My favorite source of aluminum (and other metals):
http://www.onlinemetals.com
Not connected with the company, just a happy customer. Fast and efficient
service.
Zack
On Thu, Apr 4, 2019 at 7:33 AM Myron Gochnauer <goch@xxxxxx> wrote:
What I don't know is about the lens boards, and really haven't found a<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon>
picture of one. Some are quite simple, but others can be quite complex.
If its just cutting the right size piece of metal and putting the right
size hole in the center, that I can handle. If there are threads involved,
it has light traps and other things as a part of the lens board, that could
get much tougher. Any help would be appreciated.
My first 4x5 was a Linhof III. I was a student at the time, so I lacked
both money and workshop equipment. I made lens boards from a piece of
aluminum that was about the same thickness as one of the official boards. I
don’t know what thicknesses sheet aluminum comes in, but it was “off the
shelf” and on the fat side of 1/16”. I got the sheet aluminum at a scrape
metal dealer. I just put an official lens board next to pieces of aluminum
and felt them between thumb and forefingers until they were about the same.
I traced an official board, including the centre hole, on the “new"
aluminum. I then rough cut it with a hacksaw and smoothed it to exact shape
with a file.
The lens boards for the Linhoff III are 100m tall and 93+mm wide, with a
tiny notch centred on the base, and a wider notch or angled groove
somewhere around the hole to accommodate the screw that is usually on the
back of the shutter to keep it from turning in the lens board. I usually
centre punched the hole by eye, and roughed it out with a hole saw on an
electric drill. This was a *really cheap* hole saw. I chose a size smaller
than the shutter required, and then slowly enlarged it with a half-round
file. Since I had traced the hole on the aluminum, I could slowly enlarge
the hole in a way that remained centred on the board. (I don’t know others’
filing technique, but I found that firmly running the half-round file
around the hole, rather than back and forth through the hole, gave the
smoothest results and allowed me to get it well-centred.) Finally I
smoothed everything with fine sandpaper, and painted it flat black.
The official lens boards have a slight indentation where the camera has a
raised fuzzy edge. I never had a problem with perfectly flat-backed lens
boards. At a later stage, when I acquired a Linhof IV and then Master, I
started contact cementing a layer of coarse-threaded black fabric to the
back of the lens boards. (Cement the lens board to a piece of the cloth,
and when it is dry, cut it out with a sharp knife.) The later official
Linhof boards have fancy raised light traps, but cloth-backed flat boards
work just fine for me. (It wouldn’t be hard to make wooden “rings” to epoxy
on the lens board backs if you really wanted baffles.)
If you don’t have a lens board to copy, you can make a mockup with 4-ply
mounting board. Get the 100mmX93mm size, notch the bottom, but it on the
camera and from the inside of the camera draw around the hole with a
pencil. That should be close enough to make the real thing.
In short, Linhof lens board as easy to make.
The Linhof III has two drawbacks:
1) It used tiny notches permanently filed into the track rather than
flip-up, adjustable “infinity” stops. (This is annoying only if you want to
use the rangefinder with focal lengths that did not come with the original
lens set.)
2) There is no forward tilt with the front standard. The easiest solution
for tilting the lens down is to mount the camera on its side and use front
“swing”. That requires a strong tripod head or an L-bracket for the camera.
On the positive side, the latest Model III’s (from 1955-56, I think), were
the high point of construction and finish. They also used leather covering
rather than the vinyl of later models. The Technikas kept evolving, so
each subsequent model had clear advantages, but “fit and finish” did not
improve after the mid-50’s, and may have declined somewhat.
Myron
