Advertisements

Tag Archives: tool

Vintage/ Antique camera repair/ restoration tools

Kyphoto.com is one of the most reliable and resourceful sites for camera repair information. They provide a list of useful camera repair tools, which are asked by many people.

Are you a DIY guy trying to fix or rescue your own precious cameras? If yes, there are the tools that you need.

Screwdrivers
Niwa brand drivers are our favorites because they have big handles and the replaceable tips are very strong (but it doesn’t mean they are unbreakable!). The T-handle is a nice addition. A Sears set of six (4 slot and 2 phillips in a blue plastic case) is handy to keep around when a special size blade needs to be ground. This set is cheap and made of good, hardened steel.
Pliers
Don’t think one can ever have too many different pliers. Sears has a set of 4 mini pliers that is a good start. A tool should be comfortable… A set (round and pointed nose) of 4″ Visegrips are excellent for holding parts during filing or precise bending. A set of cheap fixed tip snap ring pliers with the tips filed to fit pin face screws. Only use this if the screw is so tight the friction screwdriver won’t remove it. The plier set you see in this picture was bought at Sears for $9.99.
Tweezers
Plastic surgical tweezers are the best for general parts handling. They are big and stout. But a set of metal, straight and curved, are sometimes required.

Lens spanner
Depends from person to person and job to job if spanners are necessary. Especially on really tight lens rings they are invaluable. The replaceable tip ones are best. Also S. K. Grimes makes an excellent looking spanner.
Needle Files
A cheapie set of 10 different cross-sections has worked fine.
Set of Batteries
If I had a nickel for every time a friend has shown me this “broken” camera and all I did was put in a fresh battery… well, I’d have at least a dollar! Seriously, keep a set of various batteries around. I have a short length of wooden 2×4 with holes drilled in it to organize my batteries.

