From the markings on the barrels, these appear to be lenses made by JML Optical. It shows how painstaking it is to make high quality lenses. I thought it was interesting to see the strange mix of high-tech (vacuum chambers and electron beams) and low-tech (wooden sticks and plastic cups) manufacturing methods used in the production of one lens.
How camera lenses are made
By
John Watson
this one is much more interesting: http://www.canon.com/camera-museum/tech/l_plant/f_index.html (:
Thank you for sharing, John. I have a background in manufacturing engineering, so this stuff always interests me. For the operation they had, the thing that really seemed inefficient was the markings on the barrel. What a slow process.
It makes you appreciate the cost of Nikon and Canon’s nifty fifty.