to choose!
Andy
- 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
> P
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 tw
I am grateful for his republishing activities; however, does he manage to
obtain valid copyright on his books?
(I have sometimes wished for some addendum to copyright law so that if
the holder is not making the material available that the copyright looses
its validity. There are certainly argumen
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 know
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
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 attaching
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 t
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
ha
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.)
I have considered subscribing, as you recommend, to View
Camera. Unfortunately the keeper of the magazine is a little rigid and
refused to send it by surface mail, instead taking first class (and maybe
air mail) at a major increase of cost to the European subscriber.(First
class rates are com
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 is
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 hav
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 m
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 the
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:
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
watt
I didn't notice 2x converters and extension tubes which include helical
focusing; which brands and types must we find. In contrast, typical 135
mm telephotos permit around 12 mm of focus adjustment.
Bob
At 20:20 15.01.03 +0800, you wrote:
Or sometimes el-cheapo 2x converters, or extension t
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 buy
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 ex
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
overco
One further word should be added; measure the distance from one of the
flange surfaces to the iris. The iris should be at a particular location
relative to the glass and you should try to reproduce this with reasonable
accuracy. Because of the standardization mentioned below and a tendency
t
Regarding the suggestion below, maybe the textured surface could be fine
sandpaper sprayed with some non-stick coating or else PE sheet with the
impression of sandpaper to roughen up the surface. Perhaps a coat
of wax will doe the job of separation agent..
Another hard- to- stick- to surface is p
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
The business about monochromatic light light applies mainly to specific
classes of lenses to which PROCESS lenses do NOT belong! Process lenses
will be not only achromatic but even the next step better. An achromatic
is corrected so two colors (wavelengths) come to the same focus. The APO
pr
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 leath
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[EMAIL PROTECTED]
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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 wo
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 t
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. Ve
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 oft
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
patie
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
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 failing
It would not be hard to do without a microprocessor, but it is almost
surely easier when one is used (very few components but some programming
instead. The pure hardware method would require a fair number of
components, though by resorting to position sensitive switches to sense the
end of tr
Try finding some litho plates; these are thin aluminium (often, but not
always) of a harder kind.
Anodizing does take some slightly threatening chemicals, but nothing really
bad. A weak solution of battery acid will suffice. Dilute to about 1 %
acid in water. A more serious problem is getti
ght...
>I am still stuck with the max steps/s. I really have to take down
>each motor specs and calculate the gear for best torque/speed ratio.
>It's tricky :o) !
>
>Sometimes I think I'm real nut trying to realize my dream !
>
>Cedric
>On Tue, 24 Sep 2002 23:25:
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 ste
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
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
aberration
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
__
Has anybody looked at the backlights for laptop LCD s for this job. Older
models (laptops) can be picked up fairly cheaply, and maybe for free if
something else died than what you need. You do have to be careful; the
power supplies for cold cathode backlights can deliver much voltage and
con
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 makin
Are you sure you want to make an iris diaphragm? The thin metal leaves are
easy or hard, depending on your method. I would etch them out of metal
foil. However, there are pins at the end of the leaves and at one end the
pins run in tiny slits. You will have fun making all those slits, thoug
Are you sure? I have seen furniture made with plywood, showing the ply
structure. It was attractive. I would tend toward dovetail joints. They
are attractive and strong, though not exactly easy to do. Of course, taste
is an important component in these things.
Bob
At 07:49 27.08.02 -07
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!
>
&g
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
You are correct! And I am wrong. I am sorry for any confusion I have caused!
The is no movable pressure plate in Large Format film holders and the film
is just inserted so it lies against the large flat back plate. It is
indeed held by ridges I mentioned and by the hinged flap.
My problem i
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.
I have inserted some comments below at the ""
Bob
At 14:31 17.08.02 -0400, you wrote:
>OK on the non-glare framing glass not making useful ground glass - I think
>it's useless for framing too :O)
>
>I understand the concept of the spacing of the emulsion relative to the film
>h
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) t
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
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 f
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
?
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 p
Please see below!
At 01:23 09.08.02 -0700, you wrote:
>Hi john!
>
>Very helpful. I don't have a problem getting a Nikor lens. i was under
>the impression one of these large lenses would put out a lot more light
>(f 1). I did realize the plastic elements would probably block the UV.
