Tamron 400mm f/6.9 T-Mount (FO-69, 1963-1969)

Tamron 400mm f/6.9 T-Mount
(Mode# FO-69, 1963-1969)

2016.10.19 - Published

2022.08.07 - Re-written, re-uploaded photos

Tamron 400mm f/6.9

T-Mount (FO-69)

Model - FO-69

Years Produced - 1963-1969

System - T-Mount

Minimum Focusing - 9 meters

Focus Throw - 180 degrees

Aperture Range - f/6.9 to f/32

# Diaphragm Blades - 12

Filter Thread Ø - 62 mm

Optical Formula - 4 elements, 2 groups

Coating - Single coated (blue and purple sheen)

With built in rotatable tripod collar

Made in Japan

Versions of the 400mm T-Mount

Model# 340 (1960-1969)

400mm f/5.6 - 5el/4gr

https://www.tamron.co.jp/data/old-lens/olm400f5_6.htm

Model# 490 (1961-1969)

400mm f/7.5 - 4el/2gr

https://www.tamron.co.jp/data/old-lens/olm400f7_5.htm

Model# FO-69 (1963-1969)

400mm f/6.9 - 4el/2gr

https://www.tamron.co.jp/data/old-lens/olm400f6_9.htm

Model# ? (1963-1969)

400mm f/6.9 'Telescopic' - 4el/2gr

This lens can be detached into two halves

https://www.tamron.co.jp/data/old-lens/olm400f6_9telescopic.htm

Model# YO-8 (1965-1969)

400mm f/8 - 3el/2gr

https://www.tamron.co.jp/data/old-lens/olm400f8.htm

Photo Album

https://photos.app.goo.gl/3NkmFSXQBtheYabW6

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Impressions

Repair History/Defect

The lens elements were all thick with dust and dirt, and there was a balsam separation on the cemented rear group of elements. The shots appear fine, but if you stop down to f/32, you can see a huge dot in the middle of the photo caused by it (Sample 1 in the video). The maximum I ever used was f/16 so it wasn't a problem. Both the focusing and aperture rings were locked tight like welded metal, but they were restored and had a smooth turning afterward.

History

1950 - Tamron was founded by Watanabe and Arai. Its name was derived from Mr. Uhyoue Tamura, a prominent optical designer who laid the technological foundations of the company.

1957 -Creation of T-mount system

1958 - Tamron's first SLR lens, 135mm f/4.5 (Model# 280)

1963 - Tamron created five versions of the 400mm lens under their T-mount system (created 1957). The FO-69 featured here is the third version.

'T-Mount' is an interchangeable mount system created by Tamron in 1957 and still in popular use today. It was succeeded by Tamron's 'Adapt-A-Matic' system from 1969-1973, and later, their popular 'Adaptall' system from 1973 to 2006.

Adaptability

Because it uses the T-mount system, this lens can be adapted to all existing film/digital SLRs and to mirrorless cameras. The addition of a built-in tripod collar also makes it easier to use or easier on the camera body when mounted on the tripod.

Build/Handling

This lens is made of metal but very light, and is no bigger or heavier than your typical plastic 70-300mm zoom lens. It was made before 'auto-diaphragm' came into existence. The aperture control has two sets of rings -- the ring on the top sets the f-stop, the lower ring (clickless) manually opens and closes the diaphragm. The beauty of these old lenses is that the diaphragm blades are metal, they never get stuck no matter how oily it is, and it is common to have anything from 12 to 16 blades (the bokeh balls are perfectly circle no matter what f-stop).

Image Quality

The optical formula is a simple 4-element 2-group count. The elements used in this lens have a single coating with blue sheen. The lens is already sharp wide open, but it could have a soft contrast shooting around bright daylight, which can be a pleasing feature. Because of that, I have a tendency to shoot underexposed shots. Overall, don't expect rich colors and contrast and flare control like modern lenses, but it really does produce pleasing shots.

Conclusion

This was one of my earliest lens demos dating from early 2016. I made improvements and re-uploaded photos and videos. Looking back from 2022, I sure wish to shoot with that lens again and apply the improvements in my shooting skills. What I can say about the lens is that it was very lightweight and no bigger than a typical 70-300mm plastic zoom lens. The image quality was okay but with noticeable loss in contrast, particularly because my copy had issues with the faded coating and balsam separation, but the results were still acceptably good.