scanner at the start. In truth, the sizes do not vary
all that much!
Dr. Robert Mueller
Institut fr Festkrperforschung, FZ-Juelich
D-52425 Juelich, Germany
phone: + 49 2461 61 4550 FAX: + 49 2461 61 2610
email: [EMAIL PROTECTED]
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re tough, but the black 2850 FT contains fairly hard
particles which ought to increase resistance to abrasion compared to most
unfilled finishes.
Please experiment to find the best solvent (others will almost certainly
also work) and amount of thinning.
Good luck!
Bob
Dr. Robert Mueller
Institut f
being used.
Bob
Dr. Robert Mueller
Institut fr Festkrperforschung, FZ-Juelich
D-52425 Juelich, Germany
phone: + 49 2461 61 4550 FAX: + 49 2461 61 2610
email: [EMAIL PROTECTED]
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[EMAIL PROTECTED]
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the
cloth, or better, impregnate the cloth after the bellows layers are bonded.
More than a day long wait is asking for trouble.
Bob
Dr. Robert Mueller
Institut fr Festkrperforschung, FZ-Juelich
D-52425 Juelich, Germany
phone: + 49 2461 61 4550 FAX: + 49 2461 61 2610
ema
in modern urethane, but I have never
heard anybody admit there has ever been a problem so I don't expect any
assurance it will never happen again. Until you have that assurance,
consider the sinking feeling when you find your work reduced to a paste
impregnated bag by decay of the cement.
Bob
be found. Silicone
will absorb some solutions and might let in dye, but will such treatment
shorten the life? I have no idea, but brown is probably not all that bad
for absorbing light, and better a tight brown seal than a leaky black one
or one with a short future.
Good luck.
Dr. Robert Mueller
verify. Sorry!).
Bob
Dr. Robert Mueller
Institut für Festkörperforschung, FZ-Juelich
D-52425 Juelich, Germany
phone: + 49 2461 61 4550 FAX: + 49 2461 61 2610
email: [EMAIL PROTECTED]
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/cameramakers
Dr. Robert Mueller
Institut für Festkörperforschung, FZ-Juelich
D-52425 Juelich, Germany
phone: + 49 2461 61 4550 FAX: + 49 2461 61 2610
email: [EMAIL PROTECTED]
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the pinhole
diameter. You can measure a needle with a workshop micrometer. You could
also puch the needle into an existing hole until it stops and measure in
the same way. I once made a gauge for small holes working this way,
following a design known for decades if not centuries!
Dr. Robert Mueller
If nobody else comes forward, I have a bunch of data, but they would best
be faxed. If no better source appears, please let me know.
Bob
At 09:38 03.09.01 -0700, you wrote:
Let's expand this just a tad. I'd like to put a table of standard
film holder dimensions (4x5, 5x7, 8x10, etc.)
Is it really possible to buy shim stock 0.0001 to 0.0005 at hobby shops in
the USA? Is there somebody who would please send me information on prices
and maybe even offer to mail me some if I send the cost of postage and the
goods. I see no reason why more is needed than putting it into an
Thank you, Barry. This is what I suspected (feared?) In fact, it is
possible to buy metal foils in narrow widths and about =.0001 inch thick,
but they will be rather expensive and I doubt if they will be appearing in
hobby shops. However, if somebody really has a source of inexpensive
Yes! Absolutely correct. However, for a hemisphere you get 90 degrees
coverage at the corners. It is already a bit of a wide angle; if I
remember correctly, one usually defines a normal lens as one with focal
length equal to the length of the diagonal. Here we have the focal
length at 1/2
I insert some comments below;
Bob
At 10:07 22.10.01 -0400, you wrote:
OK. Here it is. Is this what you are interested in?
http://www.rit.edu/~andpph/text-conical-strip.html
Sam
Hello!
I could use some input. I have an idea for a rotating 4x5 slit camera.
