NIKKOR - The Thousand and One Nights No.19
Nikkor-S·C 8.5cm F1.5
This tale nineteen brings up Nikkor lens for a rangefinder Nikon S-type camera for the first time in some quite years. This lens was an origin of Nikon first medium telephoto lenses. Tonight, I will introduce to you a history of a time-proven portrait lens that seniors dedicated themselves to and its image characteristics.
by Haruo Sato
I. Mr. KIMURA, Ihei's "right-hand man"
There were two photographers that twinkled like shooting stars and lived actively in Showa era. These two stars are Mr. DOMON, Ken and Mr. KIMURA, Ihei who are acknowledged masters of photography everybody knows very well. Mr. Domon, who pursued sharpness and documentary spirit, loved and used habitually Nikkor lenses from a 35mm format lens to a large format lens, whereas Mr. Kimura expressing humanity and flavour of life was famous as a Lica whiz.
Both of the masters were reputed to be known as "Mr. Domon photographed a manly and powerful picture, whereas Mr. Kimura took a womanly and chic photograph". A Lens that was a long cherished favorite item of Mr. Domon and Mr. Kimura over their lifetimes and produced lots of masterpieces was, in fact, Nikkor 8.5cm f/1.5. The myth, just like Litze lens was best suited for portraiture, but Nikkor lens was too solid to be suitable for portraiture, was squashed completely by both masters.
II. Chronicle of lens development
Now let's take a close look at a chronicle history of a Nikkor lens 8.5cm f/1.5 development. Mr. MURAKAMI, Saburo, who appeared in tale seven (7) section, was the first to start an optical designing. A first trial blueprint was drawn on July of 1950. From the beginning, an optical system of Nikkor lens 8.5cm f/1.5 was a typical Sonnar type consisting of two pairs of a three-element cemented lens. Afterward, the optical designing was succeeded by Mr. WAKIMOTO, Zenji who was introduced in the tale one (1) section and further aberration corrections were improved. According to a record, drawings were written 8 times from 1950 to 1952.
The record says that there were produced seven kinds of working trial lenses with a different optical system. Surprisingly, among the seven working trial lenses, there were manufactured working lenses based upon daring design plans using an optical system of f/1.4 or a 4-element cemented lens. Optical designers in those days repeated lots of trial products. It should be said that they might have made huge amounts of aberration measurements and taken lots of actual shots repeatedly. And then with a two-year developing period, this time-proven portrait lens was debuted. Wakimoto-san must have worked hard with difficulty, especially, this time. If he were alive, we could surely hear interesting hard luck stories from him.
III. Image characteristics and lens performance
Let's look at a sectional view. You would notice how similar this lens looks to Nikkor lens 5cm f/1.4. You can see at a first glance that this lens is a typical Sonnar type. A key point of characteristics of the Sonnar type is a power arrangement of the lens. The power arrangement of the Sonnar type is a telephoto type. As far as a construction of this lens is concerned, a large angle of view cannot be obtained, but a fast lens of a relatively small size is feasible.
More specifically, regardless of makers here and there, 85mm f/1.4 for 35mm SLRs employs a Gauss type as a basic lens construction. Thus, the Gauss-type lens realizes a higher performance than the Sonnar-type lens. But, it is inevitable that an employment of the Gauss type leads to a larger lens size. This difference is a very proof of " A basic lens character is determined by a lens type". The Sonnar type has a characteristic that aberration fluctuation at a close range is large. Namely, the closer the lens is focused to the closest focus distance, the softer the subject image becomes and flare is increasing. It can be said that the characteristic of this seemingly shortcoming is well suited for portraiture or photography of a fixed still subject and the lens delivers an exquisite imaging characteristics.
By the way, how does an end result photo actually taken with Nikkor 8.5cm f/1.5 look like ? Let's look at a sample picture from a viewpoint of aberration characteristics and a result of the actually taken sample. So, please be patient to spare a couple of times although a difficult explanation is on a little bit.
