Minox HF part 1 – Half the Story

I found a 2nd Minox 35EL at a yard sale, it was in a really bad condition. The top cover was opened without removing the 3 screws hence the screw sockets inside are broken and the top plate was held in place with a tape. The external light seal/coatings were also fading off. Fungus in the internal lens elements, etc.

Luke Skywalker: What a piece of Junk!

Han Solo: She’ll make point 5 past light speed. She may not look like much, but she’s got it where it counts, kid. I’ve made a lot of special modifications myself.

– STAR WARS Episode IV A NEW HOPE

How to turn a Minox 35 into a Minox HF

The following procedures here will involve removing almost all the parts of the camera. Some of the modifications are irreversible. The steps/instructions and images here does not cover all the in-between processes which may include removing small parts that are quite tricky to re-assemble. Please use a 2nd or an experimental Minox 35 camera for this modification. Skills required: Basic repair, attention to detail, patience, fine motor skill, basic soldering, photo & note taking, etc. Tools: Screwdrivers, cutter, soldering kit,

Half frame Film Measurement

Q: Does a single stroke equal a half frame film advance? A: Yes

Measured 18 mm and marked with pencil just below the viewfinder. Film advanced with 18 mm + 2 mm gap between frames. Technically, we are simply moving the edge to the center.

De-couple film advance mechanism from shutter engage mechanism

This step will include removing the lens assembly, ISO selector and the film take up spool.

Remove ISO selector
Move Dial & circuit board out of the way
Remove take up spool
unscrew to remove lens assembly
remove screw on left side as well
This tiny metal rod is the ‘bridge’ between the film advance mechanism and the shutter engage mechanism
to remove the plastic gear

Cutting of the double stroke advance limit/stop on the plastic gear

Removing the Light Meter

Tools: Soldering iron, desoldering pump and paste
using a blade to wedge between the meter body and underside of PCB while melting the solder.

Cooper: Newton’s third law. ‘You’ve got to leave something behind’.  Interstellar

Cutting out a portion of snap plate

By cutting off this front portion specifically the collar, the shutter button metal rod is free to move instead of being locked in the half cycle

Removing the drawbridge and fixing the lens in extended position

swapped the plates so that it covers the gap
reinserting the lens assembly

Eliminate Sound of the Snap Plate (false shutter sound)

In the original design, this plastic gear does 3 things : 1. It primes the snap plate with switch and limits the film advance after a double stroke. It snaps and closes the circuit when shutter button is depressed. 2. It also moves the snap plate with a small arm to advance the film counter. 3. It also acts as a anti reverse gear. We are retaining the gear and snap plate for the film counter. By cutting away the ‘cliff’, the film counter is then advanced quietly and the snapping sound is eliminated.

~0.55 m Close Focus (breaking the 0.9 m limit)

Front element focus dial

The precise distance is yet to be confirmed. The downside of this mod. is that at close focus setting, the light sensors are completely blocked resulting in very slow shutter speeds (motion blur). Solution: Go Manual:- activate 1/30th sec flash switch or 250th sec and adjust the aperture accordingly.

Problem: The camera does not have a proper off switch due to the lens in extended position. Solution: Turn the dial to completely block off the light sensors and set the aperture to f16.

Half Close – Viewfinder & focal plane window

measuring 18 mm

Continued in Part 2.