#
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, so
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 ha
A wire frame should be quite accurate provided the hole at the eye-end is
not too large. You don't have parallax correction but many viewfinders do
not and those which do need input about the distance of the object to be
photographed. You would have to input this manually because you do not h
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
l
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,
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
met
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
diffraction-
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
>shutte
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
>A few additional words might help here. The single curtain with a fixed
>width slit cut in it is rare in modern cameras. This shutter type
>has the problem of needing a curtain moving at a constant speed over the
>film to obtain a constant exposure. Making such a shutter is possible but
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 not
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 wh
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]>
>
>
Whether the threads are too fine or not depends on some details. If you
are focusing on ground glass it doesn't make too much difference how many
turns are needed to reach focus. If you want a scale, exceeding a single
turn is awkward unless you invent a trick.
The threads on almost all len
There is somebody offering an Aero Ektar at ebay
http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=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 G
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
probl
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
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
>enlarge
I think that if some element is a problem, it is thorium. It has been
used, but is not exactly a common component in glass, though some military
optics are easily available with thorium.
I cannot find any radioactive isotope in a table showing what is in natural
barium. The element is often
> 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
I don't know about modern methods, but there was a time when eyeglass
lenses were finished to a much lower standard than those for precision
optics. This is no surprise, less quality is required and it is not
trivial to polish lenses which do not have spherical surfaces (and the ones
for thos
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,
Try looking in the Melles Griot catalog for data. I believe their shutters
are identical to the ILEX models except for the label. (They look identical.)
I doubt that you will find a schematic unless you have a well-placed friend
or construct one from a controller you have or can borrow (ther
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 1
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 bou
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 th
Who knows how to paint this so the paint survives lengthening and
shortening the bellows?
Bob
At 10:47 15.11.01 -0800, you wrote:
>in addition to the dryer vent material - they make a
>duct material that comes in 6, 8 and 12 inch sizes. A
>2 foot length will compress down to an inch. Heating
At 01:21 15.11.01 +0100, you wrote:
>Wayde,
>I remember my father, an inventor with ca 25 patents in several countries,
>once saying to me - you will never replace bellows with someting else...
>it's so old and yet the best. Me too, I tried with balloons... no way! The
>best I made were telesco
I doubt the need for optical glass for this application. You do need some
good quality glass, however. If I were doing it I would look at cheap
picture frames, perhaps the "frame-less" kind, and select one without
defects. If you can get your hands on some old scientific glass plates,
devel
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:
___
Cameramakers maili
The idea with a gear is the same except for using an "unofficial
ratchet". The end effect is similar except real ratchets are liable to be
made from hardened steel. If your loading is light the gear should last long.
Don't worry about the seemingly small sizes, especially if you can do it on
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 a
I think I have such a thing from an old aerial camera. If no alternative
offer appears I am willing to make a slight effort to find it for you. The
trouble is that shipping from here is not cheap and any alternative nearer
you is a better choice.
I have seen such parts in copy machines so if
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
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
___
Cameramakers mailing list
[EMA
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]>
>To: <[
Would it not be easier to mill the teeth (router) with a shaped cutter and
just some device to advance the cutter by one tooth spacing after each row
of cuts. Making cutters should be quite easy. The rack can have straight
sided teeth and it is not hard to make an involute cutter for the
ge
And I have encountered types with glass in front of the platen, so both
possibilities are in use.
Bob
At 10:08 24.10.01 -0700, you wrote:
>William and George,
>
>I don't have any direct knowledge of any nine inch roll film cameras,
>but the 5 inch cameras I know of all have vacuum film platens.
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
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 te
I would love to see a list of the lenses suggested for this
application. Maybe I can find one!
Bob
At 10:55 22.10.01 +, you wrote:
>Hi,
>A little while ago, someone posted a question about astro cameras, looking
>for pictures, plans, etc.
>
>While there are no plans per se in this book, H
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
I seemed to have missed the original posting on sources of stepping motors
but there are a couple I have not seen mentioned (I do not know the purpose
so I cannot judge whether these following give the right kind of motor.)
Floppy drives often have stepping motors to move the heads. The ones i
If you really want to go the vacuum back route, maybe a pump from a blood
pressure measuring device can do the job. I have never taken one apart but
most likely one could be modified to make vacuum instead of pressure. The
ones I have in mind are automatic; you put it on the arm and it does t
I doubt that you can get good results with a vacuum back on 120 film. You
want the film to be flat, not the backing paper. I have never used 220 but
if I understand correctly it lacks the paper behind the film.
There is an obvious solution, 70 mm film. It may be a slight problem to
get as w
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