Any info on the National Optical Company & Stewartry

[pgk]

I have a Stewartry Trinol lens which has a lens head made by the National Optical Company of Leicester (a 'daughter' (subsidiary?) of Taylor Hobson) and the focus mount (Leica screw, RF coupled) is marked 'Made in Scotland'. Despite searching I cannot find any really specific information about either brand. No addresses even, in fact very little at all. Were they both simply a wartime designation and really parts of the strategically disseminated Taylor Hobson business, or did they actually exist as distinct entities? Any information would be useful. I suspect that the 105mm f/3.5 Trinol may not have been a straightforward 35mm design - it may have been a larger format lens - mine mechanically vignettes as the corners are clearly blocked by the tube which suggests to me that the physical design was added to an existing lens rather that being a cohesive one. Thanks.

[Dan Fromm]

https://www.photrio.com/forum/threads/details-of-trinol-lens.143685/

[pgk]

Thanks Dan, that information is useful but I cannot find anything further. Neither Stewartry's not NOC's addresses which is very odd given that at least NOC should have been a Limited Company and thus traceable.

[Dan Fromm]

From the VM:

Stewartry, Glasgow, Scotland.
Also as G.B.Montgomery Manufacturing Co.
Stewartry were not lens makers but rather were a small company making focusing mounts for Trinol (NOC)
and Definex (Ross) lenses about 1947, as well as a few accessories. See J. Anderson, Photografica, 1996.,
See also MCM June 1947, on the PPI enlarger, July 1947, and for a favourable review of the Trinol (TTH/NOC)
and Definex (Ross) lenses.) Trinol is illustrated in B.J.A. 1948, p459advert. for Leica.
You might find more in late '48s BJP annuals, and you're much better situated to find them than I am.

[pgk]

Thanks Dan, I now have an address in Glasgow - as anticipated they were a small precision engineering firm by the look of things, and must have shifted into photographic production during WWII and stayed there until the changes in the British optical industry may have resulted in supply problems with lenses. As Rank Precision Industries bought up optical companies there must have been 'rationalisation' and supplying small quantities of lenses to a minor customer may not have been worthwhile. Oddly enough a quick search reveals one lathe made by Montgomery!