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HOW TO BUILD
A PANORAMIC CAMERA

Giorgio Carboni, November 2002
Translation edited by Charles and Mary Perry

 


 

Panoramic camera, front view

Panoramic camera, back view

TABLE OF CONTENTS

PREFACE
INTRODUCTION
TYPES OF PANORAMIC CAMERA
FABRICATION
OPTICAL AND MECHANICAL SCHEME
MATERIALS
THE OBJECTIVE
THE ROTATING DRUM
THE CAMERA BODY
THE FRONT WINDOW
THE BACK DOOR
FILM WINDING
DEVICE FOR THE ROTATION OF THE OBJECTIVE
VIEWFINDER
BUBBLE LEVELS
STRAP
FITTINGS
ADJUSTMENTS
CENTERING THE OBJECTIVE
MEASURING THE SPEED OF ROTATION
USING THE CAMERA
EXPOSURE
TO SHOOT
CHARACTERISTICS OF THE SHOTS
THE PERSPECTIVE
TO SHOOT IN CYLINDRICAL PERSPECTIVE
OBSERVING THE PICTURES
IMPROVEMENTS
MAINTENANCE
INTERNET RESOURCES
CONCLUSION


PREFACE

Some years back, we published an article showing some panoramic pictures taken with a handmade panoramic camera. We also said that in time we would publish an article on the construction of this camera, but we were putting it off for several reasons, the main one being that building this camera is a demanding task and we wanted to publish some simpler articles first. Nevertheless, many readers continued to write to us asking when this article would be published, pressing us for its publication, reproaching us, even if amiably, because we hadn't done it yet. Well we could delay no longer so here it is. If the fabrication of this camera is too demanding, please forgive us and make note that we have also supplied some simpler methods for making panoramic pictures.

Perhaps you've experienced this: you've shot some pictures of magnificent landscapes but when you see your prints they are unable to return even a faint resemblance of its beauty, its spaces, or its colors and lights. How many times have you seen a mountain turned into a molehill, an impressive building into a modest house, a street into an alley? You wish you could stretch its borders to see a wider space. In this article, we will describe how to build a panoramic camera with which finally you will be able to obtain in a print what your eye has seen, in particular the right proportions of objects and the charm of a wide-angle view. While beautiful things have a price -- the fabrication of this machine is not within everyone's ability and the cost of large format prints is quite high -- be assured that it is worth it because of the breathtaking pictures which can be obtained!


INTRODUCTION

How was this camera born? As we said in the preface, when viewing our pictures we felt they needed to be wider. We didn't know if it was technically possible but the wish became stronger and stronger and we started to take "panoramic pictures" composed of several photographs placed side-by-side. We simply shot a series of pictures, "panning" across our view, making sure that the individual shots overlapped each other. Then we glued the prints, matching the overlaps, to obtain a comprehensive view. The collage was far more agreeable than each picture alone. From the collage emerged a sense of space which could not be supplied by a single picture. It was confirmed that by broadening the borders of photographs it was possible to gain much in their charm. However, the system of collage was not satisfactory, first of all because the interruption between one picture and the next broke the enchantment. Moreover, the prints could not always be well aligned or matched to each other in focus and exposure. Finally, buildings represented by multiple shots had their orthogonal lines broken. To solve these problems, we thought to build a camera with a rotating objective and the film arranged in a cylindrical way. We hadn't the faintest idea if this type of camera would work nor did we know that this basic design had been in use since Friedrich von Martins' "Megaskop" camera in 1844. It becomes increasingly difficult to invent something new so we contented ourselves with reinventing an inexpensive camera of exceptional performance.

When we started to design and build this camera, those who saw the prototype under construction shook their heads as if to say it would never work. Nonetheless, we went ahead thinking that at least this was an interesting optical experiment. After several months we completed the camera and made some tests, the results of which were far beyond our expectations. When we showed the first pictures to our friends and colleagues who before were so skeptical, they were stupefied and started to revise their theories and explain to me how it was possible that this camera was working..... and it worked well indeed!


TYPES OF PANORAMIC CAMERA

There are three main types of panoramic camera: widefield -- a wide angle objective and wide film; swing lens -- a camera with a rotating objective; rotation camera -- a camera with a rotating body and synchronized moving film.

Wide angle camera

Swing lens camera

Rotation camera

Widefield Camera.
The widefield camera is the simplest. The wide-angle lens does just what it says, which is cover a very wide angle. The film plane is flat and wide. The angle of view can be calculated on the basis of the focal length of the objective lens and the width of the film plane (figure 3). For a given image width, the shorter the focal length, the wider the field of view will be. The main disadvantage of wide angle objectives is that distant objects become smaller and squares are lengthened into rectangles. Mountains become small and plazas vast. This happens because the distance between the objective and the border of the film is greater than that between the objective and the center of the film. Consequently, objects in the center of the picture are shown smaller than those at the edges.

Wide angle lenses can be divided into normal wide angle and fisheye. Normal wide angle lenses have the advantage of keeping rectilinear and orthogonal lines true. The fisheye lenses can cover more than 180 degrees but they work in spherical perspective, bending the orthogonal lines and distorting things in ways which are not always appreciated. If the camera is pointed straight up, it will cover 360 degrees.

Swing Lens Camera.
In these cameras, the objective lens rotates. There is a narrow vertical slit between the lens and film, which rotates with the lens, allowing the image to be progressively exposed as the lens rotates. The film plane is curved so that the long strip of film being exposed is always the same distance from the lens, this distance being the focal length of the objective lens (figure 4). Usually, these cameras cover a field of 120 to 150 degrees horizontally and 30 to 50 degrees vertically. The camera we are preparing to build is a swing lens camera.

Rotation Camera.
In this third type of panoramic camera, the lens is fixed in relation to the camera body but the entire camera rotates. The film moves like a conveyor belt at a speed synchronized with the speed of the moving image, so as to assure congruency between the image and the film (figure 5). There is a very  narrow vertical slit behind the objective which allows the changing image to be "laid onto" the moving film a little bit at a time. These cameras are able to take shots of 360 degrees or more -- they can keep rotating until they run out of film. Usually these cameras use film type 135 (35 mm).


