Right after I promised, for the 10th time, to stay off Ebay, I came across another deal that looked too good to pass up. A line-scan machine with servo motor driven X-axis stage, camera, tubes, adapters and a lens. Question is, what lens was it built around?
Since the lens was covered in electrical tape, it was impossible to see any details, but I did recognize the Schneider front lens cap! Feeling lucky, I took a chance and paid the $100 asking price. I couldn't resist.
Underneath all the tape and residue, was a Makro-Symmar HM 120mm. The lens included a really well-made 2 inch long adapter that took the odd-ball 32.5mm threads to a standard 42mm x 1mm. The adapter attached to a 5 inch long thick-walled 42mm x 1 extension tube, both with extra-long threaded sections.
Schneider recommends the 120mm Makro-Symmar for 12K machine vision applications for sensors with a 5µm pixel pitch and a line-scan sensor size up to 12,000 pixels wide. That is interesting, since that is a pretty good match for the D810 with 4.88 µm pixel sensor and the D850 with 4.35 µm sensor. Its also interesting that the 80mm Makro-Symmar is not recommended for 12K sensors.
This lens is available in a few mounts, this metal lens body is known as B-0 iris mount.
If you are not familiar with the Makro-Symmar lens, it's a true macro lens, optimized for 1:1 reproduction, sharp and chromatic aberration free at 1X, thanks to the ULD (Ultra Low Dispersion) glass in an 8 elements, 4 group design.
When I received the lens had no idea what to expect of the 120 Makro-Symmar performance. I do own an 80mm Makro-Symmar but the performance was not that good.
A 12K line-scan spec lens, like the 120 M-S lens, should be excellent on a DSLR like a D810 or D850. I was right in the middle of a studio 1X sharpness test when I got the lens, so of course, I included it, and I am glad I did.
Check out the test results below. Schneider Makro-Symmar HM 120mm on the left, Nikon AF-S VR Micro-NIKKOR 105mm f/2.8G IF-ED on the right, both at 1x, f/5.6 and 100% magnification, all lens correction and noise reduction zeroed out in photoshop ACR.
At the center the Makro-Symmar has a slight sharpness advantage, at least in the lettering, over the Micro-Nikkor, but it is close. Be sure to click on an image below to launch a new window with a full size image.
The corner crops show a huge difference in image quality. The Schneider lens is surprisingly clean and sharp right to the very edge of the frame. The Nikon, not so much.
This is an interesting comparison, but it's not really a fair since the Makro-Symmar is a more expensive lens, and it is optimized for 1:1. The Nikon 105 VR is about $800-900, or 40% less than what the Schneider costs, has AF, VR, and can give you sharp results from infinity to 1X. The Nikon 105 VR has one ED element, the Schneider doesn't say how much ULD glass is in this lens, but I can guarantee you it's more than one element. Anyway, the results are interesting!
Wafer with 1X test area outlined with blue tape.
1X test area with the crop areas highlighted.
More Info
If you are interested in learning more details about the 120 Makro-Symmar lens follow this link to another page on this site:
https://www.closeuphotography.com/schneider-makro-symmar-120mm/
Also to see the test results of all 16 lenses in 1X sharpness test, follow this link:
https://www.closeuphotography.com/sharpness-test-1x/