Filter Ring Remover
Most camera shops carry cheapie filter ring removers. The big plier-like ones seem best. I don’t have a set of these big, nice…expensive…ones, but they are on my Christmas List.
Head Loupe
Next to my Tee-handle Niwa driver I use this the most. Could be my aging eyes?? I use it in diagnosing parts or checking lens element cleanliness, as a face shield while making parts with the rotary tool, any time I solder… gosh, all the time.
Rotary tool
Sears offers a nice 5 speed model. When you advance into making/modifying parts this tool will be your closest friend. I’m amazed that of my numerous bits I only use about four 99% of the time. Cutoff wheel, pointed grinding stone, rasp (looks like an end-mill) and a small ball tipped cutter. The first three are 1/8″ shank and the last is 3/32″ shank.
Soldering Iron
I use a 45 watt Radio Shack pencil type plugged into a variable temperture control unit. My favorite tip is a spade type I bent to about 45 degrees.
Friction screwdriver
Make from a short length of round wooden dowel (or broom handle). Just glue a piece of flat rubber on the end. A couple different diameters is handy. These are used mostly for removing the ring around wind levers. I use it even if the ring has grooves.
Crochet hooks
Makes excellent spring hooks and probes. I use a set consisting of US10, 12 and 14. And I have an extra bent US10. The 10 is especially useful for spinning off lens rings after initial loosening.
Artist style paintbrushes
For internal cleaning… Flat ones are better than the pointed.
Toothbrush
Exterior cleaning.
Rubber pads
For loosening anything you don’t want to scratch…like everything. Start collecting various soft rubber pads. Anything can be used: furniture foot pads, sink stoppers, door stops…anything. A few sheets of soft rubberized cloth (dental dam) works well.
Tool holder
Don’t know about you but my desk gets cluttered with tools when I’m tinkering. The best thing I have found to organize the tools currently being used is a 78 cent plastic drill bit holder. It is made to hold 26 bits from ½” to 1/16″. Holds everything from pliers to screwdrivers to…well, everything I normally use. Alternately a piece of 2×4 with custom drilled holes would be perfect…but for 78 cents, I can be lazy.
Parts tray
A very necessary tool of organization! You can spend money on a store bought tray or… got a buddy that plays golf? or play yourself? The plastic egg crate-like containers that some brands of golf balls come in are near perfect. See thru is better…
Big, strong magnet
To find and pick up small parts you WILL drop.
Machinist’s dividers
Best for pin faced screws like shutter speed dial screws, self timer screws, etc.
Wooden chopstick
To insert in between the fork of the rewinding shaft to unscrew the rewinding knob. Does not scar paint as opposed to the normal screwdriver handle.
Toothpick or inkpen
Once the retaining ring is loosened, unscrew the remainder with one or both of these two items. Inkpen (no ink, of course), if extra strength is needed. Toothpick, for smaller notches and good for depositing small drops of lubricant or glue.
Film can
Need to store a bunch of little parts? If you shoot Fuji film like I do, you can write the camera name on the side of the white container. I have three or four from off brand film that are clear. They are the best.
Film cans
If one is good, then two is better and seven is perfect. Six empty film cans fit perfectly around a center can. Rubberband these all together and you have a great place to set those opened tubes of glue, thread lock, teflon oil, epoxy, etc. Also great for thicker tools like the friction screwdrivers and small butane torch shown. A ton of mini pliers will fit in them too.
Windex
Excellent for cleaning lenses but I use it for cleaning everything on the camera exterior.
Pliobond
For regluing leatherette mostly but works fine holding curtains and curtain straps to their shafts. When gluing curtains and straps clamp tight for best bond. The nice thing about Pliobond is that is doesn’t dry stiff.
Ronsonol
Good for dissolving old grease and flushing out dirty mechanisms. Caution: Ronsonol is very flammable…duh, it is lighter fluid. Coleman campstove fuel works fine also but stinks to high heaven.
Teflon Lube
Use sparringly on pivot shafts. Apply with the tip of your smallest slot screwdriver. Radio Shack carries a couple different types in handy tubes.
Moly grease
Thick molybdenum disulfide grease. Good for high surface stress areas or use as focus helix damping grease. Also very useful for holding aluminum/brass screws of old Kodaks to your screwdriver. Just apply a small ball of moly on the driver tip and stick on the screw. It’ll stay stuck there until you start the screw.
RemOil
This is gun oil. I use it as penetrating oil. It can be a mess to use but it frees shafts and pivots well. On older cameras I usually flush with Ronsonol after the parts free up then blow everything dry and apply Teflon lube to the pivots. On newer cameras made of harder steel parts I skip the Teflon lube and run dry.
Acetone
(in some types of fingernail polish remover) Use to unstick stuck screws.
Graphite
Get the finest grain size you can find. I use graphite as a manually applied plating. I massage it on contact surfaces until the color slightly darkens then blow out all stray graphite. Very good for aperture/shutter blades.
J/B Weld
Can repair most broken parts that don’t see high stress.
Kleenex
To clean lens elements. My favorite technique is to fold the Kleenex in small squares and hold with round tipped locking tweezers. Do not touch glass with tweezers nor apply pressure. Wipe in circles, do not scrub. And change the Kleenex if ANY dirt particles can be seen on it. These particles WILL scratch the glass!
Paper towels
Exterior cleaning and as a placemat for the camera to protect both camera and desk from scratches during assembly/disassembly.
Washcloth
I prefer an old washcloth in lieu of the paper towel as a placemat.
Paints
Micro-Tools sells several paints and coatings that sometimes even match the camera color!
Can of compressed air
An essential cleaning tool. An air compressor set at about 40 psi with a pencil tip is best and by far cheapest but my wife won’t let me bring the garage compressor in the house.
Dial vernier caliper
To measure things… What else can I say? Generally only needed when making/modifying parts.
Multimeter
Circuit testing. And if you have a digital, one check out the shutter speed tester you can make using it. A description can be found in test equipment section.
Dial Indicater
Like the dial vernier, not used very often.
Advertisements

Photographic Metering Technique Introduction

Source: Index page.

 

Ever since the beginning of photography there was the question; “how do I get my photographic correctly exposed?” It does not matter if it is material in the camera or in the darkroom.

For taking pictures outside, one could use timetables telling us , depending on location, season and time, how to expose our film. Later people invented the exposure meter called the actino meter and also the extinction meter more or less based on comparison of density but these meters are outside of the scope of this website.

Finally in the late twenties and early thirties a way was found to create photo electric sensors sensitive for visible light. When exposed to light the sensor generated a voltage, enough to drive a galvanometer telling us the amount of light measured.