OTHER WAYS TO TAKE PANORAMIC PICTURES

A Sequence of Pictures.
A widely used system to take panoramic pictures is to take a sequence of shots side-by-side. To do this, you have to rotate the camera for each shot so that each frame overlaps the preceding frame. A tripod should be used. A goniometer or points of reference on the rotating head of the tripod itself helps, but you can also just note what is on the edge of the first picture and include it on the opposite edge of the next frame to ensure the frames overlap. A bubble level should be used as the camera must be kept level. Often these levels are built into tripod heads. You can physically cut and paste your photos together or you can scan them into a computer and join them together into a seamless panorama using a computer program designed for this purpose. These programs work well making it impossible to detect where the images are joined.

The Pinoramic Camera.
A fascinating system for making panoramic pictures is that of the Pinoramic Camera described by Kurt Mottweiler. In this camera, which covers 120 degrees of horizontal field, a pin hole takes the place of the objective and the film is stationary in a cylindrical arrangement. The "objective" does not rotate, but the author states there are no important differences in exposure between the center and the borders of the photogram. It is a nice camera, easy to use and easier to make that a swing lens camera but like all pinhole cameras is limited in the sharpness of the image. To a certain extent, the sharpness of the image can be increased by making the diameter of the pinhole smaller. If you glue a small lens of the proper focal length over the pin hole, the central zone of sharpness will increase, but the sharpness will decrease at the borders. You can find a link to a picture of this camera in: "Internet Resources".


FABRICATION

OPTICAL AND MECHANICAL SCHEME

Swing lens panoramic camera

Clearly, there are lots of ways to build this type of camera. You can use metal or wood, 135 or 120 format film, etc.. We will describe the camera we experimented with and built. As we said before, from an optical point of view this instrument is characterized by having an objective lens that rotates at a constant speed during the exposure, and by having the film arranged in a cylindrical way.

As shown in figure 6, the objective is put into a rotating drum, which in our case is made up of a brass tube 80 mm in diameter. There is a slot in the front of the drum and one in the back allowing light to pass through.

The body of the camera consists of a top and bottom plate separated by four little columns (figure 7). These two plates hold the guides on which the film will slide. The front and ends of the body are made of two bent brass sheets and screwed on the plates. In figure 7, we have shown only the main parts of the camera body, the other parts will be described and shown later on.

Camera body



Between the front sheets and the rotating drum, there are two plates. They are covered by black velvet which skims the drum and prevents light from penetrating (figure 6). A front door of curved plate protects the drum and has to be opened before exposure (figure 1). In the back, a door is mounted on the camera body by a hinge and completes the protection of the camera (figure 17). On the top, a special space contains the device for the rotation of the drum (figure 24). The lock for the back door, the rotating columns to support the film, the knobs to wind the film, the hole to observe the advancing of the film, the upper and lower bubble levels, the transparent lid which allows observation of the rotation device, the viewfinder to establish the borders of the shot, the threaded hole for the tripod, the strap and its fastenings, the battery holder and the operation button complete the instrument. Perhaps the most critical part of this camera is the device for the rotation of the objective. It is moved by a small electric motor and it is made up of a series of wheels which work by friction. Later on we will see all these parts in detail.


MATERIALS

To build this camera we have mainly used:
-sheets of brass 0.2, 0.5,1,10 mm thick
-a tube of brass 80 mm in diameter with 1 mm wall
-a brass rod 4 mm in diameter from which we have made several little columns
-a brass rod 15 mm in diameter
-a rod of black PVC plastic 10 mm in diameter to support the film
-two hardened steel bars to support the film
-a plate of transparent Plexiglas 3 mm thick
-some commercial components: screws, pins, a metal hinge, springs, spheres, ball bearings, rubber belts for tape recorder or cassette player, an electric motor, cables, plugs and two bubble levels.
-some components obtained from photographic cameras: the objective has been obtained from a Rolleiflex expressly bought for the purpose. From another 6 X 6 camera, we have obtained the locking system, the winding knobs for the film, the anti-unrolling device for the film, and a folding viewfinder.


THE OBJECTIVE

For this camera, use a commercial objective. You can buy one or remove one from another camera. All objectives have a certain covering ability, that is, the image they produce has enough uniform luminosity for some distance from the optical axis. Beyond this distance you cannot use the image because it is too faint. The shape of the covering field of the objectives is then circular. This also means that the objectives designed to work for 24 X 36 mm format cannot be used for larger formats because they will not cover the film. So, you must first decide the format of the film you want to use and then choose among the objectives which are used for that format. The more widespread formats are the "135", which usually measures 24 X 36 mm, and the "120", which usually measures 4.5 X 6, 6 X 6, and 6 X 9 cm. 135 film has a useful height of 24 mm, while 120 has a useful height of 58 mm. The field of view being equal, clearly the larger film will allow you to obtain images much more detailed than the smaller one.

For these types of panoramic shots, the vertical field should cover about 40 degrees. With 135 film, an objective of 30 mm focal length covers a vertical field of 44 degrees. With 120 film, an objective of 75 mm covers a vertical field of about 42 degrees. In all cases, the radius of the curved cylinder of film has to be equal to the focal length of the objective.

The objective we have used is a Tessar Zeiss, 75 mm focal length removed from a Rolleiflex. This is a high-quality objective; it has a high micro-contrast and it produces sharp images. It has a comparatively long focal length and with it we obtain negatives measuring 58 X 160 mm. This large negative size covers a field of 120 degrees horizontally and 42 degrees vertically. The vertical angle is much less than the horizontal one, but you will see that even it is a wide angle. In fact, 42 degrees is the same angle of coverage as the longer side of a 135 format image using a 50 mm lens.

Objective and its adjustable support

Lateral adjusting screw

Figure 8 - The objective is mounted on a plate, the position of which is adjustable by means of three screws. The two little columns are fixed on the bottom and top (top-not shown) of the drum (drum not shown).

Figure 9 - Detail of the screw which sets the horizontal position of the objective.

