First Scanner Build - Help Choosing A Lens

Machine Design
1

Hi there,

So hoping I can get some advice on choosing a suitable lens for my first scanner build project.

I already have the following :

  • Camera - Blackmagic 4k. Micro Four Thirds size sensor measuring (18.96mm x 10mm). Native resolution of (4096 x 2160) (DCI 4K) and provides 13 stops of dynamic range. Can used either as frame by frame or record continuous video.
  • Projector - Elmo K-100SM dual format projector. All electronics and lens removed. Belts replaced, gears cleaned and regreased.
  • Motion - NEMA 17 stepper motor, Bigtreetech PICO controller, under PC control
  • LED - SunlikeKorea COB LED SAW0661A CRI 97 7W. MEAN WELL LDH LED Driver. Lee 216 Full White Diffusion. Heatsink, fan etc
  • Camera trigger - Optocoupler
  • Post Processing - Davinci Resolve Studio

Without the lens fitted in the projector, there is approx 80mm from the gate to the front of the projector where a lens with a diameter of 75mm could fit. If the lens was to be closer than that then the diameter would have to be less than 40mm.

I have looked at the following lenses but to be honest I am going round in circles and am not an optics expert so dont really know what lens will work best for this application and whether some are overkill as they seem to be very expensive options:

  1. Mitakon 85mm f/2.8 1-5x - 100mm+ working distance. But like hens teath to try to find one with either a micro four thirds or cannon ef mount. Estimated used price £350-400
  2. Rodenstock Apo-Rodagon-D 2x 75mm - Excellent quality, but quite a considerable kit of parts needed to make it work. Estimated used price for bellows, tubes, attachments and lens £650 – £750
  3. ultraVU-EL Zoom System - excellent quality, but soooo expensive by the time all the necessary accessories are included £950–£1,100
  4. Olympus OM Zuiko 80mm f/4 Auto-Macro - older high quality lens designed for medical/scientific scanning, needs bellows/tubes, used £150 – £250
  5. OM-System 90mm f/3.5 Macro/OM MC-20 (2x Teleconverter) - simple system, great quality but very expensive approx £1,500

I am thinking about going with the Olympus (#4) as that seems by far the best bang for your buck. After that it would be the rodenstock (assuming i could find one) as that seems to give the best quality (APO) but is a significant step up in price.

If anyone can help with advice about these lenses, alternatives, or even potentially best sources to purchase these.