APO EL Nikkor 105mm F5.6N   3
APO EL Nikkor 105mm F5.6N     3

APO EL Nikkor 105mm F5.6N

APO EL Nikkor Technology

The unexcelled quality of Nikon-built cameras and lenses has greatly contributed to the widespread use of 35mm format photography. Quite naturally, Nikon has responded to the needs of the film processor as well. In ordinary photoengraving lenses, 1 : 1 is the standard magnification. But when used to produce large images, such as in the step and repeat method, a truly sharp image was difficult to obtain.

To reproduce images as much as ten times the size of the original requires lenses designed for high magnification work with the aberrations fully corrected over the entire range. Apo-EL-Nikkor Lenses have been designed with standard magnifications of 2X (170mm), 5X (210mm and 480mm) and 10X (105mm and 300mm) to provide a wider range of application. Working in such a powerful magnification range opens the possibility for a host of problems due to insufficiencies in the reproducing lens.

Apo-EL-Nikkor Lenses surpass this challenge with highly effective aberration correction and extremely sharp resolving power. These lenses are designed exclusively to provide superior performance when making critical photo enlargements or exacting color separations from small original film formats. Optimum performance is available not only at the standard magnifications but is maintained throughout the entire range. Apo-EL-Nikkor Lenses are available in five focal lengths for various sized originals.

Full spectrum resolution

In order to make color enlargements from a color original, the original must be color separated into three elements - red, green and blue. Up till now, apochromatic lenses like Apo-Nikkor lenses with chromatic aberration corrected for three colors have been used for processing. However, in the combined enlargement/color separation process with small originals, even a minute detect in the lens in magnified enormously, since these lenses are originally designed for use at around 1 : 1 magnification.

Apo-EL-Nikkor lenses are designed for color separation work involving high magnification and, through a combination of special Nikon-produced optical glasses and an ingenious optical design, chromatic aberration is corrected not only for the three primary colors, but for the entire visible range of the spectrum. Moreover, Apo-EL-Nikkor lenses are corrected for chromatic aberration in the near ultraviolet and near infrared ranges since the spectrum sensitivity of film emulsions is not always identical to that of the human eye. These lenses provide an extra margin of fidelity resulting in more accurately reproduced color and richer tone.

The outstanding resolution, higher than that of any existing original film, is because nearly perfect elimination of all other aberrations is as well made possible by limiting the picture angle of the lenses. Consequently, there is no significant image displacement or difference in image size, regardless of magnification.

Full aperture brightness

The optimum performance of Apo-EL-Nikkor lens is designed to be obtained at their full aperture of f/5.6. The maximum aperture of f/5.6 provides plenty of light for processing work despite the usual insufficiency of light inherent in making enlargements, thus saving exposure time. Furthermore, light transmission at the circumference of the lens is as good as that at the center, and off-axis light fall-off is minimized.

Nikon Integrated Coating (NIC)

As further insurance for accurate reproduction, a multi-layer coating is applied to glass-to-air surfaces whenever needed. The occurrence of internal reflection is virtually eliminated and thus images remain sharp, clear, and contrasty over the entire picture area.

This additional feature of Apo-EL-Nikkor lenses offers the extra measure of performance necessary in performing demanding photo enlargements and color separation work.

  LENS and APERTURE   FILM SIZE
  APO EL 105mm    F5.6   24 x 36 mm
  APO EL 105mm    F8   56 x 56 mm
  APO EL 210mm    F5.6   56 x 56 mm,  24 x 36 mm
  APO EL 210mm    F8   90 x 120mm  (4 x 5 inch)

Mounting the lens on a process camera

Enlarger-type process camera:  Attach the lens in the usual way with its rear mount facing the camera. The Apo-EL-Nikkor 210mm f/5.6, 300mm f/5.6 and 480mm f.5.6 lenses are supplied with a flange to facilitate attachment to the camera using nuts and bolts.

Darkroom process camera:  All lenses can be attached with the front mount facing the camera. Remove the ornamental front ring (for the 170mm lens, this is not necessary) and screw the lens into the process camera. A flange can be attached to the front mount of the Apo-EL-Nikkor 210mm f/5.6, 300mm f/5.6 and 480mm f.5.6 lenses. The Apo-EL-Nikkor 170mm f/5.6 requires an intermediate ring of 52mm attachment size for mounting.

Referenced the following material;
Nikon Apo-EL-Nikkor Lenses
for color separating/screening/enlarging
Nippon Kogaku K. K.

Specifications

The old type of lens and the new type of lens exist in APO EL Nikkor 105mm F5.6 lens. The APO EL Nikkor 105mm F5.6N lens introduced in this article is the new type of lens.

(1) Old type of Lens

APO EL Nikkor 105mm F5.6

Focal length :  105 mm
Maximum aperture ratio :  1:5.6
Minimum f/stop :  f/45
Aperture scale :  1/3 step
Lens construction :  8 elements in 4 groups
Standard magnification :  10 X
Usable magnification range :  5 - 20 X
Picture angle :  40°
Corrected chromatic aberration range :  380 - 700 nm
Vignetting :  0% (at f/8)
Distortion :  +0.06%
Size of originals :  80 mm⌀
Image distance at standard magnification :  1265.6 mm
Filter size :  d=40.5 mm p=0.5 mm
Mount :  Leica L39 screw mount
Length :  60 mm
Diameter :  51 mm
Weight :  315 g

Release date :  Jun 1971
Price :
  207,000 Japanese YEN (1974)
  207,000 Japanese YEN (1976)
  207,000 Japanese YEN (1977)

(2) New type of Lens

APO EL Nikkor 105mm F5.6N

Focal length :  104.8 mm
Maximum aperture ratio :  1:5.6
Minimum f/stop :  f/32
Aperture scale :  1/3 step
Lens construction :  8 elements in 4 groups
Standard magnification :  10 X
Usable magnification range :  5 - 20 X
Picture angle :  47°
Corrected chromatic aberration range :  380 - 750 nm
Vignetting :  0% (at f/8)
Distortion :  -0.07%
Size of original :  80 mm⌀ (at f/5.6)
Size of original :  100 mm⌀ (at f/8)
Image distance at standard magnification :  1265.3 mm
Filter size :  d=35.5 mm p=0.5 mm
Mount :  Leica L39 screw mount
Length :  49 mm
Diameter :  45.5 mm
Weight :  140 g
Actual weight :  139.5 g

Release date :  1980
Price :
  207,000 Japanese YEN (1982)
  207,000 Japanese YEN (1984)
  207,000 Japanese YEN (1985)
  207,000 Japanese YEN (1987)

APO EL Nikkor 105mm F5.6N Lens Construction

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Chapter 1      Encounter with the Lens
Chapter 2      Nikon Z Album
Chapter 3      APO EL Nikkor Technology
Chapter 4      Collector's Guide
Chapter 5      APO EL Nikkor Gallery

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