In this type of camera, the vertical field is small in relation to the horizontal one. This is justified because subjects for panoramic shots, especially if they are distant, are usually arranged along the horizon. But what if your shot is a cityscape with tall buildings where a greater vertical field would be useful? To face this problem, this camera's objective has been mounted with an upward "shift", allowing the camera to shoot a wider field in this direction (figure 10). This shift is also advantageous when shooting a subject from a high position, because by turning the camera upside-down, you will be able to take a wider angle downward. The shift of the objective is 11 mm and allows the camera to obtain an angle of 28 degrees above the line of the horizon and 13 degrees 30 minutes below the horizon for a total of 41 degrees 30 minutes. You must be sure that the objective you want to use has enough area of coverage to avoid vignetting. If the objective won't shift that much without vignetting then you must reduce or do away with shift, or obtain another objective. If you do not understand this business of "shifting" the lens and "vignetting" then I recommend you do some research on those subjects in relation to view cameras.

Decentering the obiective


THE ROTATING DRUM

The rotating drum holds and protects the objective (figure 11). Its main function is to allow the rotation of the objective while preventing parasitic light from entering the camera. The rotating drum consists of a brass tube, 80 mm in diameter and 1 mm thick. It has two slots, 5 mm wide, through which the light destined to expose the film passes. The drum is closed on the top and bottom by metal disks. Each disk has a pivot which will be inserted in a ball bearing on the camera body.

Rotating drum

Figure 11 - Rotating drum. The upper disk has been removed to show the objective and its centering device.

 

To be sure that the pivots and disks are centered exactly on the drum, I suggest you mount it with the disks on a lathe. With this machine tool, remove some metal until the drum rotates true. In order to recover the same position when you disassemble and reassemble the disks, make a reference line on the border of the disks and on the drum.

The objective has to be positioned so that its rear optical node is exactly on the rotating axis of the drum. If this does not happen, the image will move on the film during exposure, causing a loss of sharpness. The objective is mounted on a metal plate which is fixed on two columns by means of three screws (figure 8). By adjusting these screws, you can set the position of the objective. A lateral screw (figure 9) allows you to also set the position of the objective in the right-left sense. Later on we will see how to do these adjustments.


THE CAMERA BODY

The main parts of the body of the camera (figures 7,12 and 13) are the upper and lower plates (separated by four brass columns), the flange, the guides for the film, the anterior and lateral walls, the back door, and the front window.

 

Camera body (section)

 

 

Camera body (back view)

 

The upper plate (figure 14) consists of different parts soldered with tin. The main one holds the guide for the film. The bottom plate is like the upper one, except it has a hole to insert the drum (figures 12 and 13). This hole is closed by means of a flange (figure 12).

 

Upper plate


The flange has a ball bearing upon which the drum rotates. Another ball bearing is on the upper plate. On the flange is soldered a thin sheet to prevent light from entering the camera. A 1/4" thread serves to mount the camera on a tripod (figure 12).

 

Bent sheets

The front part of the camera is closed by two sheets which follow the body's profile (figure 7). Four sheets bent at 90 degrees (which are not shown in figure 7) hold the front sheets of the camera to the upper and bottom plates (figure 15). These bent sheets also prevent light entering. They are soldered on each front sheet. The front sheets are assembled to the camera by means of screws (figure 15) and they also strengthen the structure of the camera.

To avoid parasitic light from entering the camera, there are two light baffles between the camera body and the drum (figures 6 and 33). They are shaped like a bent tile and are made of the same type tube used to make the drum. Each baffle is mounted to a column. They are covered by black velvet and are "hinged" at the column so as to be free to swing back and forth slightly on the column and lightly skim the drum without braking it.


THE FRONT WINDOW

 

 Front window

The front window protects the drum and shields the camera from external light (figures 1,16,24,32). It is made of a bent front sheet and two half-moon shaped sheets which are placed on the top and on the bottom. These three sheets are screwed on to two little brass columns, then soldered to form one piece. The front window is fastened to the camera by means of three screws. A door is hinged on one side and it hooks on the other. A little stroke made with a finger is enough to unhook it and uncover the drum. To avoid this door accidentally opening, it is sufficient to insert under it a thin piece of card. You can use the top of a film box to do this.


THE BACK DOOR

Back door

Hole to check the film advance

Figure 17 - Back door of the camera.

Figure 18 - Hole to check the film advance.

 

Three sheets (upper, lower and back) and four brass columns make up the back door (figure 17). These parts have been assembled with screws and then soldered with tin. Soldering makes the door a uniform body, closes all fissures and gives it rigidity. On the back door, a hole to read the number of the picture has been made (figure 18). It has been protected with a dark red filter and it can be opened or closed by means of a slider. On the right side, the back door is joined to the camera body by a metal hinge (figure 19). On the left side, you have to place a locking device (figure 20). This device can be obtained from another camera.

 

Hinge

Lock

Figure 19 - Camera body seen from the hinge side.

Figure 20 - Camera body seen from the locking side.


FILM WINDING

The new film roll has to be inserted between a lower and an upper pin (figure 21). The upper one should be movable upward enough to allow the roll to be inserted, then it is lowered again. The same is true for the take-up spool on which you will wind the film when you make shots (figure 22).

Looking at the camera from the back and with the door opened, the film is inserted on the left side. It has to pass under the rotating PVC column on the left side, then it has to pass under the two little brass columns, then under the rotating PVC column on the right side. Finally it has to be hooked to the empty spool (figure 23). By rotating the knob on the right, the film advances on the guides which keep it in a cylindrical arrangement and at the focal length distance from the objective, which in this case is 75 mm.

 

Film housing

Film housing

Figure 21 - Housing for the film spool. Notice the pins on which the spool has to be inserted, and the PVC column. The diameter of this column is reduced in the center. A springy metal blade presses the film on the thinner position of the column to give the film the right arrangement and to prevent it going out of its guides. The little lateral steel blade aids in the alignment of the spool on the pins. Inside, you can see one of the oscillating light baffles covered by velvet and the column on which it pivots. In the bottom, you can see the darkened back of the lower bubble level.

 

Figure 22 - Housing for the take-up spool. Notice the PVC column, and the sheet which leans on it and which determines the border of the image. The lateral steel blade makes it easier to extract the exposed film. Finally, notice in the bottom, the bent sheet which lies in the corner between the bottom plate and the front sheet.

