Unusual AI modifications

This page focuses on the more unusual AI modifications I�ve done. Most commonly these are on aftermarket lenses such as Vivitar. Typically these lenses cannot be modified in the same manner as Nikkor lenses. Often the solution to making these lens AI compatible is to fabricate some kind of a special fixture that adds the AI meter coupling ridge to the lens. It is usually not possible or practical to add the EE coupling pin to these lenses. The lenses shown illustrate some of the variations involved in these unusual AI modifications on Nikkor lenses. I�ll update this page with additional images as I do these special projects. To get a bigger and better view of each of the lenses, just click on a picture to enlarge it.

Typically non-AI Nikkor lenses have metal on the aperture ring that extends past the lens mount. To do an AI modification, you machine some of that additional material. On this Vivitar 28mm 2.5 lens, the aperture ring ends flush with the lens mount, so there is no additional material to form an AI indexing ridge. The solution is to fabricate an add-on tab to serve as the AI ridge. In this case, there was also another challenge: There was no room to put the AI meter prong and ADR strip. The solution was to incorporate the meter prong into the fabricated add-on fixture. Fabricated from steel and painted black to match the lens, the add-on coupling device and meter prong were screwed and epoxied in place. A standard ADR strip was cemented over the addition to complete this AI modification.

The owner of this Vivitar 400 5.6 lens had no intention of using it on a camera that wasn�t AI compatible, so there was no need to add a meter prong. Like the similar Vivitar 28 2.5 modification, this modification required adding a tab rather than machining away existing material. Again, there was no need for an EE tab, so that also was eliminated. The tab, painted to match the lens, was screwed and epoxied into place.

The first non-Nikkor AI modification I did was a Telesar 35mm 2.8 lens. The lens itself was not worth much, so it emboldened me to try modifications on non-Nikkor lenses. It was the first time I used an external fixture screwed to the lens, and it worked just fine.

The most unusual modification I've done to date involved a rare Zoom Nikkor 200-600 lens. This lens was never designed to meter couple with even the non-AI Nikon cameras, as it's maximum aperture of 9.5 is beyond the range of the early meters. My fixture-type modification allowed it to meter with AI cameras.

Although my focus is on AI modifications, from time to time I am asked to provide other related services and even basic camera and lens repairs. Most of these are handled on a case-by-case basis, but some common services are listed here. Contact me with specific needs.

Aperture Direct Readout (ADR) strips: Many people have lenses that were "AI'd" by a repairman who did something less than the more complete AI modifications I do. Most commonly it is missing the ADR numbers. I sell ADR strips in a plastic-laminated, self-adhesive form. Strips cost $2 each plus $1 shipping and handling in the United States. Please specify the aperture range required when ordering. I strongly recommend ordering two strips for each lens, as it's a little tricky to install them, and that gives you a spare in case the strip wears or pulls off in the future. The strips come with instructions for installation.

Meter coupling prongs: Since I generally machine the existing prong when I do an AI modification, I don't normally permanently remove the prong or substitute a replacement prong. Still, I do seem to always have a few spare prongs on hand. I am willing to sell these as the need arises and my supply permits. Current price is $15 for an old style prong plus $1 shipping and handling. I do not have AI prongs in stock. They can still be ordered as replacement parts from Nikon.

Camera and lens repairs: I am not a full-time repairman, so this work is limited by my time and experience. Contact me with the specifics of your need, and I'll see if I can help. I specialize in manual focus, mechanical Nikon cameras with a special emphasis on Nikkormat models, but I do tackle other brands and models from time to time.

The best way to ask a question or get more information is by e-mail at wdshpbiz@aol.com.

Lenses for modification should be carefully packed. I recommend USPS Priority Mail with confirmation. Insurance is at the shipper's option. I offer customers the choice of flat-rate shipping charge of $8.50 per lens for confirmed Priority Mail, or they may choose to send an amount equal to the cost of shipping by some other method. I offer a combined shipping discount for multiple lenses sent at the same time in the same package. Any insurance requested must be paid for in advance. All work requires payment with order. I accept checks, money orders and PayPal payments to my email address of wdshpbiz@aol.com. On receipt of the lens, I'll e-mail you confirmation of its safe arrival and an estimated time of return. Standard AI modifications usually take a week to 10 days depending on current workloads. Ship all lenses to: