Miles.
Beamsplitter
I recently acquired this early NKT 5cm f1.4 lens and noticed an odd engraving on the barrel. Any ideas what it means? Dealer engraving? Old corporation or government logo?
Mr. Rotoloni has not seen it before.
Mr. Rotoloni has not seen it before.
farlymac
PF McFarland
Something having to do with GN (flash Guide Number) calculation?
PF
PF
It looks more like a "Cattle Brand"- maybe a company bought the lens, and that is a "branding".
It is cool.
It is cool.
Miles.
Beamsplitter
Haruo Sato, who runs Nikon's "The Thousand and One Nights" replied in a different forum:
"This is thought to be a mark meaning "tool (工具＝kougu)" that was used by Nippon Kogaku."
He said he couldn't be certain, but that is the prevailing thought amongst people who know much more about Nikon than I do.
"This is thought to be a mark meaning "tool (工具＝kougu)" that was used by Nippon Kogaku."
He said he couldn't be certain, but that is the prevailing thought amongst people who know much more about Nikon than I do.
SO- this lens was a benchmark lens USED by Nikon!
No need for certainty- sounds good to me!
No need for certainty- sounds good to me!
Coming from Sato-san, it seems likely. 
I did some searches for a similar icon/logo/symbol (including AI) but didn't come up with anything.
I did some searches for a similar icon/logo/symbol (including AI) but didn't come up with anything.
Miles.
Beamsplitter
I agree, but I wanted to respect his restraint.Coming from Sato-san, it seems likely.
I've seen his posts on fb, always measured.
farlymac
PF McFarland
That actually was my first thought, but it looked so much like a lightning bolt I went with the GN hypothesis, though seeing as it was not something that showed up in any production runs that it might have been an experimental unit.
PF
Miles.
Beamsplitter
I really don’t know what the odds are but I just found another on the big auction site — this one is an f2, and seems to be in better condition, optically, than the one I purchased.
Nikon NIKKOR-H.C 5cm F2 Standard Prime Lens L39 Leica Nippon Kogaku Japan Ex5 | eBay
[Excellent5]Nikon NIKKOR-H. Optical system. There are tiny dusts inside,which never affect photos.
www.ebay.com
Nice catch, I wonder if the seller has any info. Likely not, but maybe worth an ask.
Miles.
Beamsplitter
Knowing my lens is c. 1952, and this example is likely c. 1958, suggests it might’ve been a pretty established practice.
xayraa33
rangefinder user and fancier
I wonder if it is the logo of a large chain of Japanese photographic equipment stores or the Japanese version of a Japanese PX store for its Self Defence Force ?