Two curved sheets 0.2 mm thick, made of brass, determine the horizontal dimension of the photo (figures 6, 21, 22). They are placed to obtain an image 122 degrees wide, which corresponds to a length of 160 mm on the film. The first time we tested the camera, the film had a tendency to go out of the guides and to arrange itself as the cord of an arc between the two PVC columns, completely ruining the shots. To avoid this major problem, we reduced the diameter of the first PVC column in its center zone and we added another spring steel blade to give the film the right shape at the beginning (figure 21).

The knob which winds the film should be able to move only in the forward direction and it has to be prevented from turning backwards. To this purpose, a one-way locking device such as a freewheel or similar system is useful. We have used a simple device obtained from a recycled camera. It consists of a spring wrapped on the winding pivot. By rotating in one direction, the spring tends to widen and allows the pivot to move. By rotating in the other direction, the spring grips and prevents the pivot from moving.

 

Camera with film

Figure 23 - Camera opened to show the film. The feeding direction is from left to right. The two little central columns do not have any role in the arrangement of the film and serve only to join the upper and the lower plates and to keep them at distance.

The light sensitive surface of 120 film is 61.7 mm wide and 810 mm long. It is shielded by a strip of paper which is blackened on the film side. This shielding strip is 63 mm high. On the rear side of the shielding strip, the numbers to control the film feeding are printed. The numbers on the bottom, suited for 45 mm long pictures, are those to be used in our case. These numbers are 48 mm apart. As our pictures are 160 mm long, when you feed the film you will have to skip some numbers. In our case, we use these numbers: 3, 7,11, 15, for a total of four pictures per roll. Between one picture and the next, remains 32 mm of unused film and, when the film will be cut into single negatives, you will have borders useful for their handling. The exposed and processed film should be stored in suitable holders.


DEVICE FOR THE ROTATION OF THE OBJECTIVE


A device rotates the drum and hence the objective of the camera for about a half of a turn. This device is housed in a special space located on top of the camera which keeps the same outline of the camera (figure 24). This space also contains a bubble level to check the attitude of the camera; it is closed by a transparent lid made of Plexiglas (figure 25). Two knobs to maneuver the film protrude through this lid and a viewfinder is placed on top. Under the lid, two cables to power the electric motor and two microswitches to stop the turn of the drum are fixed.

View of the upper space Transparent lid

Figure 24 - Housing for the rotating device of the drum. It is closed by a transparent lid. Besides the rotating device, there are the cables and the bubble level. On the lid, the folded viewfinder and the maneuvering knobs for the film are visible.

Figure 25 - Plexiglas lid seen from the bottom side. Notice the microswitches, the holes for the electric motor and those for the knobs, the circular groove for the pin on the main wheel and the half-opened viewfinder.

 

Several times during the fabrication of this camera, we have had to remake many parts because of drawing errors, fabrication errors, unexpected situations, etc. No other part caused us as many problems as the rotating device did. We tested different rotating systems, until we found effective a device based on friction wheels and moved by an electric motor. This system works quite well and it is a valid for this camera. However, a good electronics technician could design a more versatile system, capable of a wider range of speeds and which does not suffer, at least until a certain point, from battery power loss.

Our device uses a 9V DC electric motor. With this voltage, this motor turns at about 12,000 rpm. The motor is mounted on a pivoting pin (figure 27, pin 1) and it is kept slightly pressed against the intermediate wheel by means of a spring (figure 27,spring 1). The intermediate wheel is also mounted on a pivoting support (figure 27, pin 2), so that it can be slightly pressed against the main wheel by means of another spring (figure 27, spring 2). Both the intermediate and main wheels are made of Plexiglas and a rubber belt is mounted on their external diameter. The axle of the motor and the hub of the intermediate wheel are bare metal.

 

Device for the rotation of the objective

Device for the rotation of the objective

 

The axle of the electric motor has a diameter of 2 mm. In order to vary the rotation speed of the objective, we mounted a wheel with two diameters on this axle. In this way, we have the following three diameters at our disposal: 2,4, and 8 mm. The electric motor can be placed in three vertical positions to engage one of the three diameters on the intermediate wheel (figure 26). This allows us to choose among three different speeds of rotation of the objective to vary the exposure of the film. The intermediate wheel has diameters of two and 42 mm, and the main wheel has a diameter of 72 mm (figures 26, 27, 28, and 29).

 

Main wheel

Intermediate wheel

Figure 28 - Device for the rotation of the objective. Notice the main wheel, the intermediate wheel and the electric engine. Behind, you can see the bubble level mounted on adjustable screws. The front window has been removed to better show the main wheel and the drum.

Figure 29 - Intermediate wheel. Notice on the left the spring which pulls the intermediate wheel against the main one (removed). You can perceive the axle of the motor against the intermediate wheel.

 

Power supply

Another method to increase the range of the rotation speeds of the objective is to change the supply voltage of the motor. The power supply of our rotating device is made up of a box holding 6, 1.5V batteries. Outside this box you can see a black connector (figure 30). Its contacts are arranged to connect the batteries in series and to obtain 9V. By replacing it with another with the contacts arranged in parallel, we obtain 1.5V. In this way, we get another series of three rotating speeds.

Also on the power supply there is a button to deliver the voltage to the electric motor. When you shoot the picture, you have to keep this button pressed until the end of the rotation of the drum. Then there is a switch which reverses the polarity of the voltage on the electric motor and reverses the spinning direction of the motor and hence of the drum. The power supply has a cable ending with a plug which has to be connected to the camera.

 

 

Figure 30 - Power supply of the camera. It contains six 1.5 V batteries. Observe the cable and the plug to connect the supply to the camera, the switch to reverse the polarity of the voltage, the connector to change from 9 V to 1.5 V, and the red button to deliver the voltage.

