I have made a lens board for a Linhoff iii using just sheet brass. It struck me
as being unproblematic, using just hand tools.
Best regards
Laurence Cuffe
On 4 Apr 2019, at 14:56, Zack Widup <w9sz.zack@xxxxxxxxx> wrote:
My favorite source of aluminum (and other metals):
http://www.onlinemetals.com ;<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
<mailto:goch@xxxxxx>> wrote:
What I don't know is about the lens boards, and really haven't found a
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
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