Lens on 35mm Helmet Cam

[RonVol]

These photos of Jackie Stewart & Graham Hill using a Gordon Enterprises 35mm Helmet Cam have been 'doing the rounds' of the forums for quite some time.
I've always been curious as to what lens is mounted to that Nikon F.
At first glance it appears to be a Nikkor-O 2.1cm f/4, but looking at it closer..............perhaps not.

Can anyone else hazard a guess as to any other wide-angle lenses (that are non-Nikkor) that could be attached directly to an F-mount?

[Bjørn Rørslett]

The front element is too large for the 2.1 cm f/4 Nikkor-O.

Might be a modified Takumar (Pentax) 18 mm fisheye. A Spiratone 17 mm could be an alternative as well.

[Erik Lund]

I believe Bjørn is right about the Pentax, in the first image it's fitted with a filter.

Would be quite easy to modify for Nikon F mount,,,

Thanks for posting these vintage images! Great

[RonVol]

That's great guys, thanks for the lead.
Looking at images of the 18mm, it certainly looks very similar to the one shown on the helmet cam.

[Akira]

Intriguing images, Ron!  A fisheye fitted with a filter thread should give a smaller image circle.  The F body is also modified to a half frame camera like the elusive S3M perhaps?

[MFloyd]

Great pictures ! Or the ancestors of the GoPro...

[RonVol]

I have quite a few more images showing early Nikons being adapted for this type of photography.
I'll create a new thread over in the Camera Talk section.

[RonVol]

A fisheye fitted with a filter thread should give a smaller image circle.  The F body is also modified to a half frame camera like the elusive S3M perhaps?

A good point Akira.
That F may well be modified to be a half-frame model....................it'd be very rare if it were.

[Erik Lund]

Intriguing images, Ron!  A fisheye fitted with a filter thread should give a smaller image circle.  The F body is also modified to a half frame camera like the elusive S3M perhaps?

There would be vignetting in the corners of a 24x36 frame yes but it should be ok for a letterbox format I guess Anyway - it might be another lens,,, It definitely appears to have front threads or a lens hood, the Takumar is without threads,,,

Edit: Looks like it could be a reverse-mounted filter in the first image,,,

http://whitemetal.com/pentax/f-e-t_18_11/index.htm
http://www.pentaxforums.com/lensreviews/Fish-Eye-Takumar-18mm-F11.html

[Bjørn Rørslett]

The 18 Takumar was not a circular fisheye.

[Erik Lund]

Yes Full Frame Fisheye and it seems that it barely covered even 24x36mm,,,

[Akira]

Edit: Looks like it could be a reverse-mounted filter in the first image,,,

A reverse-mounted filter in this proximity would hit the front element of the fisheye.  Judging from the rugged and worn edge of the hood-looking part, it could be just a bumper to protect the front element.

[Erik Lund]

The front element is almost flat on the Takumar, most likely also why it doesn't cover the frame so well.

[Akira]

Yeah, probably you are right.  This "fisheye" Takumar only covers 148 degree...