 

The mechanism for the rotation of the objective is placed on the body of the camera, inside a space which has the same outline of the camera and which is closed by a Plexiglas sheet so the operator is able to check the correct functioning of the system. A female connector is placed on the border of this space and the plug from the power supply engages it. Inside the upper space, some cables bring the current to two microswitches which cut the current when they are pressed. To this scope, the main wheel, which is mounted on the drum axle, has a pin screwed on it. During the shot, this wheel spins until its lateral pin hits a microswitch and the current is cut. In this way, these microswitches work also as mechanical stops. At this point, the operator has to wind the film to be ready for a new shot. Now, by moving the switch to the other position and by pressing on the red button, the electric motor will be powered with reversed polarity and the drum will move in the opposite direction until the lateral pin of the main wheel kicks the other microswitch. In order to be allowed to remove the Plexiglas plate, the cables are interrupted by two plugs. One of them is before the microswitches and the other is near the electric motor (figure 25).

The data collected on the following table refers to our power supply with new batteries.

CHARACTERISTICS OF THE ROTATING SYSTEM OF THE OBJECTIVE

moving wheels / moved wheels

reduction ratio

revolutions per minute
(9V)

exposure speed
(9V)

revolutions per minute
(1,5V)

exposure speed
(1,5V)

8 x 2 / 42 x 72

1 / 189

60

1/60

12

1/12

4 x 2 / 42 x 72

1 / 378

30

1/30

6 1/6

2 x 2 / 42 x 72

1 / 746

16

1/16

3,3 1/3,3


VIEWFINDER

The viewfinder is a gun sight type. It consists of a base plate on the rear of which there is a sheet with a little central hole and in the front of which there is a little Plexiglas plate (figure 31). Some lines are engraved on this plate: a vertical line which indicates the right and left borders of the picture (1), a horizontal line which indicates the upper border of the picture (2), a second horizontal line which indicates the horizon (3). The bottom border of the picture is roughly indicated by the base of the transparent plate. To see the left and right borders of the picture, it is necessary to rotate the viewfinder around the screw (5) which links it to the Plexiglas lid. The heads of two other screws limit the movement of the viewfinder toward the right (6) and toward the left (7). The two vertical ends of the viewfinder can be folded and, by pressing a button (8), they can be re-opened by means of springs.

Viewfinder

Figure 31 - The viewfinder.


BUBBLE LEVELS

As we have said, the bubble level for the control of the attitude of the camera is placed in the upper space. The bubble is glued on a support with three adjustable screws (figure 28). Another bubble level is placed under the bottom plate and is used when the camera is used upside down (figure 32). These bubble levels have a spherical surface; usually they are used for scales and they can be bought in hardware stores.


STRAP

The camera is supplied with a leather strap which facilitates its handling. This strap is fixed on to lateral slots (figure 32). Its fixing method is the same as that used on binoculars.


FITTINGS

During the shots, you must mount this camera on a tripod. It has to be strong enough to prevent vibration from the rotation of the drum. An important fitting is a metal strap to mount the camera upside down on the tripod (figure 32).

 

Overturned camera

Figure 32 - Metal strap to mount the camera overturned on the tripod. The yellow arrow shows the position of the bottom bubble level.

When you are not using the camera, place it in a bag. Keep with it a screwdriver, a toothpick or some such tool to maneuver the diaphragm, a little ruler to measure the diameter of the diaphragm (some credit card sized calendars have a ruler printed on one of the edges), a notebook and a pencil for location and exposure data. A little hand truck with two wheels, like those used to carry suitcases, can be useful. You can place the bag and the tripod on it.


ADJUSTMENTS

CENTERING THE OBJECTIVE

If the objective is not suitably centered then when it rotates the image will shift on the film causing a loss of sharpness. To prevent this, it is necessary that the posterior optical node of the objective be on the axis of rotation of the drum. In our article: "From Lenses to Optical Instruments" we explain what a node is. It is not necessary to know its exact position in order to place it on the axis of rotation of the drum. Read on and we will describe how to adjust the position of the objective.

During this adjustment, it is necessary for the camera to be completed. In particular, the objective must be mounted on the drum and the drum inserted in the camera. For greater convenience, remove the back door and the front window. You can see from figures 8, 11, 12, and 33, the objective is mounted on a little plate and you can adjust the position of the objective by means of three screws. To access these screws, you must have made three holes for the passage of a screwdriver or Allen wrench in the drum wall, according to the type of screw you are using.

 

Mounting the objective

 

To be able to adjust the exact position of the objective, it is necessary to observe the image it produces with a magnification of about 50X. Figure 34 shows how you can perform this control by using a student microscope and a slide. With suitable shims, align the objective of the microscope at the same height as the objective center of the camera. Focus the objective of the camera for Infinity. Remove the stage of the microscope and fasten the camera on it. Shorten the microscope slide so that it fits on the guides of the film. Keep the slide in contact with the guides by means of two rubber bands. What is the use of the slide? The dust which is present on it, or some thin lines drawn on the slide, can be used as reference marks to assess the movements of the image.

 

Adjustment of the objective with a microscope

Figure 34 - How to use a microscope to adjust the position of the objective of the camera. Notice the slide mounted on the guides of the film with two rubber bands.

 

Vertical Slope of the Objective.
With reference to figures 34 and 35, observe a small, distant object to use as a reference. In the following figures, we have represented this object as a point. Rotate the drum by 180 degrees. If you see the image of this object go up or down on the slide, rotate the screws on the support of the objective in order to modify its slope. More specifically, you have to adjust the two screws which are on the same column (see figure 8) by rotating them in opposite directions and the same number of turns. Repeat the operation until you have eliminated the vertical movement of the image.

Right-Left Coaxiality of the Objective.
With reference to the figures 34 and 36, rotate the drum by 180. If you see the image of the object taken as reference to shift horizontally on the slide, adjust the lateral screw (figure 9) until to annul this shift.

Adjustment of the objective slope

Adjustment of the objective coaxiality

Forwards-Backwards Coaxiality of the Objective.
With reference to figures 34 and 37, rotate the drum back and forth by some degrees (until the image disappears from the slide). If during this rotation you see the image shift horizontally on the slide, move the three screws of the support in order to move the objective forward. If the shift of the image increases, make the adjustment in the opposite direction until the image keeps steady. In order to keep the objective parallel to the film you have to rotate the three screws of the support in the same amount and direction. To this scope, it can be better to use allen screws which allow you to better judge the degree of their rotations than with a screwdriver.