The plan is to have the camera
How about just having a glass about a centimeter is front of the film. Then
pressurize only the chamber between film and glass. The bellows is free of
pressure and the volume is far smaller, yet dust on the glass will be far
less obvious and the glass will not be touched so there will be no
At 05:27 23.10.01 +, you wrote:
Why not just put a glass about a centimeter in front of the film. Dust on
this glass will make a very diffuse shadow except possibly at very small
diaphragm openings, so you are unlikely to notice it. Conversely, the
volume to be pumped is smaller than
it looks like the list is myself
and Phil McCourt. I'll keep the list informed of the plans and as I get
them into Power Point I'll post it on my website so you all can see what I'm
doing.
Dan Rhoades
www.rhoadescameras.bizland.com
- Original Message -
From: Robert Mueller [EMAIL PROTECTED
One other thought; I do not do any high class woodwork but my father
did. I can imagine using the cutters I just described to make teeth by
hand in the good, old fashioned way I saw as my father made moldings.
Bob
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You are right, and not quite so right! The trouble is that the correct
rack for a lantern pinion is a cycloid but an involute rack has
straight-sided teeth, and there are a lot to cut. Conversely, A lantern
pinion might just be the way to get the strength in the pinion teeth.
Bob
At 15:53
Several is a different story! Why not make one. A simple design I have
seen depends on some bearing balls which run on little ramps. There is a
drum and a disk inside it. The ramps are cut into the edge of the
disk. For one direction of turning the balls roll up the ramps until they
jam
Try
http://www.horology.com/hoc-susu.html
for some sources of parts. I saw both LaRose and Selva there. And others
I suspect both have Internet sites, but I have not checked that.
Bob
At 08:20 31.10.01 -0800, you wrote:
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Cameramakers
A few weeks ago I broke down and bought a pencam as a quick and dirty way
to record things for the Internet and simply whenever I was underway (I
used to consider a camera working on film for the job but the instant
readout appeals to me.)
Well; I was lucky; the images were not so good and
It was asked where one can buy thin leather for bellows; I must admit it
has been a few years since I bought there, but Tandy shops did have
it. These seem to be moderately common; however, maybe they have all
disappeared since I was there.
It is likely to be a little thicker but I have
Why must the viewfinder optics for the eye be shared with the laser? Just
put the laser below or above, though as near as possible. Of course.
magnification can be included. With separation you have no danger to the
eye except maybe if you measure the distance to a mirror!
Bob
At 20:09
If I were doing this I would not use a Metrogon! I like the Metrogon and
own three 6 inch ones, but I doubt that it is the best lens for the job I
understand you want to do. Let me try to explain.
Wide-field aerial lenses are designed to achieve various properties over a
wide angle of view,
In short, the small, inexpensive, gear-reduced, reversible, 3-wire
capacitor run motor is by far the simplest way to go.
Have fun, bye, sid.
Perhaps, but almost as easy is a DC motor with a gearbox. The beauty of it
is the ease of reversal (reverse polarity of power) and
To any and all,
I favor using the original header for these messages, provided it describes
the main content. But does Cameramakers Digest . really give any clue ?
Bob
At 21:22 20.02.02 -0800, you wrote:
Very interesting. Could you send me an image of the lights adapted as an
enlarger
If you do not mind having the lens rotate (annoying but not unbearable) you
can try some plumbing components and especially drain components. They
have a fine thread on thin walled tubes of brass (maybe chromed for
Beauty (if you like that sort of appearance on you photo stuff!).
Bob
PS
It has been a long time since I lived in the USA and so I do not know all
the possibilities to fulfill this suggestion, but here I see very cheap
lenses for 35 mm cameras now and then. The condition may be bad, but if
you want the mount and the glass is bad, who cares!!! There is a
There is somebody offering an Aero Ektar at ebay
http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItemitem=1334394605
I believe anybody who can read the German text might enjoy the
information. Indeed, you can probably guess enough to make sense out of
the numerical values even without reading
Thanks; it always looked so formidable that I was frightened off. If it
is hardly worse than a single start thread, it is well worth
considering. I appreciate the encouragement, and still worry, but less!
