PB20 Plenax

Posted 2-19-'04

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P B 2 0 (2 1/4 x 3 1/4)
"Pictures that Satisfy
or a New Roll Free"


The Agfa Ansco Plenax Camera has been so scientifically designed that exceptionally fine results are easily obtained without special photographic knowledge. Before making any exposures, read the instructions through carefully. Additional information may be obtained, if desired, by writing Agfa Ansco Corporation, Binghamton, New York, where a special department is maintained to give your inquiries prompt, courteous attention. For more complete details on camera operation and picture-making, the reader is referred to "Better Photography Made Easy," a particularly helpful, 6o-page booklet published by Agfa Ansco Corporation and sold by most photographic dealers at $.25 per copy.

The PB20 Plenax Camera takes 8 pictures 2 1/4X 31/4 inches or 16 pictures 1 5/8 x 2 1/4 inches on PB20 roll film. A wide variety of six different Agfa roll films is available in this size, every film guaranteed-"Pictures that Satisfy or a New Roll Free." 

The six types
Standard-moderate speed for average conditions.
Plenachrome - higher speed, orthochroinatic, for better outdoor pictures on bright days and dull days.
Super Plenachrome-extreme speed, high orthochromatic sensitivity and wide latitude for outdoor work.
Superpan Supreme-an improved, high speed panchromatic film for pictures day and night.
Superpan Press -phenomenal speed for greater subject range with any camera.
Finopan-fast, panchromatic, with extreme fine grain for big enlargements.

Explanation of numbers on opposite page.
1. Opening release button. Press in to open camera.
2. Platform. Pull down after releasing catch (r) until side-arm braces (3) lock.
3. Side-arm braces. See that braces lock and hold platform rigid.
4. Closing release button. Similar button is on opposite side of camera. With the camera held between the thumb and middle finger of the left hand, press the release buttons on both sides simultaneously. With the right hand, move platform upward until securely closed as indicated by clicking of latch.
5. Vertical footrest.
6. Focusing scale for various distances.
7. Diaphragm adjustment lever for controlling amount of light entering lens.
8. Shutter adjustment lever for varying shutter speeds.
9. Finger release for operating shutter. Press downward to make exposure.
10. Socket for addition of cable release for operating shutter. A cable release for this camera is available from the Agfa Ansco Corporation if desired.

11. Brilliant finder. Turn for horizontal pictures. Return to vertical position before closing camera. Swing mask marked "16" upward to obtain range of view for full sized pictures.
12. Bellows.
13. Winding knob for advancing film.
14. Tripod sockets. (Only one shown-other on front of platform). Remove screws with small coin to insert threaded screw on tripod head.
15. Release catch for opening back.
16. Direct view finder, for full-size or half size pictures.

To open the camera, hold it in the palm of the left hand and press the opening release button (11, Fig. r) with the left thumb. With the right hand, pull down the platform (2) until the side-arm braces are locked firmly in place.

Be certain, first, that the half-size mask on the brilliant finder (II) is down and that the finder is in a vertical position.
To close the camera, grasp it in the palm of the left hand and simultaneously press the two closing release buttons (4) with the thumb and middle finger. With the right hand then move the platform upward until it is securely closed as indicated by a clicking of the latch.
Repeat the operation of opening and closing the camera until you can do it easily and deftly. Never force the camera at any point. If any obstruction is encountered, stop at once and determine what is in the way.

The focusing scale will be found on the face of the lens mounting, next to the lens, and will be identified by the series of figures running from 5 to 100, as may be seen in Fig. 2. If the object to be photographed is 15 feet away, revolve the lens barrel until the figure 15 is opposite the indicating line above the word "Tripar" on the lens barrel. Distances from the lens to all objects from 5 to 10o feet should be estimated approximately and set off on the scale. For subjects at a distance of 10o feet or greater, the indicating line should be set at 10o.
To use the camera as a fixed-focus camera, set the lens barrel at 15 feet. When camera is used as a fixed-focus camera, set all indices on figures in red. Sharper pictures will result, however, if the lens is focused according to the index.

