A few weeks ago I found a good looking unit complete with a camera for a good price, $250, and most importantly the seller accepts returns.
This is the Kubotek Rayfact 80mm f/3.5
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This is what I know about the lens so far.
Kubotek Rayfact 80mm f/3.5
Part Number: KLN-80-F3.5-4
Type: Industrial Large format 12K Line-scan Lens
Magnification range: 1/4x to 1x
Kubotek camera sensor pixel pitch: 4?m
Focal length: 80mm
Aperture range: f/3.5 - f/11
Sharpest aperture: f/4
Lens mount: This lens has M41 P=0.5 threaded mount
Filter thread: M61mm, unknown pitch.
First the bad news:
The Kubotek camera that this lens was made for has a 36mm register or FFD. First time I tried the lens on my D850 I had to use way too much extension and the F-mount register of 46mm didn't help. It was too far past 1x and the results were not good.
My lens had a fungus issue.
The lens tube interior is not flocked, the shiny black interior flares (like most industrial extension tubes I own).
The good news:
On my Sony A6300 I was able to set the lens up with a 36mm register and this gave me a 1/4x to 1x magnification range.
This is what the lens looks like at 1.4x and 1x magnification settings.
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Its seriously sharp at 1x, even wide open at f3.5 although f/4 is slightly sharper.
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This is line scan lens so the image quality is consistent from edge to edge.
Placing a sheet of rolled up flocking material into the rear of the lens stops the flare.
The fungus issue
This was resolved by the the seller crediting my payment once I asked Ebay to step in. Once I received the credit I pulled the lens apart.
There are two sealed lens cells inside that mount to the cam sleeve. best of all, only one surface of the front cell had any fungus and there was no coating damage.
Fungus before cleaning.
Tripod mount
This lens does not have a mount so you will have to use the camera body to attach a quick release plate but I did find that this old Tamron ring works perfectly. There is one on Ebay right now for $18 BTW.
Kubotek Rayfact lens with Tamron tripod ring.
Image quality at 1x
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Camera: Sony A6300
Sensor size: 23.5 × 15.6 mm. APS-C. 28.21 mm diagonal. 3.92 micron sensor pitch
Flash: Godox TT350s wireless flash x 2 with one Godox X1s 2.4G wireless flash transmitter
Vertical stand: Nikon MM-11 with a Nikon focus block
These are all single images.
The sharpness is impressive. The lens has almost no detectable drop off across the frame on APS-C and CAs are very well controlled even in the corners.
I will be updating this project with more images and comparisons once I am back from a 1 week trip next week.
Also I will update this post once I get a custom made adapter tested.
You can see more images and more info on my website:
https://www.closeuphotography.com/nikon ... 80mm-lens/
Questions and comments welcome.
