Using old Nikkor lenses on Digital Nikons

Using old Nikkor lenses on Digital Nikons

Written by David Barth, 3 December 2008.

The venerable Nikon single lens reflex (SLR) mount is legendary in that it has not changed since it was introduced in 1959 on the Nikon F, Nikon's first SLR camera.

Changes have been made over the years to the way the lens couples to the metering system on the camera body, and the initial discussion briefly describes the types of couplings used, because it is the lens characteristics and f-stop setting that need to be transmitted to the camera body to provide exposure control.

NON-AUTOMATIC INDEXING (NAI)

Non-Autofocus, Non-Automatic Indexing Lens
Non-Autofocus, Non-Automatic Indexing Lens.

This is a Non-Autofocus, Non-Automatic Indexing Lens. Note the fork that couples with a pin that protrudes from the bottom of a Photomic (metering) finder.

NIKON F AND NIKKORMAT CAMERAS

Nikon F Non-Automatic Indexing (NAI) meter pin
Nikon F Non-Automatic Indexing (NAI) meter pin.

This shows the Nikon F Non-Automatic Indexing (NAI) meter pin that couples to a fork on a lens. As the f-stop ring is rotated, the fork moves the pin to index the exposure meter to the f-stop setting on the lens.

The Nikon F, some F2, and most Nikkormat cameras, are Non-Automatic Indexing (NAI) cameras. They have a pin that couples to the lens f-stop (aperture selector) ring on the rear of the lens. The lens has a simple, metal fork that couples to a pin on the camera's light meter. This coupling allows the light meter to know the selected f-stop of the lens, and with the speed setting on the light meter, provides an exposure indication by way of a needle that can be seen in the viewfinder and on top of the camera.

In the case of the Nikon F, the top meter needle display window is on the top surface of the finder. On Nikkormat cameras, the window is on the top cap, to the left of the finder. As the f-stop ring on the lens is rotated, its coupling to the meter, via the pin on the finder, indicates the selected lens f-stop.

AUTOMATIC INDEXING (AI)
Nikon Automatic Indexing Lens (AI)
Nikon Automatic Indexing Lens (AI).

This is a Non-Autofocus, Automatic Indexing (AI) Lens. The AI feature is the raised rim on the back of the f-stop selector ring. Note that the fork allows the lens to be used with NAI cameras.

Nikon Automatic Indexing Lens (AI)
Nikon Automatic Indexing Lens (AI).

This is another view of the Non-Autofocus, Automatic Indexing (AI) rim.

During the early 1970s Nikon developed "automatic indexing" (AI) which changed the way the lens transmitted f-stop settings to the camera body. This feature was applied to later Nikon F2 cameras (the early F2 cameras used the NAI pin) as well as the Nikkormat FT3, ELW, and EL2 camera bodies. The design eliminated the pin that protruded from the finder, changing to a tab that moved around the lens mount. Instead of using the fork on the lens, a rim on the back of the f-stop ring coupled the f-stop setting of the lens to the camera's meter through a tab that rotated around the lens mount. AI lenses of this era, throughout the 1970s and into the 1980s, retained the fork to allow backward compatiblity to the earlier, NAI cameras.

In 1980, when the Nikon F3 was introduced, the fork could reduce light entering the finder to illuminated the f-stop setting of the lens. This problem was reduced by punching holes in either side of the fork's slot to allow more light to enter the F3 f-stop indicator.

During the late 1980s, the fork on lenses was discontinued, but a small impression or dimple on the f-stop ring of the lens indicates where one of the fork mounting holes can be drilled to attach a fork. It is not known how long Nikon provided replacement forks and screws, but I had a supply of aftermarket forks manufactured by a machine shop. The screws used on forks from 1959 through the early 1960s were slotted, but they are very rare.

Note that most older, Non-AI lenses can be modified to AI by a camera repair person who can trim the rear of the f-stop ring so that a rim allows connection to the AI tab on the camera. However, the value of old lenses may drop if they are modified because they become less desirable to collectors. Original, non-AI lenses are becoming rare and should be left unmodified. It is better to simply purchase the same lens made for AI at the factory.

An NAI lens should never be mounted on an AI camera body that has the tab because the rim of most lenses will interfere with the tab, binding the f-stop ring.

AUTOFOCUS (AF) LENSES

Nikon Autofocus Automatic Indexing Lens (AI)
Nikon Autofocus (AF), Automatic Indexing (AI) Lens.

This is an Autofocus, Automatic Indexing Lens. Note that AF lenses have pins on the back that transfer electrical signals between the camera body and the lens.

Nikon Autofocus Automatic Indexing Lens (AI)
Nikon Autofocus (AF), Automatic Indexing (AI) Lens.

This is an Autofocus, Automatic Indexing Lens with the indentation for attaching an old-style, non-automatic indexing (NAI) fork.

G-TYPE LENSES
In the late 1990s, Nikon introduced "G" lenses that did not have an f-stop ring. Instead, the lens had a small computer chip that indicated the internal f-stop through electrical contacts on the rear of the lens. These lenses can be mounted to older cameras, but there is no transmission of the f-stop setting to the camera. G lenses are autofocus. Nikon continued to manufacture lenses with AI rims to enable backward compatibility to older cameras.

AF-S LENSES
Nikon Autofocus Automatic Indexing Lens (AI)
Nikon Autofocus (AF), Automatic Indexing (AI) Lens.

This is a Silent Wave Autofocus (AF-S), Automatic Indexing Lens.

Nikon Autofocus Automatic Indexing Lens (AI)
Nikon Autofocus (AF), Automatic Indexing (AI) Lens.

This is a Silent Wave, Autofocus, Automatic Indexing Lens with an indentation or dimple for attaching the old-style fork. Original AF Nikon lenses used a motor inside the camera body coupled to the lens to focus it. AF-S lenses have a motor inside the lens that focuses it. Focus information is transmitted from the camera body to the AF-S lens through electrical contacts.

AF-S lenses are autofocus, as the "AF" indicates, and automatic focusing is accomplished through a focusing motor inside the lens, indicated by the "S." These lenses are similar to G lenses except that they often have the f-stop ring and rim.

NIKON DIGITAL CAMERAS: D100, D70, D70S
Nikon D100 Digital Camera
Nikon D100 Digital Camera.

This is a Nikon D100 Camera. Note that it does not have the automatic indexing (AI) tab. Non-autofocus AI lenses can be used with the camera in manual mode.

The first Nikon Digital camera, the D1, was introduced in the 1999, continuing with the lens mount as it was in 1959. The D100, D70, and D70S bodies did not have an AI tab on the side of the lens mount, so they could not meter with lenses that do not have a computer chip inside. These cameras had to be operated in manual mode where the f-stop and speed setting is manually entered into the camera. The advantage of digital cameras is that the result of an exposure can be viewed immediately, and the f-stop and/or speed could be adjusted if the exposure was not correct. An external light meter could be helpful. I have shot many photos through old, 1960s-era lenses mounted on a D100 digital Nikon with excellent results.

THE NIKON D200
Nikon D200 Digital Camera
Nikon D200 Digital Camera.

This is a Nikon D200 Camera with the AI tab.

Nikon D200 Digital Camera
Nikon D200 Digital Camera.

This is a Nikon D200 Camera with the AI tab.

The Nikon D200 has the AI tab beside the lens mount, allowing AI lenses to meter. The D200 also allows lens characteristics, such as minimum f-stop, to be entered into the camera to aid in the use of older lenses. Most Non-AI lenses cannot be mounted on the D200 because the AI tab conflicts with the f-stop ring on the lens.