Here’s some additional history on DO Industries – apparently they go back even further than I thought. The original company was founded by Ernst Gundlach, who used to work for Bausch and Lomb. After parting ways with the B and L in 1878 (unwillingly, it seems), he partnered with Lewis Sexton and opened a Optical goods business.
For a while, Sexton ran the business while Gundlach left to work as an Optician in Hartford Connecticut. Sexton was joined by JC Reich and J. Zellweger. On Sexton’s death in 1884, Gundlach returned to the company he had founded, and reorganized it. After about 11 years, Ernst Gundlach left the company again, and formed a rival company called the Gundlach Photo-Optical Company, which was finally acquired by Wollensak in 1905.
The original Gundlach Optical Company continued to operate in Rochester, first acquiring Milburn Korona cameras and then in 1902 they acquired the Manhattan Optical Company and renamed themselves the Gundlach-Manhattan Optical Company. In 1926, they were renamed as the Gundlach Manufacturing company. In 1928, they were taken over by a John Seebold, and were renamed “Seebold Invisible Camera Company” (no idea what they were making).
After taking a beating during the Great Depression, they moved to Fairport in 1935. They survived until 1954, when they were acquired by Burke and James of Chicago and reorganized as the Dynamic Optics Inc, with Mr. David Goldstein as president. Dynamic Optics ceased operations in 1972 and were reorganized as D.O Industries. The rest of the company’s history can be found on the Navitar website.
My original post on the DO Industries 135mm lens discussed its use as a Bellows Lens on the Sony Alpha 700
A History of the Rochester, NY Camera and Lens Companies
Gundlach is also referenced in the famous Lens Collectors Vade Mecum by Wilkinson and Glanfield.