H A L F - F R A M E

There's been so little documented about this camera, my goal for this project is to provide as much info as possible including a little history, documenting my modifications and of course - the images I manage to wrangle out of it.

The Pentax MF is a specialty half-frame 35mm SLR that was produced in the late-70's for medical and industrial applications. Built off the more common ME chassis, each one was hand-tailored by a factory technician to suit the needs of imaging through endoscopes and microscopes. It's unknown how many units were produced but with clear evidence of hand modification under the hood, these were not produced en mass. Pentax also made a full-frame version of this camera called the MF-1 as well as a similarly modified full-frame MX .

While the MF does use Pentax's popular K-Mount lens system, the traditional ground glass focus screen was swapped for a transparent magnified screen that complimented the native lens/adapter (ie. PA-M55). Additionally, the typical center-weighted light meter was replaced with a spot meter. Alterations were also made to both the shutter speed timing and the lens mount assembly to allow for function with the endoscope attachment.

These factory modifications made the MF extremely functional for the needs of a 1970's lab tech. Unfortunately, most of these modifications made its use as a standard(or even semi-troublesome) artistic camera nearly impossible. This unusability factor has since made it more of a showpiece among collectors.

But the allure of a user-friendly half-frame K-mount SLR has tempted a brave few...

In an effort to be able to achieve precise focus through the eyepiece, Jeff Greenstein took the leap and successfully replaced the focus screen on his MF. He followed it up with a fantastic article about his journey on The Casual Photophile and has also mentioned it a few times on his podcast I Dream of Cameras.

I discovered Jeff's story while anxiously awaiting my own MF's lengthy and somewhat worrisome delivery and knew there was hope for at least a small modification to increase usability.

What I didn't know is that hope would snowball into something completely unique and wildly functional.

Hop over to the mod page to do the deep dive.