Adjustment of the coaxiality of the objective

Adjustments of the Focal Length of the Objective.
With reference to figure 34, check that the slide adheres properly to the guides. Fully open the diaphragm of the objective of the camera. With the microscope, focus a particle of dust which is on that part of the slide surface which is in contact with the generatrix of the guides. Let us call this position of the microscope focus knob: position 1. Now, with the camera, look at an object placed at a distance of about 70 meters and focus on it with the microscope. Let us call this position of the focus knob: position 2. Between position 1 and position 2 there will probably be a difference and this means that the image focuses in front of or behind the film. In both cases, this will cause a reduction of the sharpness of the image. To eliminate it, you have to rotate the first lens of the objective of the camera, performing the operation known as "to focus". However, this operation does not limit itself to shifting the focal plane, but it shifts the posterior node of the objective also. With suitable adjustments, strive to focus the image on the face of the slide which is in contact with the guides of the film and, at the same time, to center the node on the rotation axis of the drum. Do not be surprised if these operations take you a week of work. Why 70 meters and not Infinity? Because in this way you will obtain a greater depth of field and you will have both distant objects and objects quite close in focus. Due to the comparatively low exposure time, under sun light you will have to use a diaphragm aperture between f16 and f22. These apertures will allow you a wide depth of field.

Filters.
We assume that you will use this camera to make color pictures. As you know, the more distant the objects are, the more they tend to become hazy and blue, moreover the ultraviolet rays increase. To avoid the prints becoming too blue and to lower the effect of haze on the pictures, mount on the objective a filter with a slight amber color. You can also try to add a polarizing filter to lower the reflections and increase the saturation of the colors.

Blackening the Internal Surfaces.
To prevent parasitic light from entering the camera and to lower the reflections of the light which passes through the objective during shots, you must blacken the internal surfaces of the camera. For this purpose, you can use an aerosol paint of flat black color. Do not put paint on the guides of the film.


MEASURING THE SPEED OF ROTATION

At maximum spinning speed of the drum, a point on the film should be exposed for about 1/60 of a second. If necessary, modify the diameter of the wheels of the rotation system. To measure the exposure time (t), raise the Plexiglas lid so the microswitches do not stop the turning of the drum. Let the drum rotate for 20 seconds and count the number of turns it makes (w). The exposure time it is given by: t=1/(w3). If for example w=10, t=1/30". This formula is valid for the geometry of this camera. You can consider the rotation speeds to be inversely proportional to the diameter of the wheels on the axle of the electric motor, so if you obtain 1/60" with a wheel of 8 mm in diameter, you will have 1/30" with one of 4 mm and 1/15" with one of 2 mm.


USING THE CAMERA

EXPOSURE

On a day with normal sun, a film speed of 100 ASA and an exposure time of 1/60", you have to set the diaphragm to f16. As the objective is inside the drum and you are unable to read the values of the diaphragm, you will have to adjust the diaphragm by measuring the diameter of its pupil, or hole for the passage of the light. As the f number of the diaphragm corresponds to the ratio between the focal length (F) and that diameter of its pupil (d), the diameter of the whole will be given by: d=F/f. To obtain a diaphragm of f16 with a focal length of 75 mm, you have to adjust the pupil of the diaphragm to 4.7 mm in diameter. As batteries run down, you can tighten the opening of the diaphragm a bit. Never open the diaphragm larger than f16 because the closer objects will go out of focus. Instead use a lower rotating speed. At the seashore or in landscapes with snow, tighten it to about 3 mm. If necessary, use an incident light exposure meter. In practice, the diaphragm of this camera has to be set by using a stick. As during this adjustment the film would be exposed and ruined, this operation can be made only when the film is removed.


TO SHOOT

Once you have found a landscape which you wish to record, then set up your tripod, mount and level the camera, determine with the viewfinder the right and left limits of the frame, lock the tripod head, insert the power supply cable, and open the front window. At this point, you are ready to take shots. Sometimes, it is necessary to wait for a bus to go away, or the sun to come out from behind a cloud, etc.. We have noticed also that almost always, if you wait some minutes, something happens or someone comes which might make the picture better. After you have stopped bustling about, setting up this apparatus, people who are a little curious, will forget you and resume activities: some to converse, others to work or read the newspaper, etc.. At this point, your camera is ready to record a scene which will tell many things about the relationships of persons with each other and with the urban or natural environment in which they are.


CHARACTERISTICS OF THE SHOTS

One of the first things you will notice is that, on the prints, the horizontal lines of the buildings will become bent. This happens because the intersection of an object's straight lines with the cylindrical surface of the film makes parabolas. In a normal camera, where the film is flat, the intersection of the straight lines with the plane surface of the film forms straight lines. In our shots, the vertical lines will remain straight because they fall on the generatrix of the cylinder, which is rectilinear. The bending of horizontal lines and in a lesser way of inclined lines is the price we have to pay to obtain a wide field of view. In compensation, we also obtain advantages. Now has come the time to say some words about perspective.


THE PERSPECTIVE

What is perspective? Perspective is a way to represent three-dimensional reality on a two-dimensional plane. A sculptor has no problem representing dimensional reality because his portrayals have three dimensions. Neither do those who build models of buildings or cities have problems with perspective. Painters and photographers instead depict reality on two-dimensional surfaces. This is handy because plane surfaces can be easily placed in archives and need less space than statues or models. There are three main types of perspective: linear, cylindrical, and spherical. They all allow you to depict three dimensions on a plane surface, but each of them has its own merits and drawbacks.