Fig. 2

Lens Mounting
The shutter is the mechanism which actually makes the exposure when taking a picture. Simply expressed, it does nothing more than uncover the lens for a very short period of time so that light from the object photographed may pass through the lens and project an image upon the film. However, it does this uncovering job with a very high degree of accuracy and with a suitable range in speed. Thus the portion of light admitted through the lens may be a very small one, such as that when the shutter is operated at one hundredth of a second, or a larger portion such as that when the shutter is operated at a twenty-fifth of a second.

Along the top of the lens mounting (Fig. z, page 7) is a row of figures and letters-T, B,
100, 5o and 25. T means Time, B means
Bulb, and 10o, 5o and 25 indicate 1/100, 1/50
and 1/25 second respectively.

To set the shutter for any of these speeds, move the pointer (8, Fig. r) to a position directly over the desired figure. In the shutter illustration, Fig. 2, the shutter is set for 1/25 second, the standard snapshot speed, and shown in red on the dial.
In addition to these figures on the front plate of the shutter, identically corresponding figures will be found on the top of the shutter as an aid in changing the settings without moving the camera from the waist-level position when focused on a subject.
The shutter is operated, or "tripped," by the finger release (g, Fig. r) or by a cable release if such has been added. Care must be taken when the release is pressed down in making an exposure not to jar or move the camera. If the camera is moved, a blurred picture will result. Holding the opened camera in the palm of the left hand, its back held firmly against the body for support, practice the shutter operation until you are certain exposures can be made without moving the camera.
When the shutter is set for 1/25, 1/50 or 1/100 second, a single pressure on the release
lever trips the shutter, opening and closing it.

When the shutter is set for B or Bulb (a term surviving from the days when the shutter was operated by a rubber bulb), it stays open as long as the lever remains depressed, and closes as soon as the pressure is released. Bulb is used for comparatively short time exposures, as for example, when light conditions do not permit the use of an instantaneous exposure. Since it is impossible to hold the camera perfectly still in the hand for any length of time, the instrument must be used on a tripod or other firm support when Bulb exposures are made. This is true of all expo
exposures longer than 1/25 second.

When set for T or Time, one downward pressure opens the shutter, following which a second pressure is necessary to close it. In other words, the lens remains open the full time, however long, between the two operations of the lever. T is used for interior work and longer exposures, such as may be counted with the second hand of a watch. Bulb or Time exposures should never be made of moving objects. The addition of a cable release is especially valuable for time exposures to prevent danger of moving the camera.

The diaphragm is an adjustable circular opening within the elements of the lens which controls the amount of light passing through the lens. When the diaphragm is adjusted so that the full aperture of the lens is utilized, it is said to be "wide open." When the diaphragm is adjusted to its smallest opening, it is said to be "stopped down."
This diaphragm is operated by means of the lever, (7, Fig. 1), also shown on Fig. 2 set under the numeral r6. This lever is connected with a pointer on the opposite side of the
shutter which moves along a similar row of figures on the flange at the top of the shutter. Thus, the diaphragm setting may also be read from above while holding the camera at waist level.
In order to view the operation of this diaphragm, set the shutter speed on Time and press down once on the finger release. Then, with the shutter open, move the diaphragm lever at the bottom of the shutter back and forth slowly, and you will be able to observe the change in the size of the opening as the lever moves.
The stops or settings indicated along the bottom of the shutter face plate and along the top flange are standard openings in the Focal or "f System," and are of known exposure value regardless of the size or make of camera. They are referred to as f:1111, f:16, f:22, f:32.

In figure 2 the stop indicator is set for opening f:16. With bright sunshine and a speed of 1/25 second, this is the opening for average pictures on Plenachrome Film. For twice as much exposure, which will be necessary on gray or cloudy days, the diaphragm may be opened to f:111. For half as much exposure, which will be required when taking pictures with intense sunshine, the speed may be increased to 1/5o second or the diaphragm opening reduced to f:22. It is evident, then, that the lower the number, the larger the opening, and of course, the larger openings let through more light, giving greater exposure within the same shutter speed.

