Machine vision lens comparison : 8 mm, 8.5 mm and 9 mm lenses from Schneider Cinegon, Navitar, "TV LENS", Edmund Optics, and Fujinon

For at least a decade I've been using Fujinon lenses on my machine vision projects.  I've never had a complaint.  They're solid metal and glass lenses with locking screws.  The image quality has never been in doubt.

However, I've hadn't actually tested the image quality against the competition.  So, now I have tested 5 lenses with a couple of my lab cameras.  The goal of the test was to see if the Fujinon lens had an obvious problem.  I bought a star target array from eBay seller  VitaMall.  Then set up a test rig to image the target.

The lenses tested were fixed focal length 8 mm, 8.5 mm and 9 mm.
Lenses are:

Schneider Kreuznach  Cinegon 8 mm f/1.4 Color Corrected Schneider Compact VIS-NIR Lens ($1600)

Navitar NMV-8   8 mm f/1.4 ($113)
eBay store

"Japan TV LENS"  8 mm f/1.3 (?$120)

Edmund Optics 8.5 mm f/1.3 58000 C Series ($250)

Fujinon HF9HA-1B  9 mm f/1.4 ($130)

They cost anywhere from $100 to $1600.  And that bring up another question, is a $1600 Schneider lens really that good?

Here's the star target at a working distance of 350mm and an f-stop of f/4.0.

Schneider 8mm @ f/4.0

Navitar 8mm @ f/4.0

"Japan TV LENS" 8mm @ f/4.0

Edmund Optics 8.5mm @ f/4.0

Fujinon HF9HA-1B  9mm @ f/4.0

The most noticeable characteristic is distortion.  Yes, the Schneider lens is clearly the least distorted.  But surprisingly, the Fujinon and the "TV LENS" are a close second.

In a future post I'll compare the contrast in the center and the edges.