In linear perspective, also called renaissance perspective, all the orthogonal lines are rectilinear and they converge in points called vanishing points which are usually placed on the horizon line. Most cameras which keep a flat film plane work on linear perspective. When the field of view is small, this type of perspective works well and it has no noticeable disadvantages. When instead the angle of the shot is wide, the objects in the center of the picture are made to appear smaller in relation to those at the borders. This happens because the distance between the objective and the center of the picture is smaller than the distance between the objective and the border of the picture (figure 3) and the reproduction ratio of the objects is directly proportional to these distances. As a result, the objects placed in the center of the picture appear to be far away. Scenes shot with a wide angle objective seem to become deeper. For example a monument placed in the center of the picture will look rather insignificant. Mountains are made to look far away by a wide angle objective and, if you shoot them with the camera turned upward, they will also look to be squashed downward and turned into little hills. Any lack of chromatic fidelity of the prints will complete the ruin, and the picture which you were expecting to portray a spectacular landscape will be so banal that you will be tempted to throw it away. Moreover, with linear perspective it is impossible to shoot a field of 180 degrees simply because you would need an infinitely large film. In conclusion, linear perspective is useful for narrow fields, while for wide fields it alters the ratio of the sizes of the objects.

http://www.sanford-artedventures.com/create/tech_1pt_perspective.html    One-point perspective
http://www.sanford-artedventures.com/create/tech_2pt_perspective.html    Two-point perspective

To understand cylindrical perspective, imagine yourself with the task of drawing a wall some meters high, which extends as far as the eye can see both to your right and to your left. After having surmounted your initial disorientation, you will probably draw a horizontal straight line which will represent the base of the wall. Then you will fix a point on the left side and you will draw from there an orthogonal line for the upper border of the wall, then you will do the same thing on the right side of the sheet. You will have two inclined straight lines which tend to cross at the top (figure 38), but you will find yourself in trouble because in this position the wall has no corner! It has a horizontal line! But, if you draw a horizontal line, there will be two corners! How can you solve this problem?

 

Cylindrical perspective

 

If you carefully observe the upper border of the wall, you will notice its slope toward the left vanishing point increases as you look away from the center. The same thing happens at the right side and, as there are no discontinuities, the line you should draw has to be curved, in particular it should be a parabola. You will have a curved orthogonal line, but you have been allowed to draw an infinitely long wall on a sheet of finite size. By means of vertical straight lines, you can also draw doors and windows on the wall. Hopefully, you will not often have to shoot walls so long. Usually, even with this camera spaces are shot in which buildings are relatively far away, or seen from a corner. In any case, notice that one of the advantages of this type of perspective is that it respects the ratio among the sizes of the objects.

You can consider spherical perspective as an extension of cylindrical perspective. Imagine yourself to be halfway up a skyscraper with the task of drawing another skyscraper in front of you. You will have the same problems you had in drawing the wall, except they are shifted in the vertical direction. Now, if you want to draw something which is very wide, you have to bend the horizontal lines as much as the vertical ones. In this way, you will obtain a representation of spherical perspective. There are objectives called fish-eye lenses which are able to cover a field of view greater than 180 degrees on a film plane. Pointing the camera vertically with this objective, you can shoot everything around you for 360 degrees. With an objective working in linear or cylindrical perspective, you never would be able to take in a field so wide.

We hope these descriptions have illustrated in a simple away the main characteristics of these three main perspectives. Each of them corresponds to exact mathematical relations. Once you understand their advantages and limits you will not call lines represented by cylindrical or spherical perspectives bent or distorted, but rather orthogonal lines drawn according to different methods.


TO SHOOT IN CYLINDRICAL PERSPECTIVE

No one forbids you to shoot a building square on from the front so as to warp its lines in an abnormal way. No one forbids you to tilt your camera downward in order to make the horizon line become convex, or upward to become concave. These things have been done of course, for one reason or another, but I prefer to use cylindrical perspective so as to exploit its advantages and minimize its disadvantages.

This camera has various merits, for example the comparatively large format of the film allows you to record very fine detail. Perhaps the biggest merit of this camera is its ability to record a wide field of view and, at the same time, to record objects at the same distances and proportions that you observe them with the naked eye as well as keeping vertical lines straight and vertical.

The image format provides its own unique equilibrium. The camera has a horizontal field of view about three times the vertical one. This fits well to the natural disposition of things which are near the line of the horizon. Accurate linear perspective for the vertical lines fits well with the relatively limited field in the vertical direction.

As this camera has a field of view of 120 degrees, if you place it in a corner of a rectangular room, you can shoot all four sides at once (figure 39).

Given its wide angle of view, this camera depicts very well the type of day, its weather and its peculiar type of light. With a normal camera it is not always possible to know if the type of light you see in the print corresponds to reality or if and how much it has been influenced by photographic processes.

Soon you will notice that the field of 120 degrees is very wide and you will have difficulties finding landscapes wide enough for the camera. Often you will find unphotogenic things encroaching on your view such as parked cars, coaches, telephone poles, trolley bus cables, traffic signs, power lines, and trash cans... Alas! a wide field of view makes these things even harder to exclude from your shots. City councils should pay closer attention to managing the views of their most important places and buildings.

As we said, the main disadvantages of cylindrical perspective are to make horizontal lines of close buildings into parabolic lines and to make plane surfaces look cylindrical when they are shot from the front. Figures 40 and 41 offer some ways to avoid those distortions.

 

How to shoot a place or a room

Correct way to shoot a building

Correct way to shoot a building

 

Analysis and Synthesis.
With a normal camera, particularly with a telephoto objective, the subject is in some ways removed from its context. If you photograph a person, you do not see much of what surrounds him. The same is true for a building which is removed from any of its surrounding area which is not included in the shot. For example, we are accustomed to seeing the Milan Cathedral so well cut off from its environment that we never have been able to understand where it was placed. In our article, "Some panoramic pictures", you can see the picture of this cathedral, made with the panoramic camera we are describing. In this picture, the cathedral is placed near other buildings, in a wide place where there are tourists and passersby. Counter to what happens with normal cameras, this camera includes the context with the subject and brings it back into its environment. In this case, it is not even correct to speak of "a" subject anymore. In fact, a panoramic shot gathers a plurality of subjects which participate in the comprehensive view. To this purpose, it is possible to say that while a normal camera performs an operation of analysis, removing the subject from its environment, this camera makes an opposite operation of synthesis, in which the different parts are put together again, in which they are brought back into their environment, where they live one with the other. From the analysis of the single parts, the attention is now shifted to the rapport among the parts and to the comprehensive view.


