Update October 2018: The Xenon 28/2 reverse mounted and Schneider Makro-symmar came in at the top of a 4x test against high end microscope objectives and the Canon MP-E 65 here on Closeuphotography.com: https://www.closeuphotography.com/stacked-vs-objectives
This is the 6 element Schneider Xenon 1:2/28 line scan lens in an all metal B00 barrel mount. There is a lot of misleading information online about whether these lenses are mis-named Componons, Cine-Xenons, enlarging lenses, or mini-lab printer lenses, the list goes on an on but I what I do know for sure is that both of my Xenons f/2 lenses were purchased as industrial line scan lenses set-up at a magnification range of 0.5x in normal forward mount complete with adapter and Dalsa line scan camera.
Having owned maybe a dozen different versions of 28mm and 35mm f4 Componons over the years, I always thought these were pretty sharp lenses until I found a Xenon. The Xenons are sharper and much less expensive. Keep a look out for the Xenon 28mm f/2, the 35mm f/2, and the 40mm f/2 Xenon versions and I am told there are other Xenon versions also. If you know more about the Xenons please email me if you would like to share the info.
Update November 2018: This week I managed to find a new-old-stock Xenon 35/2 unopened and still in the factory box on Ebay so Xenon lenses can be hard to find but they are out there. See more below under the Buying a Xenon section.
RATING
What I Like:
Image Quality
Sharpness
Price
All metal body
What I Don’t Like:
5 blade iris aperture shape
Corner sharpness is not as strong as the center
These are difficult to find on the used market
TECHNICAL DETAILS
Schneider Kreuznach 28mm f/2 Xenon in B00 metal barrel
Schneider Optics part number: discontinued
Filter threads: 30.5mm x 0.5
Mount: 25mm x 0.5mm
The Xenons sometimes will come supplied with a 42mm to 25mm step-down adapter. All of my lenses came with a 26mm extension tube with female 25mm x 0.5mm and male 42mm x 1.0mm threads.
Current Retail Price: Discontinued
Typical used price: $30-150 USD
Type: Industrial Line scan
Iris: 5 blades
Magnification range: 1X to 4X and sharpest at f/4 to f/5.6.
Coverage: When used in reverse stacked on a telephoto lens the Xenon can cover an APS-C sensor, and when stopped down slightly the results are excellent. This lens came with a camera with a 32mm wide sensor but the Xenon image circle is not large enough to cover an APS-C sensor at f/2, to f/2.8, but it gets better as you stop down from there. By f/4 or f/4.5 the corners are usable but not perfectly sharp. Compared to an enlarging lens they are okay. Beyond f/4.5 the corner sharpness drops but I find the corners with Xenon better than Componon lenses.
Forward or Reverse Mount: I found that this lens performs best mounted in reverse for 1x and higher magnification.
Buying a Xenon
The Schneider Xenon f/2 lenses can be be a difficult to find sometimes but if you are patient they are out there. Early in 2018 I picked up two Schneider Xenon 35mm f/2 lenses with Dalsa line scan cameras, with extension tube and adapter for just over $100 each and the month before a Xenon 35mm f/2 sold for less than $100. In November 2018 I picked up an unopened new-old-stock Xenon 1:2/35 for just over $100 with free shipping on Ebay. You can see an image of that lens above, and yes, the lens is already spoken for by the way.
MOUNTING the Xenon
Normal mount: For 0.5x magnification I used a no-name E-mount to 42mm x 1.0 adapter and the supplied 26mm extension tube with 25mm female threads and 42mm x 1.0 male threads.
For higher magnification work I would recommend using the lens in reverse mount.
Reverse mount: For 1x magnification to about 2x you just need 3 items, a lens mount adapter, extension tube and reverse adapter. I use a no-name E-mount to 42mm x 1.0 adapter and threads, 42mm x 1.0 extension tubes and 42mm x 1.0 to 30.5mm x 0.5mm reverse adapter (available on Ebay).
For best results at higher magnification, 2x to about 5x, I would recommend using this lens reversed on the front of a telephoto lens.
Stacked Lens Mounting: This is a little more difficult but it still only requires 3 items. I use a Sigma 150 OS macro lens as the main lens, this lens has 77mm front filter threads. I use a 77mm to 52mm step down attached to a 52mm to 42mm step down, with this attached to a 42mm to 30.5mm reverse adapter. This is not the best way but I already have these adapters on hand. In the future I will change this to a thinner adapter stack that is being made for me now. I will update this page once I receive and test the adapter.
Other Schneider Xenon Lenses
On the used market I have seen the Xenon 28mm f/2, the 35mm f/2, and the 40mm f/2 versions of this same type of lens. I own both the 28 and 35 f/2 lenses.
Links for more information on the Xenon
More information on the Xenon 28/2 stacked on a 120mm Makro-symmar:
https://www.closeuphotography.com/makro-symmar-xenon
The Xenon 28/2 + Schneider Makro-symmar 4x test:
https://www.closeuphotography.com/stacked-vs-objectives
Xenon f/2 lens discussion on Photomacrography.net:
This is an older discussion but there is still interesting with lots of info.
http://www.photomacrography.net/forum/viewtopic.php?t=7354&