An aberration characteristic of this lens is, first of all, spherical aberration. As a lens designing technique, a biggest characteristic is that a stopper plane (a plane of strong curvature in a three-element cemented lens) of a lens in a rear lens group is used. This stopper plane produces a negative high order spherical aberration. By this action, excessively occurred flare is cancelled out. It is a very way of aberration correction, as if "Like cures like". This correction way gives a great effect to defocus characteristics. "Good taste" or "poor taste" correction depends upon an optical designer's skill. A second characteristic is a state of correcting astigmatism. Astigmatism is designed to get reduced at a shooting distance range of portraiture.
Also, another characteristic is that, on stopping down to f/2~f/2.8 only, flare gets disappeared and sharpness is enhanced. If further stopping down the lens to f/5.6~f/8, the lens renders a sharp and high contrast image characteristic peculiar to the Sonnar type. At a maximum aperture or its vicinity, portraiture is suitable and landscape photography is also suited on stopping down, in this way, the lens is of use just like "killing two birds with one stone".
Summing up the image characteristics of this lens, it can be said that "at a maximum aperture and its vicinity, the lens depicts an image characteristic of a mild and delicate line and a rich gradation and defocus characteristics can be expected. Only with two-stop down, flare gets cleared and the image characteristic changes to a sharp and comfortable contrast image characteristic. Further stopped down to f/5.6~f/8, the lens drastically turns its image characteristic into a high contrast and sharp image characteristic.
To tell the truth, I believed that this lens had the same image characteristic as Nikkor 5cm f/1.4 until a picture was actually taken and an analyzing work was started. That is, the lens at a maximum aperture has flare over the field like a veil, an image is varying from time to time as stopping down the lens, and then the image is being turned into a sharp image gradually. However, it is confirmed that aberration is superbly corrected and flare is conspicuous only when the lens is worked at a maximum aperture or its vicinity. Also, a result of a taken picture is fully satisfactory, too. I am really amazed to find that the optical designers at the time when even a calculator was not available had made outstanding aberration correction taking photographing method and defocus characteristics into consideration and at the same time, I really feel greatness of WAKIMOTO-san.
Now let's see and check the image characteristic using couple of sample pictures. Sample 1 is taken with a maximum aperture f/1.5 and a shooting distance of approx. 1.5m. You could see from the sample that it renders a moderate sense of resolution even in a rich and mild gradation and the blurred out-of-focus areas in front of and behind the focus point appears good, but as a contrast is relatively high and an amount of flare is quite delicate, its image characteristic looks very fine and pleasing. Sample 2 depicts an example for showing how defocus characteristics looks pleasing. Once you take a look at this sample, you could get a pleasing sense of defocus characteristics without lots of explanatory words.
Marumae-san on Nikon Station
At a forum at @nifty, there is a forum, named "SNIKON·Nikon Platz (Nikon station)" Nikon is pleased to present as a place to exchange information between customers. It has several conference rooms per each theme wherein members call them by a unique handle name. To begin with Dogu-san, ARI-san, ROCKE-san, many members have developed informative dialogues. In each conference room, there are many fan clubs and it is told that off-gatherings are often held. To be very honest, I wrote up this tale nineteenth section borrowing a lens from Marumae-san who is an active member of the Nikon Station. I have been anxious to get this lens for a long time, but the lens is quite expensive and its available quantity in the marketplace is very few, so I haven't got it so far. Just in the meanwhile, I get to know Marumae-san, which realizes the section this time.
What's more surprising, Marumae-san lended me this valued lens at a free-of-charge having faith in me even though he does not know anything about me. If it were not for Nikon Station, this tale nineteen section would be totally blank or not here.
Meeting members of SNIKON, I really felt that each member loves photography and a camera and has trust and expectation in Nikon. And also, I wonder how I can respond to their wishes, so I take seriously a responsibility and a duty as one of camera technicians. I would like to honor and respect this experience.