In general, close-ups require a greater exposure than distant scenes; winter conditions necessitate longer exposures than bright summer days. Pictures taken with extremely in
tense light, such as sunlit beaches and brilliant snow scenes will require less exposure than normal.
Greater detail will result in your negatives when a smaller diaphragm opening is used. With the camera focused at 100 feet and the diaphragm set at f:11, everything from 17 feet to Infinity will be sharp and in focus. When the camera is focused at i00 feet and the diaphragm set at f:16, everything from 13 feet to Infinity will be in focus. Thus it is seen that the depth of focus, or the range of distance over which the picture is sharp and in focus has been increased by reducing the opening of the diaphragm.

The Plenax camera is equipped with a brilliant finder for locating the subject with the camera held at waist level.
The brilliant finder requires little explanation. When making 16 exposures to the roll it is used with the small mask marked r6 down. When full-size exposures are being
made, the mask must be raised upward and to the front in order to utilize the entire finder.
When making full-size exposures in the vertical position, read the finder as shown in Fig. 3, and when taking pictures in the horizontal position, swing the finder go degrees to the left and read it as shown in Fig. 4, disregarding the portions indicated in the cuts by white space.
Always remember to lower the mask and return the finder to the vertical position before closing the camera. Otherwise, they will become jammed and possibly thrown out of alignment.

Incidentally, it must be understood that in the exposure of half-size pictures, when the camera is in the vertical position, horizontal half-size pictures are taken, and vice versa. This point will be better understood when the
mask for reducing the film size is described at a later point.


The vertical footrest (5, Fig. r) is for taking Time or Bulb exposures when a tripod is not available. The footrest is easily extended by pulling it out at right angles to the platform, after which the camera may be set upon a table, ledge, or railing for support.
In order to use the tripod sockets (14, Fig. I) it is necessary to first remove the plug screws. This may be done with a small coin, after which the tripod is screwed securely into place. The screws should be replaced after removal of the tripod in order to protect the interior of the camera against dust or other foreign matter which might prove injurious to the shutter mechanism.
The vertical tripod socket is located in the center of the camera platform; the horizontal socket is on the camera side plate below the film winding knob.
The vertical footrest or a tripod should always be used for exposures longer than 1/25 second rather than attempting to hold the camera in the hands.

To load the camera, it is first necessary to open the back which is held by a catch (r5, Fig. I) at the top under the handle.
In order to release this catch, hold the camera in the left hand, platform side in and handle to the top. Then lay the fingers of the right hand across the camera handle and exert an upward pressure upon the under front edge of the long metal catch (Fig. 5). When this catch has been released, continue with a backward pressure to swing the hinged camera back downward.
Repeat the operations of opening and closing the back until you can operate the catch easily and deftly.


Before loading the camera it is essential for you to determine the size of pictures desired for the particular roll being loaded. You have the choice with the same roll of film, between loading the camera for 8 full-size pictures or for r6 half-size pictures.
Upon opening the camera back for the first time you will notice a black rectangular frame (I, Fig. 6) between the film rollers (2, Fig. 6). This frame or mask determines the size of the exposure made on the film. When it is in place, the picture size is reduced by half, and i6 exposures to the roll are obtained. When the frame is lifted out and entirely removed from the camera, 8 full-size exposures are obtained from one roll.

Due to the fact that the film is stretched on top of this mask, decision as to the picture size should be made before the camera is loaded, for it is necessary to continue this size picture until after the roll has been fully exposed.
Upon the removal of the mask for full-size pictures, care should be taken to place the metal frame where it will not become lost or bent. However, a new mask can always be bought from your dealer.

With the back open you are now ready to load the camera with film. Note that the fresh roll goes into the lower chamber at the opposite end of the camera from the winding knob. In the chamber at the knob end, you will find an empty metal spool. It is onto this spool that the film is wound as used, so that when all exposures are taken it is this top spool which is removed from the camera for finishing.
It should be remarked at this point that the small, compact size of your Plenax Camera requires film wound on the new small metal spool, designated by the Agfa Ansco Corporation as PB20. Be sure to ask for the thin metal spool, as this camera will not accommodate film wound on the ordinary larger wooden film spool.


