Nerd alert: LensRentals.com gets custom-made lens calibration rig, geeks out hard in blog post
posted Monday, March 31, 2014 at 11:22 AM EDT
Get your MTF charts ready: Roger Cicala and the team at LensRentals.com just got a new lens calibration tool, and documented the setup for all to see.
Cicala writes that for the past year and half, he’s been on "a Holy Quest, trying to find better ways to optically analyze and adjust bad lenses.” Factory service just didn’t seem to do the trick, rendering some lenses “unrentable” without a great deal of effort. The result of the quest is a machine custom-built for LensRentals.com by optical engineering firm Optikos.
In a nutshell, the rig shines 5-micron lasers through a lens from various angles to gauge how it handles fine points of light, suggesting how certain elements should be adjusted to attain a sharper result. Sure, you can calibrate a de-centered lens without this rig, but Cicala writes that it typically involved 20 to 40 rounds of trial-and-error, guessing which adjustments to which elements might boost the MTF 50 and shooting charts to find out if it worked. With this machine, it’s much easier to find the source of the softness, so to speak.
Of course, being one of the internet’s Great Explainers of the technical aspects of cameras, lenses, and optics in general, Cicala does a much better job describing the science and engineering behind the rig. There are some examples that'll make you "queasy," as Cicala puts it, like a close-up look at a Canon 50mm f/1.4.
Check out the post at LensRentals.com for more, and help them settle on a name for the thing while you're there. We are positively stoked to see what else he learns with this mighty new machine in his possession.