NIKKOR - The Thousand and One Nights No.48
The Nikkor-Q Auto 200mm f/4
Tale 48 introduces the Nikkor-Q Auto 200mm f/4 lens, the first true telephoto F-mount lens.
by Kouichi Ohshita
I. A Product of SLR Cameras
Telephoto lenses are the products of SLR cameras.
Up until the 1950s, telephoto photography was the primary weakness of rangefinder cameras, the mainstream 35-mm camera of the time. As the shooting lens and viewfinder were separate with these cameras, there was no way to avoid parallax errors (when the view through the viewfinder differs from the shooting area captured by the lens) with shooting at close distances. Even with rangefinder cameras that provided adequate focusing accuracy in the normal range, this accuracy gradually suffered as focal length increased. Rangefinder cameras were barely able to maintain adequate focusing precision at focal lengths of up to 100 to 135mm.
While single-lens reflex cameras overcame this weakness of rangefinder cameras, the first SLRs had serious faults of their own. Chief among these were the waist-level finder with which left-to-right reversal of the image darkened with shooting and manual operation of the aperture. Just as with twin-lens reflex cameras, the first single-lens reflex cameras used waist-level finders that simply had a focusing screen positioned above the main mirror. Light passing through the shooting lens was reflected upward at a right angle from the main mirror to the focusing screen. This made photographing moving subjects more difficult than with rangefinder cameras utilizing eye-level viewfinders, which enabled upright, laterally correct images. Moreover, the main mirror was raised with shooting and remained up until the film was wound and the shutter charged. In addition, the aperture was operated manually.
The shooting lens aperture was not a major concern with rangefinder cameras where the shooting lens and viewfinder were separate. However, as the shooting lens also served as the viewfinder on SLR cameras, darkening of the viewfinder display when the aperture was stopped down was a drawback. Not only did the viewfinder display become dark, but focusing became more difficult as the aperture was stopped down. This meant that photographers had to first open the aperture all the way, focus, and then manually stop down the aperture to the desired setting prior to shooting.
In short, it took much longer to set up each shot with the first SLR cameras than it did with rangefinder cameras.
Later, SLRs were equipped with penta-dach prisms, eye-level viewfinders rather than waist-level finders, and quick-return mirror mechanisms. This decreased viewfinder blackout time and enabled automatic aperture linked to shutter release so that the photographer no longer had to adjust the aperture manually. These modifications led to the SLR cameras commonly used today with their simple operation and ability to respond immediately to almost any photo opportunity. The Nikon F, released in 1959, was an SLR camera developed to offer all of these features. It also enabled telephoto shooting at focal lengths greater than 135mm with operation similar to that of the Nikon S. To say that the Nikon F was created specifically for the Nikkor-Q Auto 200mm f/4 really wouldn't be an exaggeration.
II. The Nikkor-Q Auto 200mm f/4
Released in 1961 as the tenth Nikon F-mount lens, the Nikkor-Q Auto 200mm f/4 was the first 200-mm full-scale telephoto lens to be equipped with a fully automatic aperture mechanism.
Younger generations unaware of the technologies and capabilities of the time will likely wonder, then, why F-mount lenses, including this lens, sold before the release of Ai Nikkor F-mount lenses all used "Nikkor Auto" in their names. It was because these lenses utilized fully automatic apertures. With lenses named "Nikkor Auto", the aperture was opened fully prior to shutter release, stopped down just as the shutter was released, and then automatically restored to maximum aperture after the image was captured.
At that time, Nikon was developing not only dedicated F-mount lenses, but also lenses that could be used with both the Nikon S and F cameras. These lenses, however, were not equipped with the automatic aperture mechanism. The Nikkor-Q Auto 200mm f/4 was developed by Masaki Isshiki. He began working at Nikon in 1949, one year after Zenji Wakimoto, and with the quick introduction of hastily developed electronic computers to the lens design process, is recognized as having established the computer-aided lens design system. The basic design was completed in July 1960, and after verification of performance through trial production, the lens was released in July 1961. As shown in Illustration 1, the lens was a simple structure of four elements in four groups. The front lens group (first and second groups) and rear lens group (third and fourth groups) were each comprised of one convex and one concave element, making it a telephoto type lens. The full optical length (length from the edge of the first lens element to the focal plane) is slightly shorter than the focal length because the entire rear lens group offers concave lens features.
As the rear lens group acts as a teleconverter and pincushion distortion is common with telephoto lenses, axial chromatic aberration can be problematic. However, by not shortening the length of the lens too much and by utilizing a convex lens for the third element, adequate compensation for this aberration is provided. This lens truly shows the advantages of a simple structure of four elements in four groups.