Bob
At 21:03 24.02.02 -0500, you wrote:
Re;Barry Young [EMAIL PROTECTED]
The
Dear Barry,
Perhaps you have some advice on getting the depth correct. The obvious
solution is wires, for the outside thread (except for those who are lucky
enough to have a thread micrometer.) How is the mating inside thread
monitored for depth? This is the operation which was my worry
Well, yes, almost!
I have done many of the steps in making a shutter to be controlled
electronically. Indeed, there is an AutoCad file of the blade shape and
I also had the electromechanical parts up and running on the blades of an
old Ansco lens. This was a two blade type but they are
In my computer! But I can send you the file. Please understand; it is
ONLY a drawing of the blades for use in etching to cut out the thin pieces
without damage likely to come from mechanical cutting methods.
I do have the mechanical driver but that was done without AutoCad (I did
not even
You do mean 76 mm diameter, I believe. That is already pretty big but
sounds about right for F4.5 in 10 focal length.
Bob
At 21:38 20.03.02 -0800, you wrote:
Hi there, ho there!
I've just picked up a set of Ilex Paragon Anastigmat
4.5/10 (254mm) elements without a barrel or a
shutter... So
I am not sure I understand the comment Betcha they weren't polished to as
good a figure If they were not well figured, how did they reach
diffraction-limited performance (as has been reported in previous postings
in this series)? Conversely, who needs the better figure if
I just saw the very nice site on the construction of an 8x10 camera and had
a suggestion. In the text it is mentioned contact cement was not
successful as an adhesive. I am not too surprised because this stuff is
horrible to apply as a thin and uniform coat using a brush or other obvious
Yesterday my newest issue of Engineering in Miniature arrived and it
contains an article of probable interest to some readers of this group. It
is the first installment of The Korekta 5x4 Flat Bed Camera. Because
this magazine is not much oriented toward cameras as construction projects,
Just a question based on the statement below about litho film. Litho film
lacks tonal range when it is processed in litho developers. How does the
range look when processing is in more conventional (lower contrast)
developers? It may still be poor if I am right that part of the secret of
Dear Pierre,
Where are you? I assume either France of Canada, but maybe it is somewhere
else. Anyway, I have an ancient book giving these dimensions with a
drawing. If you are in Europe I will mail you a copy of the appropriate
pages. If you are in North America I am sure somebody there
Look at Surplus Shed for military lenses. I would look for something with
larger aperture (not a Metrogon) and normal viewing angle.
You might also look for projection lenses of the kind used for opaque
projectors (I doubt anyone makes these anymore and probably few persons
still use them,
?
A proper lens takes the light coming from the object (the film in this
case) and projects it in a way such that all light coming from a single
point, whatever its direction of travel, will end up at a single
Diffusion glass will do the job as well but with the cost of considerable
light loss, which might be important when exposures are getting to look
like hours.
Bob
At 08:49 09.08.02 -0700, you wrote:
Another thought... If you are exposing for a long period of time the
position of the
Does it really make any difference whether the plate is made of glass or,
say, Mylar? The substrate can almost surely tolerate higher temperatures
than the emulsion. Mylar holds up even at 200 degrees C. I would make no
bets on gelatin at this temperature.
Can't you use a variety of films
http://www.gigabitfilm.de/download/datasheet_small_format.pdf
http://www.gigabitfilm.de/html/english/technical_information/descriptions.htm
Some of you enjoy pushing the art of photography as far as possible and the
above pages might provide help if you desire maximum sharpness for your
photos
The desired location for the ground glass is easy to state. The rough side
should face the lens (normally, anyway), and lie at the same place as the
emulsion of the film during the exposure, while composing and
focusing. For normal film holders you must then measure (or look up
somewhere)
Thanks --Michael
[EMAIL PROTECTED] for the up-to-date data. My source is ancient and lacks
tolerances (I think!) However, I question one detail below:
The ANSI standard for the depth of a standard 4 x 5 inch film
holder is 0.197 plus minus 0.007. Most film has a base
of 0.007
The dimensions of the film holders are valuable information to anyone
making his own camera and it would be nice if the group had them available
to all. They are published (up to 8x19, at least) as ASA data sheets but
these are not all that easy to get. Is there any chance to post them for
22.08.02 -0600, you wrote:
On Thu, 22 Aug 2002, Robert Mueller wrote:
to all. They are published (up to 8x19, at least) as ASA data sheets but
these are not all that easy to get. Is there any chance to post them for
all?
