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 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.
George Schaub

Sigma Mount Change
Q. Can you tell me if there is a place where I can send a Sigma zoom lens to have its mount changed from Pentax to Nikon compatibility?
Alan Thitchener
via Internet

A. You did not indicate which Sigma zoom lens you have and how old it is, but I assume it's recent and in an autofocusing Pentax mount. I just contacted Sigma and they told me that due to the varying internal mechanisms found in today's autofocus zoom lenses the mount cannot be changed to adapt one mount, e.g., your Pentax lens, to fit Nikon camera bodies. I have never heard of any other firms offering this type of adapting service either. I guess you would have to purchase another zoom lens for your Nikon body.

SafeLock Tripod
Q. I am looking for a pamphlet or other information about the SafeLock FlipLock Pneumatic camera tripod, model FL. I recently acquired this tripod, which is in tip-top condition, but do not have any information about it.
H. Fernandez
Richmond Hill, Ontario Canada

A. If I remember correctly, SafeLock tripods were made in Florida, but have not been available for a decade or more. In general, most makes of tripods are relatively easy to operate and you should be able to properly use yours without any manual. There are two places I refer readers who seek instructions: John S. Craig (PO Box 1637, Torrington, CT 06790; (860) 496-9791; and Finger Lakes Photo Books (PO Box 1002, Elbridge, NY 13060; (315) 491-1188; I checked both websites and did not find the brand name SafeLock listed among the hundreds of different photographic brand name instruction books. You might want to contact them to determine if they might have the information you seek. If a reader happens to have instructions for this tripod and lets us know, we will put you in touch.

Compendium Hood
Q. I'm searching for a compendium lens hood made in the US in the late 1970s or early '80s for Nikon SLR cameras. Roughly the same size as the Novoflex PROSON compendium (25/8x31/2", front frame dimensions) and much smaller than similar products currently on the market (of which I'm aware), this compendium/matte box had no plastic parts (its bellows support frames were milled from solid aluminum and anodized black). The compendium was made in versions for both Canon and Nikon cameras, and rails were inscribed with focal lengths appropriate to each maker. Can anyone identify this item?
All of the after-market compendium lens hoods on the market now (e.g., those made by Ambico, Lindahl, Sailwind, etc.) are oversized by comparison. The item that I once owned (and foolishly sold) was sized for a 52mm accessory thread and would not fit anything larger. The Novoflex PROSON compendium is comparable, but its frames are plastic, not aluminum, and it's no longer made.
Glenn Brady
via Internet

A. Sorry I could not be of more assistance but I'm not particularly familiar with different brands of compendium hoods nor have I been able to locate data on them. The only other hood I can think of, and I'm just not familiar with many of them, is the Pro 4 from England. It holds four filters/diffusers, one on each flap, that can quickly be inserted or removed for use in portrait settings. But it's rather bulky, plastic, and might not be what you want. Possibly a reader will know of the older specialized lens hood you seek to replace and will get back to us. If they do, we will pass on the data to you.

Framing Prints
Q. I would like your opinion on framing a black and white photograph. Is it better to skip the glass or include it in the project? I've been hearing conflicting views on this and don't want to use the less desirable way. I have one photo I want to really protect as best I can while still displaying it.
Charolette Prost
Glencoe, MO

A. I checked with a friend who's in business taking and printing large format fine art black and white photography and frames all of his own work. He believes you definitely should use glass on the prints, primarily to keep dust off. You can use either glass or acrylic sheets, which are lighter and don't break easily. For the best protection use the more expensive UV glass. Other framing businesses in the area I spoke with concurred on this advice.

Images On Glass
Q. I am looking for information or a program where I can take a picture and transfer it to a glass block. Something like a rub-on or sticker. I cannot find anyone in my area who does this. I talked to Kodak and they referred me to you.
via Internet

A. There is a firm in New York that sells a variety of photographic emulsions called "Liquid Light" which can be coated onto various materials (wood, glass, ceramics, plastics, chinaware, fabrics, metal, stone, walls, or canvas) in darkroom safelight conditions. Then, using a normal photographic enlarger the image is projected onto the light-sensitive surface and developed (all while still in a darkroom) using regular photo paper developer and then fixed. It's said to have a good range of tones and the highlights permit the texture and color of the base material to show through. The firm is Rockland Colloid Corp. (PO Box 376, Piermont, NY 10968; (845) 359-5559; I believe the firm just sells the solution and does not offer any service for printing your images onto glass or other surfaces. They should be able to provide some assistance in your project. I'm not aware of any rub-off transfer method for transferring conventional photo images onto glass. However, there is an emulsion transfer process that uses Polaroid print images. You can obtain more information about this from