Browsing Ebay I came across this unnamed lens being sold by a Silicon valley surplus dealer. The seller was not able to provide any info other than that is was new-old-stock and the $29 asking price but a couple of things made the lens very interesting; the lack of mounting threads, the industrial unmarked heavy barrel, and the white alignment marking on the edge of the lens. My experience tells me these characteristics say it’s a scanner lens. So for $29 it was definitely worth a chance. There are still some amazing finds on Ebay but the question is, would this lens turn out to a useful find, or an expensive paper weight?
The lens measures exactly 50mm in diameter and is 75mm long and has a nice heft but no external threads. This is the 95mm Scanner Lens X next to the Minolta 5400 and PrimeFilm 3650 scanner lenses for scale.
Lens Specifications
Objective type: scanner lens
Aperture: f/3.4 no iris
Focal length: 95mm
Magnification Range: 1.5x - 2x
Length: 75mm
Barrel diameter: 50mm OD
Working Distance: Very good.
Chromatic Correction: APO corrected
Resolution: Very good.
Designed lens coverage: APS-C
Mounting Threads: None. The RafCamera 51mm ID to 52mm x 0.75 adapter made mounting possible, this adapter is available online.
Country of origin: unknown
To find the focal length I used this simple formula:
FL = Added Extension / ( New Magnification - Old Magnification )
FL = +43 / (2.05x - 1.6x )
FL = 95mm
To measure the speed of the lens used a macro lens and with focus peaking I made an image of the front lens pupil, than another of the rear pupil being careful not to change focus, finally I made the last image of a ruler for reference being careful not to change focus/extension between frames.
F-number = FL / Aperture
F-number = 95mm / 27.4mm
F = 3.46
95mm Scanner Lens X vs. Canon MP-E 65mm f/2.8 1- 5 x macro Lens Comparison
For this comparison at 1.6x the Canon MP-E 65 was tested from f/2.8 to f/5.6 and f/4.5 was the best aperture. F/2.8 - f/4 were not any sharper but these apertures did show more chromatic aberration.
At 1.6x magnification the image quality was almost identical from center to corner so I decided to compare only the center in extreme corner since the other areas look almost exactly the same.
Both lenses look excellent in the center but the Scanner lens X has slightly better resolution, look at the tiny hash marks and the S311001A marking. The Canon MPE also shows some CAs, where the SLX is CA free. Look at the left side of the small blue square to the right of the S311001A.
There is almost zero drop off in image quality in the extreme corner area, both lenses are excellent here. The SLX may have a slight advantage in sharpness here but they are very close.
Test Conclusion
Both lenses are very good to excellent at 1.6x magnification. Overall the 95mm f3.4 Scanner Lens X is slightly sharper and has a little more resolution with better CA control than the Canon MP-E 65 at 1.6x.
If you can live with a fixed f/3.4 aperture, the 95mm SLX is highly recommended.
2500 Pixel Image Samples
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Another 2500 pixel sample, this time at 1.8x magnification.
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