of 1971 has a current value of $1-$10. I could not find the Revere model 4-D listed in any of six different reference books. There was a 16mm magazine Revere, but not with the model number you provided. Truthfully, very few movie cameras are listed in these reference books because, in general, old 8mm, Super 8, and even 16mm cine cameras have very little value today. Sorry that there is not better news about your old photo equipment.

Super Pilot Repair
Q. My old Gossen Super Pilot SBC needs repair. Who can you recommend for this type of service? And by the way, this particular service of yours is quite valuable--thanks!
Rick Matson
via Internet

A. I just spoke with my contact at Bogen, the firm that currently imports Gossen meters. They tell me that some parts are still available to repair your old Super Pilot SBC meter. You can reach them at: Bogen Imaging Inc., 565 East Crescent Ave., Ramsey, NJ 07446; (201) 818-0060 (the direct number for their repair department); or look under service and repair on their website at: www.bogenimaging.us. It is suggested that you call first before shipping the meter to them to determine if parts are still offered for your particular service needs. Thanks for your kind comments about our HELP! service.