To load the film into the camera, first swing up the spool carrier for the lower or empty chamber until it is at right angles to the camera. Holding the two ends of this carrier slightly apart (being careful not to bend them permanently out of position), drop the fresh spool into place, taking care that it is inserted right end around. In other words, be certain that the pointed end of the paper will come from the top and not the bottom of the roll, and that only the red or green side of the paper will show, the black side being toward the lens.

After being certain that the two pins set in the carrier ends are engaged in the spool end holes, swing the carrier and film down into place in the chamber. Break the sticker which seals the roll, remove the Agfa Film guarantee slip, and carry the end of the paper across the back of the camera, and across the black metal mask if it is being used. Permit the paper to pass over the two metal rollers (never attempt to thread the film under these rollers) and thread the pointed end into the slot in the empty spool as shown in Fig. 7.

Be very certain that the paper is centered on the upper spool in order that it will wind evenly. Now give the winding knob a few turns, sufficient to bind the paper and assure its firm grasp by the upper spool. Close the back of the camera by swinging it upward into place until a click indicates that it is locked securely. Never open the back of the camera from this point until the roll has been completely exposed.
Swing open the No. I Peephole cover (Fig. 8), and continue turning the winding knob slowly until the figure I appears in this lower peephole. An indicating hand and row of dots will be seen shortly before this first figure appears in place.
The camera is now ready for the first picture.
When using Panchromatic film, which is sensitive to red light, be sure to keep the red windows covered at all times except when winding the film.

If eight full-size exposures are being taken and the masking frame has been entirely removed from the camera, only the No. I or lower peephole is used throughout. In which case, immediately after taking the first picture, wind again until figure 2 appears in the lower peephole, and so on until the roll has been completely exposed, after which continue to turn the knob until the red or green paper is completely wound off onto the spool at the knob end of the camera.
Where sixteen half-size exposures are desired and the masking frame has been left in the camera, both the No. r and No. 2 peepholes are used. The first exposure is made with the figure I at the lower window. After a picture has been made with the film in this position, the winding knob is then turned very slowly (only about one full turn of the knob necessary) until the figure I appears at the upper or No. 2 peephole. For the third exposure the figure 2 is at the lower window, for the fourth it is moved to the upper, and so on until all sixteen exposures have been made. In other words, one exposure is made with each of the eight numbers at both windows.

When the film has been completely wound onto the knob spool, open and swing down the hack of the camera. Pull out the winding knob until the upper spool carrier is free to be moved upward from the chamber.
Fold under the pointed end of the red or green paper, and seal the spool with the sticker which will be found at the loose end. This is to prevent unrolling and fogging of the film after it has been removed from the spool carrier.
With the fingers, separate the ends of the spool carrier slightly and remove the exposed roll from the camera. It is now ready to be developed and printed. Transfer the empty spool to the upper chamber, remembering to push the winding knob back into place. The camera is now ready for the insertion of a fresh roll of film in the manner already described.

Your Plenax Camera may be loaded or unloaded in daylight, but not in direct sunlight.
Before , loading the camera, make certain that the shutter is closed.
In starting the red or green paper at the time of loading a fresh roll, always see that it is even, fitting the spool neatly. Otherwise, it is likely to climb up one end of the spool, causing the protective paper to tear and possibly fogging the film.
Also, always make it a practice to wind to the next number immediately after taking a picture. In this way double exposures are prevented.
Always hold the camera level and perfectly still when making the exposure.
Keep the lens of your Plenax Camera clean. A dirty lens or rain or mist on the front lens will cause fogged or cloudy pictures. To clean the lens, use a soft linen or cotton cloth.
Do not let the sun shine directly on the lens when taking a picture. If photographing towards the source of light, hold your hand or hat above the lens as a shade, but sufficiently high to prevent its being included in the picture.
Select your background carefully. A good subject can be spoiled by such backgrounds as telephone poles, clapboard houses, etc. Keep your backgrounds simple. A background of foliage is usually unobtrusive and pleasing.
Portrait attachments, color filters, and cable releases which are available for Plenax cameras greatly increase their versatility.