The Photoelectric exposure meter is a product representing almost  100 years of scientific research. Already a lot is written about the photoelectric exposure meter but history here: actually three discoveries lie at its foundation. In 1839 a French scientist , Edmond Becqurel discovered that light increased the output of voltaic cells when it fell upon platinum coated electrodes. Thirty-four years later Willoughby Smith, a telegrapher then working in the Azores, noticed that the selenium in his line-testing instrument changed in resistance to current when light fell upon this element. In 1887 Heinrich Hertz, a German scientist found that electrically charged particles or  electrons were shot  off certain substances when exposed to ultra-violet rays. Since then a lot of scientist are researching on these phenomena’s .

The basis for the photoelectric light meter was the selenium photoelectric sensor. It was long known the element selenium was sensitive for light but there was no proper method to manufacture useful sensors. Weston (USA) did a lot of research on these sensors and created a sensor for a photo electric light meter. However an additional power source was required. After improvements a cell was fabricated that functioned without the need of additional power (battery). When exposed to light, the cell generated a power. Weston, General Electric in the USA. Electrocell and Suddeutsche Apparaten Fabrik both in Germany manufactured photo electric selenium cells to be used in exposure meters.

The type that requires an external power source mostly needs a battery to drive the measurement electronics based on pe. a LDR, a CdS or a Blue photocell (photodiode). The light measured by the cell is processed by the internal electronics and fed to a read-out system. A lot of meters produced in the 60′, 70′ and the 80′ use a little Mercuric Oxide 1.35 Volt battery not longer available and is now banned because of toxicity and environmental fears. There are some alternatives to replace this cell but a 1.5 Silver Oxide cell is not an option.

The light measuring technique with a photoelectric light meter is actually very simple and does not need complex equipment. As an example we take a look at the Gossen Bisix 2 exposure meter for incident and reflected light. This meter consist of a number of parts.
– The reading scale with values
– The sensor
– The correction unit
– A meter element
– A ‘calculator’ disc
– A nulling system to set the meter at the zero position

The sensor or measuring element is actually an photo voltaic element which generate power when light falls on the element. it is an selenium element and used to produce first Gossen light meter in 1933. So it is a old system but still used for powerless light or exposure meters.
When light falls on the photo element the voltage is fed to the meter trough a correction unit to correct the power coming from the selenium element to the meter to give the correct read-out. The correction unit has to be calibrated to give the correct reading by a given quantity of light. To convert the meter from reading incident light to reflected light or vice versa a diffuser has to be set in front of the photocell. In this case this is a blind that can be shifted.

The meter element is mounted on a bracket that can me moved a little bit so with this construction the meter can be nulled i.e. the starting position can be set at the right zero value point with no light falling on the meter.
Measuring the incident light or the light reflected from the subject consist of pointing the meter in the right position with or without the diffuser and reading the measured light value from the reading scale. After reading the measured value, the value hast to be transferred to the ‘calculator’ disc by turning the scale until the red arrow points to the correct value. 

But first the right film speed has to be set on the scale by turning the little knob in the center of the meter at the right DIN / ASA value equal to the film used. After transferring the light value on the scale, the ‘calculator’ disc is set and the exposure time can be read from the  scale by selecting the required exposure time / shutter speed combination. 

Light

We use a light meter or an exposure meter to measure the amount of light. Actually both type of meters are basically the same instrument
except that the exposure meter has a extra device for calculating an exposure time and aperture combination for a given film speed. Light is measured in different values. In case of photometric measurement you want to measure the amount of light that is current in form of light intensity; lux, foot candle or candela/m2 Lx, fc, cd/m2, lxs, fcs and more. The light meter can be used for photographic purposes and for photometric purposes. In case of Photographic measurement you want to measure the amount of light that is available or reflected from the subject and set the camera accordingly to get a proper exposure. Setting he camera can be done by changing the aperture or the exposure time or both depending on how you want the exposure to be.

There is a difference in measuring light as it is coming directly from the light source (incident light) or is reflected by the subject (reflected light). Most meters cannot measure both types of light without making a change to your measurement equipment. For measuring reflected light the meter can be used without anything in front of the cell but when measuring the light source directly a kind of filter has to be placed in front of the cell. By Gossen meters, this filter is a part of the meter and can be placed or removed from the photocell. Meters that don’t have this mechanism are not made for measuring incident light but only for measuring reflected light. There is also a kind of light that is called ambient light. This is the light that is the light that is available at that moment without any intervention of the photographer in the form of a extra light source.