What is the Nikkor-Q
I'd like to take this opportunity to offer a simple explanation of the meaning of names such as Nikkor-Q and Nikkor-P attached to old lenses. As some may likely guess, the letters such as "Q" or "P" indicate the number of lens elements.
Specifically, names with "T" have three lens elements, "Q" have four, "P" have five, "H" have six, "S" have seven, "O" have eight, and "N" have nine.
The most likely reason that this naming method was abandoned was that later lenses utilized so many more individual lens elements. This method was used up until the Nikkor-UD Auto 20mm f/3.5, which had 11 lens elements, but just how would a lens like the AF-S 200-400mm with its 24 lens elements have been named using that same method had it existed at the time? Although this method is no longer used in the naming of lenses, it would be useful in distinguishing changes in lens type, such as occurred with the original Nikkor-S Auto 5cm f/2 and the modified Nikkor-H Auto 50mm f/2.
III. Design improvements
A couple of years after its initial release, the Nikkor-Q Auto 200mm f/4 underwent some minor modifications. These modifications enabled support for the color film that had just started to become common. Initially, only glass with an unexpectedly high blue transmissivity was used with the Nikkor-Q Auto 200mm f/4. Therefore, users complained that images captured with this lens were somewhat bluer than those taken with other lenses. With the need to change the materials used for the glass in order to correct colors, Nikon designers took the opportunity to make other improvements without changing the basic lens type.
Yoshiyuki Shimizu took over design from Isshiki, managing to increase sharpness by correcting spherical aberration, and to increase performance further. Functionality was also increased with structural modifications that enabled a reduction of the closest focusing distance from three meters to two, adoption of a seven-blade iris diaphragm to replace the earlier six-blade component, as well as reducing minimum aperture from f/22 to f/32.
The original models and the modified models could be differentiated by their closest focusing distance, minimum aperture, and name plates. The name plates on which focal length and such were imprinted were silver on original models, but had a black finish on modified models.
IV. Lens rendering
Now let's look at lens rendering. The lens used to capture the sample shots was a modified Nikkor-Q Auto 200mm f/4 with multi-layer coating applied. The camera used was the D700 digital SLR. The first image, Example 1, is a distant landscape shot captured at maximum aperture. As you can see, rendering appears uniform throughout the frame at maximum aperture. If we enlarge the image so that we can see each individual pixel, some blue to purple flare is visible at the edges of the sky, but as it is very weak, it is only noticeable in highly contrasting portions. This is not the result of axial or lateral chromatic aberration, but rather color coma flare. Therefore, stopping down the aperture significantly reduces the problem.
Example 2 is a photo of a building captured with the aperture stopped down to f/8 in order to enable as deep a depth of field as possible. At an aperture setting of f/8, the blue flare mentioned above is reduced to the point that it is almost non-existent. In addition, there is very little distortion, a characteristic that must be mentioned when discussing this lens. While it is very difficult to compensate for pincushion distortion with telephoto lenses, it has been corrected to the point that it is completely unnoticeable with this lens. This makes the lens a great tool for capturing images of subjects with straight lines, such as buildings or trains.
Examples 3 and 4 are images of flowers captured at maximum aperture. Example 3 is a photo of flowers taken at a certain distance, and Example 4 is a close-up shot of lotus flowers. The flowers, which are the primary subjects, are clearly rendered, and the blurring of the background in both images is gentle and beautiful. This is most likely due to correction of aspherical aberration applied with the modified design. As the subjects differ, direct comparison is not really possible, but I think you will see how the flower photos captured with this lens differ from the sample photo of camellia flowers in Tale 46 in terms of rendering and blur characteristics.
The Nikkor-Q Auto 200mm f/4 was an instant best seller used by a wide variety of photographers for press and sports coverage, landscapes, railroads, astronomy, and so on because it offered the high performance and nimble operation designers intended. It was sold for 15 years, during which time it remained a favorite of a great many photographers, until the release of the Nikkor 200mm f/4 in 1976 with completely new optics and a more compact size. I believe that this is a lens that many long-time Nikon fans remember fondly and with which they captured great masterpieces.
In addition, the fact that using this lens with the Nikon F made the telephoto shooting that had previously been so difficult so much easier certainly changed the way in which photographers took pictures, and probably served as a driving force behind the popularization of SLR cameras. Working off the success of this lens, Nikon would later develop a whole lineup of telephoto lenses, releasing 300-mm, 400-mm and 600-mm lenses one after the other. The age of the telephoto lens, ignited by the 1964 Tokyo Olympics, began with the Nikkor-Q Auto 200mm f/4.
NIKKOR - The Thousand and One Nights
The history of Nikon cameras is also that of NIKKOR lenses. This serial story features fascinating tales of lens design and manufacture.