Have you ever made a big enlargement where the enlarger head was so far above the base board it was impossible or too awkward to reach the enlarger focusing knob while looking through the grain focuser? I have and decided to find a way to make it easier.
Can’t reach focus knob while looking through grain focuser
There are a few solutions to this problem. Omega made a flexible focusing shaft (P/N 464-055) which can still be found on line. Saunders/LPL made a generic flexible focus extension that is apparently no longer available. KHB Photografix sells a version deigned for use with the Omega Micromega Fine Focus Control and another version that works with the main focus control.
Being a penny pincher, I wondered if there might be a cheaper way that didn’t challenge my lazy lifestyle too much. What I came up with was a simple lever that extends down from the focusing shaft. The procedure is to set up the enlarger as I normally would to make a large (or heavily cropped) print, focus as I normally do, but then simply replace the focusing knob for the long lever to do the critical focusing with the grain focuser.
The materials to build the lever are below. Dimensions should be adjusted to meet your own requirements.
- Pine wood strip 3/16″ thick x 1-1/4″ wide x 27″ long.
- Aluminum rod 3/8″ in diameter x 7″ long.
- #10-24 machine screw and washer.
- 3/8″ shaft coupler (available on Amazon)
The wood strip needs to be light, but rigid. The length of the aluminum rod should be long enough to keep the lever out of the image area. The shaft is attached to the end of the wood by drilling the appropriate hole in the end of the shaft and tapping the hole to accommodate the machine screw. I had a #10-24 tap handy, so I drilled a 5/32″ hole and threaded the hole to accommodate the length of the screw.
The ruler is just for scale. Note the small piece of sandpaper at the hole on the left end of the wood.
Painted black and assembled.
Small piece of sandpaper glued to wood ensures the rod won’t rotate.
Allen wrench sizes are 5/64″ for the knob and 3/32″ for the coupling.
I couldn’t reach the focusing knob, but can easily reach the lever for critical focus.
The lever extends down where I can easily reach it. “Easily” is a relative term. Since I will be on my knees to look through the grain focuser, it is not as comfortable as when I’m standing up. I don’t think the flexible shaft focuser would be much better.
The secret is to hang the lever on the focusing shaft so it is vertical before tightening the set screw. The lever is then moved to effect a small rotation of the focusing knob, making it easy to fine tune the focusing. If you did a reasonable job eye-balling the focus during setup, the fine adjustment is very small.The light weight of the lever is not enough to turn the focusing knob by its own weight, so once you adjust it, it stays put. I also found it to be a simple matter to remove the coupling from the shaft without corrupting the focus.
The lever is light, so it will not rotate the focusing shift by its own weight.
I did not tighten the friction tension on the focusing shaft for this project, nor do I consider the focus particularly stiff on my two D5s, but even if you have your focus set to be more loose, the lever will likely never be at much of an angle from its initial vertical position, so the torque will be very tiny.