Masuyama = Ohi Optical Manufacturing
Let me write up the summary of the legendary company history and background.
[Masuyama] is originally the name of the founder. A current owner is still Mr.Masuyama, so the founder’s philosophy continues to be alive and all are still fully produced in Japan. Deeply concentrating on Japanese production. That’s the excellent company policy.
Meanwhile, Ohi Optical Manufacturing Co., Ltd.(OOM), which is the name of company. As Nikon serious fan might be aware, [Ohi] is the name of the location inside Tokyo, which is well known as Nikon’s home ground. Let’s say like Rochester of Kodak? and Jena of Carl Zeiss?? maybe something like that.
So more than half century ago, OOM started the business besides “Nippon Kogaku Kogyo Co., Ltd (an original name of Nikon) to provide eyepieces to Nikon. It seems to have been very close relationship each other.
A following is one example. This was the award from Nikon for inventing eyepieces to the founder – Ichiharu Masuyama in 1946.
Since then, they have been making high quality optical products including various eyepieces. Current Japanese Abbe Ortho eyepieces are known as OOM production too.
Also they, as OEM, made so many number of eyepieces under various brands so far.
Masuyama philosophy still exists in the products. This is to summarize current super-wide Masuyama brand eyepieces.
Current Lineup + 20mm just released a couple of days ago
Beautiful piece of optical equipment!!