OBSERVING THE PICTURES

As a general rule, these 120-degree pictures should be observed from such a distance as to fill 120 degrees of the observer's field of view. Don't print them too small because the space will be compressed in an unnatural way and the whole scene will suffer for it. To obtain a correct rendition of the "space" you have photographed, it's necessary to print these pictures quite as large as you can. Moreover, they should be observed close up, so that the viewer's field of view is similar to the 120 degrees of the shot. Perfectionists would even keep the prints arranged in a cylindrical way with the horizon line at the eye's height. This can be done, but it is not necessary because the prints can be observed as well by keeping them in a plane.

Prints on Photographic Paper.
You can print these pictures like all other photographic pictures, but because they have a nonstandard format, you will have to find a lab equipped to print them. We suggest a minimum size of 80 X 29 cm. You can collect these pictures in suitable albums which you can fabricate yourselves. The album we show in figure 42 is made up of a plywood sheet on which are assembled two clips from ring binders. Prints are mounted on cards by means of double sided tape. A cover of suitable material completes the album.

If you want your prints to last a long time, remember to ask the lab to fix and wash your prints well. A badly fixed or insufficiently washed print can change color even after only a year. If it is well processed, it can keep its colors even after 20 years or more. Negatives and color transparencies as well have to be well processed in order to last. Because of their wide format and their hand processing, the printing of these pictures is costly and unfortunately it is not always done properly. Often, some dominants remain on the pictures and they ruin the image by hiding its slighter nuances of color. To hang pictures on the walls, you can mounted these prints on chipboard panels with white borders.

 

Album for panoramic pictures

Figure 42 - Album for panoramic pictures. Prints have the size of 90 x 32.6 cm.

Color Transparencies.
This camera is suited also for color transparencies. They have the advantage of being able to be viewed directly, without having to print them. To this scope, you have to build a suitable viewer provided with a lens to magnify the transparencies. The drawbacks of color transparencies are that they do not allow exposure errors, they do not have as much exposure latitude as negatives, and it is expensive to make prints from them.

Digitization.
Negatives and color transparencies can be digitized by means of scanners. The resolution of color negatives can be considered to be 50 lines/mm, which corresponds to about 1270 dpi. Scanners with the resolution of 1200 dpi are on the market and they are quite cheap. Check that the scanner really has the resolution asserted. Check also if it allows digitizing transparencies or films and if it allows shooting the whole format of your film. Often, these scanners are provided with masks for the different film formats. As the 60x160 mm format does not exist, you may have to make a suitable mask. To avoid Newton's rings, keep the film slightly raised from the glass. After this operation, you can observe your pictures and modify them by means of computers.

Prints on Paper of Digitized Pictures.
Once you have digitized them, you can print these pictures with ink jet printers but the technology of ink jet printers is still quite primitive. Colors are not saturated enough and not true, the pigments of the inks are not resistant to fading and they are dissolved by water. Dye sublimation printers are better but more expensive. I am afraid though, that most home printers do not allow you to print on the long paper required for wide angle formats. To obtain larger dimensions, you can use special printers or plotters. Before you order expensive large format prints, made on special shiny papers, do some tests and ask for an estimate.


IMPROVEMENTS

The panoramic camera we have described is the model which we have built, but it is possible to imagine other designs. As we have already mentioned, an interesting improvement would be an electronic control of the rotation speed of the objective which would give us the possibility of a wider range of exposure times. Another improvement would be to allow the operator access to the objective to replace filters and to set the diaphragm more comfortably. Film type 220, which is longer than 120, could be used with the advantage of having to replace the film less frequently. Finally, it could be possible to use a CCD from a scanner instead of film. In this case, it would be necessary to solve several problems, such as determining the transfer speed of the image onto the memory card. However, even the way it is, this camera is able to take shots which you will certainly be satisfied with.


MAINTENANCE

Apart from replacing batteries, the main maintenance is to periodically replace the rubber belts of the drum rotation device, because after some years, these belts can degrade and compromise the working of the system. As the objective is well protected, it is not necessary to clean it any more than every few years.


INTERNET RESOURCES

http://panphoto.com/cameras.html   Panoramic Camera Information, description of the main models of panoramic camera.
http://www.rit.edu/~andpph/text-strip-experiments.html   Panoramic Camera's I've Made (by Andrew Davidhazy)
http://www.cirkutpanorama.com/cameras.html   Panoramic Cameras (interesting historical profile (description?))
http://memory.loc.gov/ammem/pnhtml/pnhist1.html   A Brief History of Panoramic Photography, Part 1
http://www.panoramic.net/www/HandBuilt.htm    Hand Built Panoramic Cameras
http://perso.club-internet.fr/montjay/panorama_e.htm   Panoramic Camera
http://www.mottweilerstudio.com/    Pinoramic Camera (with pinhole objective)
http://www.e-pan.com/  Digital Panoramic Camera
Internet Resources (panoramic cameras): panoramic camera
Internet Resources (perspective): perspective vanishing point
Internet Resources (pin-hole cameras): pinoramic camera, pinhole camera


CONCLUSION

To build this camera is quite a demanding exercise, so we have also included in this article some methods for taking panoramic pictures within everyone's reach, such as the use of a wide angle objective, a sequence of shots, and the nice Pinoramic camera.

Even if making this camera is not easy, we think it is a challenge which a person keen on photography will surely find worth completing. Builders will also have to be ready to have a rebellious camera which will not always do what they want, but which will lead its builder to look for landscapes, to analyze them under many aspects and to see them as a whole. The best use of this camera is not for shooting single objects, or things which other cameras are able to do better, but for shooting spaces, light, weather, ambiances, the relationships among buildings, the relationships between the buildings and the urban environment where they are placed, the way people react to the spaces, by walking in a hurry and hanging their heads, by watching with nose upwards, or by pausing a little, by sitting or lying down. Your pictures will guide those who will observe them to read reality in a different way.

 

Venice, Canale della Giudecca

Figure 43 - Venice, Channel of Giudecca, 16 may 1979. This picture has been made with the camera we have described. Here you see it reduced by 10 times, but if you click on it, it will recover its original size. We warn you that the image you are preparing to download, even if compressed "jpg", is of 4.3 Mbytes. See the right hand of the mariner, it seems he holds a cigarette. In order to see the picture in the original size, click on it.

 


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