Nikon’s Roots Vol. 06 – Nikkorex Zoom 35

What is the Nikkorex Zoom 35?

Lens shutter camera with fixed zoom lens

The Nikkorex Zoom 35, released in 1963, was a Nikkorex 35II body with a 43-86mm F3.5 zoom lens fixed to it. In later years, it became common to attach a zoom lens to a lens-shutter camera after the Pentax Zoom 70 in 1986, but this camera had set this bar more than 20 years earlier.

Zoom lens for still cameras

Zoom lenses have a long history, appearing in the 1930s as lenses for movie cameras. Although it had been developed for a while as a video camera, it was only after the practical use of single-lens reflex cameras that it began to be used for still cameras. In 1959, when the Nikon F was released, the Nikkor Auto Telephoto Zoom 85-250mm F4-4.5 was released as an interchangeable lens, and in 1961, the Nikkor Auto Telephoto Zoom 200-600mm F9.5-10.5 was released.

The appeal of zoom lenses is that you can enjoy a variety of focal lengths with a single lens without having to change lenses, and a single-lens reflex camera is the perfect camera to take advantage of this, but even a single-lens reflex wide-angle lens for a single-lens reflex camera is only 28mm. The optical design technology of the time made it difficult to create zoom lenses with short focal lengths, and lenses were inevitably limited to telephoto focal lengths.

Voigtlander zoomer

Nevertheless, attempts were made to create zoom lenses for still cameras in the range from standard lenses to wide-angle lenses. The earliest example was the 1960 Voigtlander Zoomer 36-82mm F2.8. This lens was released as an interchangeable lens for Besamatic, a lens-shutter SLR camera made by West German Voigtlander, but its specifications were quite unreasonable, and due to the limitations of the lens-shutter SLR mount, its rendering performance was beyond practical. It is said that it was so bad that he doubted it.

It’s not hard to imagine that the zoom lens of the Nikkorex Zoom 35 was also inspired by this Voigtlander zoomer. Naturally, Nikon also continued to take on the challenge of creating a standard zoom. In fact, before Nikkorex Zoom 35, they had developed a standard zoom lens called Auto Nikkor Wide Zoom 3.5-8.5cm F2.8-4 . Unfortunately, this lens was discontinued just before mass production. The main reason seems to be that the filter diameter was 86mm, which was large and heavy at the time. Considering that interchangeable lenses are getting quite large these days, it’s a normal size…

Therefore, the Nikkorex Zoom 35’s 43-86mm F3.5 zoom lens is Nikon’s second attempt at a standard zoom. Based on my experience with the 3.5-8.5cm F2.8-4, I kept the size and weight to a reasonable level. The reason why the brightness was set at F3.5 instead of aiming for F2.8, and the focal length at the wide end was a slightly odd value of 43mm, was probably due to the intention of prioritizing miniaturization.

Is the F value constant or F value variable?

Many of today’s zoom lenses have F-numbers that change when zooming. The diagram shows that there are some high-end lenses whose F value does not change. In the early days of zoom lenses for still cameras, like the telephoto zoom mentioned above, there were lenses with variable F-numbers, but lenses with a constant F-number soon became mainstream. Even if it does change, the amount of change is small, and with Nikon’s 85-250mm, etc., the change only occurs near the aperture, and at apertures smaller than F4.5, the setting value remains unchanged.

This is related to the exposure control conditions at the time. Even if the F value of the lens changes when zooming, TTL metering will automatically correct it, but TTL metering had not yet appeared in this era, and even if the camera had a built-in exposure meter, It either read the indicated aperture value and set it on the lens side, or it was linked using a fixed point type or tracking type. In any case, it is an external light type. When shooting with such a camera, you aim at the subject while looking through the viewfinder, and when you zoom and change the focal length, the aperture value also changes, so you have to take your eyes off the viewfinder each time to correct the aperture value that has shifted. I have to do this, and it’s a hassle.

The External Light Meter

The Nikkorex Zoom 35 also has an external light meter. Therefore, the lens had to be able to maintain its aperture of F3.5 even when zooming. However, it was not possible to achieve this with an optical lens configuration, and it appears that the aperture was moved in conjunction with zooming. This camera was featured in the April 1963 issue of Asahi Camera magazine in the “New Face Diagnosis Room,” and as a result of actually measuring the brightness of the lens, it was found to be F3.1 at the wide end and F3.52 at the tele end. It has been pointed out.

In response, Nikon’s response was, “Maybe the results were measured with the lens removed.” In other words, when attached to the body, the aperture is mechanically corrected so that the open F value remains constant at F3.5 in any case, but since it was removed from the body, that mechanism no longer worked. That’s what it means.

Interchangeable lens for Nikon F

The 43-86mm F3.5 standard zoom lens designed for the Nikon Rex Zoom 35 was also released as an interchangeable lens for the Nikon F. As far as I can confirm from the configuration diagrams of both, the optical systems seem to be the same. However, the one for Nikkorex Zoom 35 has a “rotating zoom” with separate focusing ring and zoom ring, whereas the one for Nikon F has the same ring moving straight for zooming and rotating it for focusing. , it has been changed to so-called “straight zoom”.

The Nikkorex Zoom 35 itself was not very impressive, partly because it was large for a lens-shutter camera, but its intended concept of a practical standard zoom was realized as an F-mount interchangeable lens, and it was well received by users.

Further Zoom Lenses for Nikon F cameras

By the way, I have been wondering about this lens for the Nikon F for some time now, as to when it will be released. According to Nikon’s company history, the Zoom Nikkor Auto 43-86mm F3.5 for Nikon F was released in January 1963. The Nikkorex Zoom 35 has the same date of February 1963. In other words, it is written as if the interchangeable lens for F was ahead of the other. However, the aforementioned Asahi Camera magazine’s “New Face Diagnostic Office” states, “It seems that this lens will be released separately for the Nikon F…”

In other words, when the Nikkorex Zoom 35 was released and tested, it seems that interchangeable lenses for the Nikon F had not yet been released, and I myself remember that the lenses for the F came later. There is. In addition, the September 1963 issue of the photo industry magazine had a special article titled “Japanese 35mm single-lens reflex camera technical data,” and in the Nikon F and Nikkorex F section there was an interchangeable lens called “Zoom Nikkor Auto 43-86mm F3.5.” is listed, but it is accompanied by a note that says “Price not yet determined.” It seems to be true that the interchangeable lenses for the F were released much later.