Up until few months ago, I have never heard of a name Dallmeyer. One tiny c-mount lens, called the Dallmeyer Speed Anastigmat 1 inch (25mm) f1.5 came with a bunch of other miscellaneous stuff I bought. Didn't pay any attention to it as I could not use it on my DSLR. After I acquired the Panasonic DMC-G1, I started to look at lens options, including the c-mount lenses. To my surprise, I already had a few c-mount lenses. One of which is the Dallmeyer 1 inch cine lens.
Dallmeyer was an English optical manufacturer that made optical instruments, lenses, cameras, etc, from 1860 until the company disolved in 1993. Dallmeyer produced lenses with exceptional built and optical quality. My 1 inch f1.5 lens is at least 80 years old, and from the look of it, you would swear it looks like it was made 10 to 15 years ago. The only hickup is the rather tight focusing ring, due to grease dried up. Everything else works perfectly.
Optical Quality -- If you are the type that demands a lens to be sharp corner to corner, this is not your lens. The lens produces images with swirling backgrounds. The edges are not sharp at all, and stopping down does not seem to help either. The sharpness at the center, though, can put many of today's expensive lenses to shame, even wide open. Remember, we are talking about a lens that's around 80 years old.
Although there is no marking on the lens that says this is a macro lens, it can focus as close as a 18 inches. Surprising, really.
The quirky part? If you want your subject to be sharp, you have no choice but to put it smack in the center. Remember, the edges are not sharp at all. The lens vignettes on the G1 with its original hood. Not really the fault of the lens.
To be sure, this is not a lens you use daily. You will get rather tire of the swirling backgrounds. In deed, I get headaches looking at the pictures for an extended period. But, if you are looking for a lens with unique signatures, great built quality, and excellent sharpness (in the center), do get one if it can be had at a reasonable price.