Most definitely yes!
Which really boils down to two different questions
Dear Joel,
I did once find such a diaphragm and you will never guess what it was
doing. It was an aperture for a fan. Please do not ask why it was done
this way. I doubt that it is a full 2 feet in diameter, but more than 1
foot is possible. In any case, on such a large scale I agree
Does anybody have an idea about how much the price is for using a Metrogon
in one configuration versus the other, i.e., with or without the proper
center filter? I do not refer to loss of uniformity but degradation of
the resolution or MTF values.
Bob
Thanks for the advice on the center filter for the Metrogon. I actually
had a different problem in mind. As I understand it a piece of flat glass
adds spherical aberration. Someone in this group reported that the
Metrogon was calculated with this in mind by including compensating
I am not sure I understand the need for a full spectrum source for black
and white though I agree one must consider the spectrum with more care for
color work.
If you are not using multi-contrast paper I would think a bluer lamp would
look good and a lot of inexpensive fluorescent lamps ought
If you drive stepping motors with a pair of 90 degrees out of phase sine
waves (sine plus cosine) you will often find the motion to be much
smoother (I assume you would have 2 phase motors). I suggest selecting
motors with finer steps, 200 per revolution or more. I have seen 400 to
500
Please look at the old floppy drives. The motors are typically almost
cubes 40 to 50 mm on a side. (There are exceptions of various kinds so try
again if the first one you look at is not suitable.)
I have a few nice steppers which are flat disks less than 20 mm thick, if
my memory is
From the photos I cannot judge but the electrical thing on the back of the
lenboard is probably a shutter operated by a rotary solenoid, most likely
made by LEDEX. Instead of a linear motion the shaft turns with
application of an adequate voltage. It might operate something else than
a
While I was in our shop today I recalled the thread on dark slides and
began to wonder whether a source of metric material could help anybody. I
can probably get this and I am willing to do so if the person desiring it
is willing to pay the price of the material and shipping and has the
It would be tempting to use just any light oil to treat the AE-1 squeak but
normal mineral oils have a troublesome property; they wander, crawling over
the surface. This takes the oil away from where you want it and deposits it
somewhere you definitely don't want it. Clock and watch oils
Thanks!!
Bob
To cure Canon A-series squeal, remove front apron (4 screws), remove
top left lens mount screw insert oiler --- deposit one drop of oil
where the flywheel contacts the nylon gears.
Paraphrased. Better if you can locate Joe's book and take a look at the
pictures. Very
Dear Peter,
When I last checked the USPS prices they were a bit over $18.00 for the
first pound on a package with air even a little cheaper than surface. The
small packet rate is lower and for a bit of oil maybe first class is the
best choice. Actually, you probably have little motivation
Dear Peter,
You may not detect it but I am an American who has been in Europe for a
couple decades now. I have little respect for the USPS. There was a time
when it was a proud and effective organisation as seen by the user; today
it is an imitation of a private company which combines the
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Sorry; I think I just sent an empty posting!
Frequently when repairing medium format and 35 mm cameras one must lift the
leather to get at screws. Typically there is corrosion under the leather
and I assume it is either chemicals in an animal skin or chemicals used to
process the skin to
I am not sure this is possible but you can coat the stuff with thin layer
of silicone of the sort used for sealing bathtubs, aquariums
and... You can thin it with a considerable amount of mineral
spirits (it takes a lot if you want to brush the result). Add
enough carbon black (I had success
You are right; a home-made meter could be as good, and with little extra
effort, better than a commercial model. It would not even be too hard if
you do not insist on too many bells and whistles. I finally bought a
commercial one and modified it to live without mercury batteries and to
Why don't you look at an over-the-shoulder (Overhead) projector.