The visible light we use as a photographer is a very small part of a spectrum of electromagnetic energy. The electromagnetic energy radiates with a certain wavelength and intensity. Very much and detailed information about light and the physics of light can be found on Wikipedia.


Type of sensors

As far as known Gossen used 3 types of photo elements in their meters, at first they used the selenium photo element since the Ombrux, the first Gossen meter brought on the market in 1933. The advantage from the selenium exposure meters is that they don’t need extra power like a battery. A disadvantage is that they don’t live forever. Mostly the contacts wear out so these are insulated from the element and this stops the meter from functioning. (for the selenium cell see pictures further in this article)
After the selenium cell, the electronic world came with the CdS cell, this is a light dependent resistor or cadmium sulfide cell of which the resistance decreases when the light shining on the element increases.
The Lunasix was the first meter build with this CdS cell somewhere in the late 50’s or early 60’s. A fairly number of Gossen meters are build with kind of sensor.
The SBC cell was the next step for sensor elements of Gossen to build into their meters. This new cell the Silicon Blue Cell (SBC) is actually a fast photodiode and was integrated in the system exposure meter the Profisix. The exposure meters equipped with this type of photo sensor are recognizable by the SBC shield on the meter. Newer meters make use of more than 1 SBC as photo receiver. The Mastersix for instance has 2 of these diodes as sensor. The newest have even color corrected SBC sensors inside.

Selenium cell

Selenium Photo-Electric Cell
 

 

 

 

Selenium photo-electric cells
Selenium photo-electric cells convert the energy from the light falling on them directly into electrical energy. The advantage of selenium photo-voltaic cells over other cells is that their response is very close to that of the human eye; this makes them particularly suitable for use in light measuring instruments. Their efficiency as energy converters of the total spectrum is not as high as some other photocells, and so they are not used as solar cells. The diagram shows an idealized barrier-layer selenium photocell in section. The steel support plate ‘A’ provides the rear (positive) contact, and carries a layer of metallic selenium ‘B’, which is a few hundredths of a millimeter in thickness. ‘C’ is a thin transparent electrically-conductive layer, applied by cathodic sputtering; it is reinforced along its edge by a sprayed on negative contact ring ‘D’ and protected from damage by lacquering. The rear support of our photocells is protected from corrosion by a metallic spray coating ‘E’; this also improves the electrical contact.

Sensitivity
The average current into a low load resistance is given in the table. The active area of the cell comes to about 3mm from the edge – the diameter of the active area is thus about 6mm less than that of the cell in 
µA/lux/sqcmType B 0.07, Type M 0.03 and Type MFII 0.028

Megatron photo-electric cells are chiefly used for light meters, exposure meters, and other light measuring devices such as lighting controls for buildings. They are also used for a wide range of other instruments such as colorimeters, color temperature meters, smoke and turbidity measuring equipment as well as a number of devices such as flash actuators, smoke detectors and alarms, and aligning mechanisms for paper.

Performance
Each individual photocell is thoroughly aged, checked and re-checked being dispatched.
Cells have a more linear performance: when the load resistance is low, the cell is small, at low illumination intensities. Megatron manufacture two different types of cell, the Type M cell is also available with a special filter:

Type B Cells – general purpose, high stability and sensitivity, used for light meters, exposure meters, etc.
Type M Cells – are specially manufactures for photometry, as their spectral sensitivity, without the use of filters, closely matches the CIE standard observer,
Type MF II – uses a filter giving even better performance.
http://www.megatron.co.uk/selenium/index.html


The first Gossen electric light meters for photographic exposure and cine applications were made with the selenium photo-electric cell. These meters were equipped with a button for high and low light intensity reading.

The function of a selenium cell is actually very simple, when light falls on the selenium cell it generates some power. Because of this power, a current runs trough the circuit which activates the meter.
I did some measurement on a small meter and found the following values: The voltage generated by the photo-electric cell is 0 mV when dark and some 250 ~ 400 mV when light shines on the cell. The actual voltage depends on the type of cell. The internal resistance of the moving coil meter is about 1 Kohm so the current that runs trough the system is aprox. 250 mV / 1000 ohm = aprox 25 uA.

