focal plane microscope

That’s a Zeiss Planar 85mm T1.4 Super Speed (focus and iris scales removed) mounted on my prototype Focal Plane MicroSCOPE that I built when I had my workshop in Maine.

Note how the Planar 1.4/85 perfectly resolves the core of the Moeller-Wedel Siemens star reticle. You’re seeing that at 65x magnification. Pretty good for a 1974 optical design! No wonder these vintage lenses are legendary.

Unlike the more common Focal Plane MicroMETER which reflects the image back to the collimator, this system captures the actual image formed by the lens. That image on the monitor is NOT from the collimator eyepiece, it is the aerial image formed by the lens, magnified 65x in this case.

I needed the Focal Plane MicroSCOPE properly adjust the rear group centering on the Zeiss Distagon 1.2/18 and 1.2/25 that were part of this set. The adjustment screws are UNDER the lens mount. If you try do do this on a lens projector you have to remove the mount for EACH adjustment. It could take you all day.

The Zeiss Distagon’s optical centering was adjusted using a pinhole reticle on my collimator and observed the resulting image at 165x on the Focal Plane MicroSCOPE. It was then a simple matter to perfectly adjust centering.

You may have heard about inverted vertical collimators (such as Angenieux) that are so highly coveted by lens techs. They work on the same principle but with the microscope above an inverted lens.

The Zeiss K8 MTF Tester uses the same optical principle with the collimator mounted above the lens (non-inverted vertical collimator).

I’m working on a new design Focal Plane MicroSCOPE that will be more compact than the one in the photo above and can be mounted on a standard ARRI compatible 19mm bridgeplate.

I’ve had many requests for this from my lens rehousing clients. The main use would be for precisely calibrating focus scales. It can also be used for adjusting lens centering.

An image of the new design can be seen above. It is still in design development. If you are interested in such an instrument please get in touch via email. Pre-orders will begin once the design is locked.

-Jorge Diaz-Amador ©2024