Then make photocopies as transparencies. The image will be much
brighter. Opaque projectors are extremely wasteful of light and the
overhead kind are far better. Today photocopies are fairly cheap,
even in color. Meanwhile, I expect
This is possibly a help but I admit problems! I just returned from London
and Jessops Classic was offering old (low grade) 35 mm lenses for one pound
each. Your cost would be almost all postage. Some member of this group
might buy a bunch and ship them to anyone needing one. ( I didn't
You need conversion factors from watts to lumens. Those depend on human
eyes which have a great variation of sensitivity with wavelength if you
measure incident light in watts. You can find plots or tables of this,
but at the most sensitive wavelength it is somewhat above 600 lumens per
It depends how far into the UV you go. Many glasses transmit a fair
amount of near UV.
Which wavelength is needed for this process?
Bob
At 07:15 01.02.03 -0800, you wrote:
If I
remember right, UV doesn't like to pass through GLASS.
Gene
- Original Message -
From: DONALD MILLER
To:
Further comment, following my previous one! The below listed wavelengths
do pass through many glasses. Focusing will be somewhat of a problem,
though you might be able to something similar to what is do for IR
photography; find the right shift of focus, do it in the visible and then
make
There is a second reason for wanting a shutter, namely, certain (many)
kinds of discharge lamps greatly dislike being turned on and off very
often. The lifetime can be drastically shortened. Needing a
ballast and a lot of UV strongly suggest these are discharge lamps.
It is worth checking the
Certainly if the material has appreciable sensitivity in the visible range
the user would be advised to put as much light as possible in this range,
where the optics are properly corrected.
Bob
At 01:04 02.02.03 +, you wrote:
Aren't there other issues concerning the image quality that
I would much appreciate information on how I can contact this fellow
regarding a lens making problem. May I have an email address, telephone
number, or even his postal address? He might be just the person to amke up
something for us!
THANKS in advance.
My email address for the information
I expect you will have trouble if you want a camera taking a full roll of
16 mm film. It will probably be pretty big=heavy. However, if
you can carry one and find one with single frame capability, you can very
many photos on a single flight. (Not every movie camera offers single
frame ability.)
modification.
Bob
At 00:31 05.02.03 +0300, you wrote:
Robert Mueller wrote:
...
There were various cameras taking short lengths of 16 mm film,
from Minolta, but I believe also Pentax and Lomo.
Not LOMO but Kiev. Kiev 30 or Kiev-Vega models might be what you
had in mind. Those came from
I have seen photos of reels for long lengths of film in which it was wound onto
a sort of drum, except the drum was just a series of thick wires arranged
parallel to the axle and forming an open cylinder. The film was just wound
onto this as a helix (like the thread of a screw). You will have to
I would just illuminate a piece of paper with the flash and then look
through the shutter at that paper while the flash (shutter) is fired. You
should see the full opening for a fleeting instant.
Bob
At 23:12 19.02.03 -0500, you wrote:
I tested my Packard shutter with the 2 wires by
To all:
Perhaps my email program is more generous than what you have, but for
every message which arrives from this group I have quite a lot of
data. I reproduce a sample below. You will notice that I have
the email address of the person submitting the message, in this case that
of Jim himself,
Unlike patents, copyrights have very long lifetimes, though I hope an
expert will define the rules better. In the case of patents in the USA, I
believe the life is 17 years plus the possibility of a renewal for the same
length of time. I believe the duration is country-dependent.
I don't
As was suggested in an earlier posting, there is no reason to use the
Polaroid holder for normal film. There is a standard type of holder which
you should be able to obtain in any shop knowing anything about large
format photography. You should have several of these because each holds
only
- Original Message -
From: Robert Mueller [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Saturday, March 15, 2003 4:29 PM
Subject: Re: [Cameramakers] Polaroid 545 or 545i
As was suggested in an earlier posting, there is no reason to use the
Polaroid holder for normal film. There is a standard
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