August 2025, Nikon Kenkyukai 3

August 2025, Nikon Kenkyukai 3

Auto NIKKOR Telephoto-Zoom 8.5-25cm f/4-4.5

Nippon Kogaku's Masterpiece

Auto NIKKOR Telephoto-Zoom 8.5-25cm f/4-4.5
With Nikon F brochure

Auto NIKKOR Telephoto-Zoom 8.5-25cm f/4-4.5
A perfect fit for the Nikon Z 9

The Nikon Z 9 looks great with a vintage zoom lens

f=8.5cm

Lens Hood with Engraved Nippon Kogaku Mark

Early and Late Models

f=25cm

Summer Study Session

It was a very quiet summer afternoon in Kyobashi Tokyo. A PowerPoint slide was projected, and the explanation began. We researched and studied the Auto NIKKOR Telephoto-Zoom 8.5-25cm f/4-4.5 lens.

Summer Study Session

Here is the PowerPoint content (PDF) : A Pioneer in Zoom Lenses for Still Cameras

Black Nikon

A cool camera was on stage. This is a Nikon F with a black body. The mounted lens is a Nikkor 20mm F4 with a Nikon HK-3 hood. The view is beautiful with the Nikkor 5.8cm F1.4 lens nearby.

Black Nikon

NIKKOR 20mm F4

NIKKOR 5.8cm F1.4

The NIKKOR 5.8cm F1.4 lens looks great with a dedicated hood engraving the Nippon Kogaku mark. It also comes with a rare factory-use lens rear cap.

Keep an eye on the serial number

Aero-Nikkor

Aero-Nikkor is Here

Aero-Nikkor 20cm F3.5 No. 38317339

Aero-Nikkor 20cm F3.5

This historic large aperture lens (F3.5) lens is for reconnaissance use with small aerial cameras (SK-100) of the former Imperial Japanese Army Air Force. It is said that there are only about 10 of these left.

Technical Specifications

Primary specifications: 3-stop aperture system (F3.5/4/5.6) with stopper release allowing beyond F5.6 (no indicators)
Construction: Brass unit with aluminum exterior for lightweight design

SK-100 Camera System

The majority of SK-100 cameras were equipped with Konishiroku Hexar lenses (20cm F3.5, 40cm F5.6)
Aero-Nikkor equipped units were in minority

As a collector's note, I would like to show you how many of these lenses exist. Dr. Dirk Spennemann compiled this list, which is presented below with his permission.

Aero-Nikkor 20cm F3.5 Serial Number List

38317 16
38317 142
38317 173
38317 246
38317 249
38317 326
38317 339
38317 412
38317 420
38317 436
38317 452
38317 453

Permission to publish is approved by Dr. Dirk Spennemann, 2025.

I received explanatory comments from Dr. Dirk Spennemann, which we would like to introduce below. He is not only a university professor but also a devoted collector of Rokuoh-sha and Konishiroku.

To meet the high demand the Imperial Japanese Army had for the Konishiroku-designed SK-100 aerial reconnaissance camera, Konishiroku was required to outsource some of the production of the camera bodies to Katsura Seisakusho and Chiyoda Kogaku.

To satisfy the demand for the additional 20cm lenses that were required, Konishiroku had to offer the lens designs to other manufacturers, who were required (by the Japanese Army) to manufature these.

Therefore some of the 20cm lens production was handled by Tokyo Kogaku (Simlar f3.5), by Takatiho Kogaku (Zuiko f3.5) and by Nippon Kogaku (the Aero-Nikkor).

The lens shortage was such that even Zeiss Tessar lenses had to be adapted. The Nikon Aero-Nikkor is a really rare lens, suggesting that overall involvement in the production was only small. As far as is known, Nippon Kogaku did not manufacture SK-100 camera bodies.

Dr. Dirk Spennemann
Charles Sturt University, Albury, Australia

Aero-Nikkor 20cm F3.5 No. 38317339

Aero-Nikkor Lens and Nikon Cameras

Aero Nikkor and its Scenery

Nikon F2 Wimbledon Special

The Nikon F2 Photomic AS (DP-12) Spot-metering and Latched Green LED Light Modification

The Nikon F2 Photomic AS (DP-12) originally features TTL center-weighted full-aperture metering, but this unit has been modified to narrow the photosensitive area of the SPD metering system, converting it to central spot metering. Additionally, while the original viewfinder illuminator on the DP-12 turns off when you release the switch, this unit has been converted and modified to a green LED specification that remains illuminated until the power is turned off (by returning the film advance lever), making it convenient for night photography.

This modification was performed by a Nikon F2 repair specialist Sover Wong residing in the UK at the request of a British professional sports photographer Tony O'Brien who, while primarily shooting soccer and tennis professionally, wanted more precise exposure control for his hobby photography using 35mm reversal film. Only 6 cameras worldwide are known to exist with this type of modification.

Tony O'Brien's website, a British professional sports photographer
tony o'brien
https://tonyobrienphotography.co.uk/

From the website of Sober Wong, who carried out the modification
Modified DP-12 with spot metering for Tony O'Brien
https://soverf2repair.com/DP-12_spot_metering.html

Specialist Nikon F2 Repair & Restore Services (HP)
https://soverf2repair.com/

Special Spot Metering Model

Beautiful Green LED Light

Tony O'Brien uses the latest Nikon digital cameras to photograph on football stadiums and tennis courts. However, after a hard day's photography, he picked up an old Nikon F2 film camera.

With this special Nikon F2, he further refined his expressive powers and sensitivity as a photographer in areas such as contrast and shadow, and he was able to put these insights to good use in his next digital shoot, demonstrating their effectiveness.

Sover Wong kindly provided us with images of the modifications to this Nikon F2, and we have included two of them below.

Standard Nikon

F2 Titan

Standard F3

Nikon F2 High Speed Motor Drive Camera

F2H

Noct NIKKOR 58mm F1.2

Nikon MD-100

F2 TITAN USERS SOCIAL CLUB
NIKON KENKYUKAI TOKYO

Nikon F2 High Speed Motor Drive Camera

H-MD

Shu Akayama Channel Part 3

A professional photographer Shu Akayama introduced the Nikon Kenkyukai Tokyo on his YouTube show.
Released on August 20, 2025
https://www.youtube.com/watch?v=sQ3bVutzYKM&t=107s

The Nikon Kenkyukai Tokyo Meeting
Part 3 Nippon Kogaku's Masterpieces

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