Finite Optiphot trinocular heads with infinity prism space

back

Finite Optiphot trinocular heads with infinity prism space

"F" trinocular head objective rays focus directly;
"T" and "UW" heads convert rays to near infinity around prisms:

Nikon's CF PL chimney has an M50x0.75 external thread and positive lens.

scars from failed attempts to unscrew M40x0.75 thread

Removing that chimney (or at least pos. lens) passes infinity rays...
Alternatively, removing that negative lens would focus infinity objectives,
but with a bit under a 0.5x magnification.
Instead, parting the chimney immediately left of its M40 thread,
then screwing an M42-M40 step-down ring on that:

...enables attaching an M42 to mirrorless camera flange adapter

200mm zoom telephoto

A camera with (250mm) telephoto lens focused at infinity,
as discussed on photomacrography.net:

Canon 90D+250mm

... captured these images:

stainless millimeter rule

calibration slide
same target as below

... but strongly vignetted images are magnified about 3X relative to oculars:

ocular scale (image by iPhone)

This scale issue is addressed by T / UW "direct" projection
and arguably better using a Zeiss Triotar.

maintained by blekenbleu