The sensor package consists of several parts, in this case (from left to right) the frame around the honeycomb lenses, the honeycomb lenses, a light filter determining the measuring angle, a metal contact frame with wire, the sensor, another metal contact plate with wire. The sensor contains a metal contact layer to make contact with the electrodes. The contact frame with the wire makes contact with the front (sensitive part) of the sensor. The metal plate behind the sensor makes contact with the backside of the sensor and also puts pressure on the package due to his spring shape. There are a number of websites on the internet with detailed information on how the selenium cell is made and how it actually works.

graph-Type B

This is an curve from a Megatron cell type B


CdS, Cadmium sulfide Cell

After the selenium cell, the electronic world came with the CdS cell, this is a light dependent resistor or cadmium sulfide cell of which the resistance of the cell decreases when light shining on the element increases. This change in resistance influences the current running trough the measuring circuit. A disadvantage is the need for an external power source like a battery while the selenium cell produces the power by it self due to light shining on the element. In the period when the CDS meters were build, a popular battery was the mercury cell with 1.35 Volts of power. However these cells are band because they contain a lot of mercury which is very bad for the environment. The cell that replaces the mercury cell is the zinc-air cell but this one has a lot of disadvantages like the very high price and short life time. Another disadvantage is the memory property of the CdS cell after the last measurement of bright light. This only takes a few minutes to disappear but the photographer must take this in consideration when doing the next measurement.

The Lunasix was the first meter build with this CdS cell somewhere in the late 50’s or early 60’s. A fairly large number of Gossen meters are build with this kind of sensor.

Giant CDS Cell Assortment

SBC, silicon blue cell

The silicon blue cell is the next step in the improvement of light measuring sensors. The photodiode is very fast, stable and can be color corrected to match the correct measurement of light. In some cases 2 photodiodes are used (Multisix, Lunasix F) to get a better result in light measurement. Sometimes a combination of a photo diode and photo transistor are used. The sensor is sensitive for

Most of the modern exposure meters are now equipped with the SBC sensor. Meters equipped with this kind of sensor can be recognized by the little ‘sbc’ shield on the meter.

The SPD cell or Silicon Photo Diode and the SBC Silicon Blue cell are both sensitive for infrared light and needs to be corrected with a filter. However the GPD or GAP Gallium Arsenide Photodiode is not sensitive for IR light.

The sharps silicon blue cell manufactured by photain controls is claimed to be the world’s first photo-electric diode possessing high sensitivity over the entire visible light spectrum. It is more reliable than the selenium or cadmium-sulphide photo-cells and has superior time response. No bias power is required, it has a lower noise level than the other two type and it is non-directional.


Type of meters

There are differences in type of meters actually in the way how to work with them. The oldest meters consist of 2 parts, a meter measuring a voltage (or current) and pointing to a value on a scale. and a kind of calculator disk to calculate the exposure by transferring the measured value to the calculator disk in some way. there is no electrical or mechanical connection between the 2 parts of the meter.

At the picture on the left, we can see that the meter consist of 2 parts, left part the calculator disk, part on the right the meter with the scale. Even in the current situation were the meter is taken apart, it is still functional and can be used for measuring the light values.

Another type of meter is the math needle meter. Here we have also a meter for measuring the light and a calculator disk for calculating the exposure vales. But instead of reading a value from the scale, there is another needle in the meter that can be placed directly above the light meter needle so the match in position. The movement of the match needle is done by for instance turning the calculator disk. As soon as the 2 needles match, we can read the exposure values in aperture and time from the calculator disk.

The Bix 3 is typical a match needle meter with a small needle, the actual meter needle and the wide needle, the match needle with a slot in this case. the slot must be placed directly above the meter needle by turning the big wheel. as soon as they match we can read the aperture / exposure time pare and select one depending if we want a high or low speed or a large or small aperture.


In order to get the correct exposure, you not only have to know the average reading , but you must also know the total range of brightness in the scene. Some Gossen meters operate on the zero metering principle (The null system). You simply align the needle on zero and the meter’s readout automatically shows you all applicable aperture / shutter speed combinations in 1/3 stop increments. No more reading a numerical value, setting it on the dial and then reading out the exposure values.

This ‘Null’ metering system is obviously quicker and easier. Interestingly, it is also unbeatable accurate. Indeed, it’s the method used with many on the world’s most precise laboratory instruments. Other meters may give you mid tone readings, but unless you know the full range of brightness in the scene you may lose critical highlight and shadow detail.

A +/-3 EV scale makes it easy to compare other areas with the key area on which you’ve ‘nulled’. It’s deal for scene brightness measurements and zone-system applications. And it works the same regardless of light level – no calculations.