Art 50/150
Black&White Photography

Basic Camera Operation

The single lens reflex (SLR) 35 mm camera utilizes the camera lens itself for composition and light metering. You are actually looking through the lens at the image that will be recorded on film (though you should allow for the fact that the negative will contain about 2% more than what you see). This is achieved by the work of a small mirror that drops down in front of the shutter. In normal operation, light coming in through the lens is reflected off the mirror surface and up into the metering screen and eyepiece at the top of the camera. In order to see the image as clearly as possible, the SLR keeps the lens aperture fully open while adjustments are being made. Then, at the moment of exposure (shutter release), the mirror flips up, clearing the path to the shutter and film; the aperture is closed down to the selected value; and the shutter opens-and-shuts at the selected speed. All three events combine in a fraction of a second and create the characteristic sound of an SLR camera taking a picture.

Black&White photography is based on camera work, which creates a B&W negative, and darkroom work, which creates a B&W print. Both involve substantial dimensions of creativity once the basic techniques have been mastered. In this essay, I will discuss camera work only. Some of the more technical aspects of camera design and function will be found in the accompanying essay on Technical Camera Issues.

There are two fundamental problems involved in creating a single photographic image with an SLR camera. The first (composition) is bringing the desired light image to the film; the second (exposure) is controlling the combination of light intensity and film sensitivity to give a developed image (slide, negative, print) that achieves the desired result. The former is based on optics; the latter is based on chemistry. As background, I have included a short essay on The Chemistry of B&W Photography.


Composition is mechanically the simpler of the two problems, but it is also by far the greater creative challenge in the long run. I will consider only the mechanical issues here. The rest is what Ansel Adams called "image management" and I will discussed it at the end.

Composing the image in this simple mechanical sense means selecting a particular lens and using its features to create the image that you view through the camera's viewfinder. The modern compound lens used on an SLR camera has three relevant adjustable features --- focal length (selected with the lens or adjustable with any "zoom lens"), focus, and aperture.

The lens focal length will control the size of objects in your image and, at the same time, it will determine the volume of space included in your image. A 50mm lens is often called the "normal lens" because it creates an image in which objects are more-or-less as we normally see them through human eyes. As the focal length is reduced -- e.g., toward 28mm or even 20 mm -- the angle of incidence of light falling on the film is increased outward so that the volume of space included is greatly increased. As a direct result, the relative sizes of objects decreases. Inversely, as the focal length is increased -- e.g., toward 80mm or 105mm -- the angle of incidence of light is decreased inward so that a smaller volume of space registers on the film. Objects are relatively larger. From an operational point of view, you would choose a small focal length lens to be more inclusive within limited space (e.g., photographing the interior of a room) or a large focal length lens to bring a distant object into fuller view (e.g., a photographing a bird in a distant shrub). The obvious advantage of a zoom lens is being able to change focal length without changing the lens; the disadvantage is that cheaper zoom lenses are optically inferior to fixed focal length lenses.

Contemporary quality SLR cameras usually provide one or more programmed modes in which the camera automatically focuses and sets exposure. Throughout your work in this course you will want to turn off all of these features and use the camera on "manual" mode. Having selected the lens focal length, you are ready to focus the image. As observed above, the light incident on the film is reflected from or emitted by a host of objects within a volume of space. Not all of these objects can be focused at the same time. In fact, with the lens focus ring set at infinity, only distant objects will appear in sharp focus, and everything nearby will be blurred. As you move the focus ring away from infinity, closer objects come into focus as distant objects go out of focus. In fact, the lens focuses a group of objects within a band of volume and the width of this band is called the depth-of-field. I'll discuss depth-of-field more, but at this point you need to focus the image on the particular object(s) that are of interest to you.

The third mechanical feature of a modern compound lens is the aperture setting. The aperture setting controls the amount of light passing into the camera by changing the diameter of a mechanical iris. While the iris can be continuously changed from its widest opening (the defined aperture of the lens) to its narrowest opening, the aperture ring is typically calibrated in "stops" which you will feel as you rotate the ring. The stops are designed to reduce the transmitted light by one half each time the ring is rotated from one stop to the next, as the iris is closed. The aperture is designated as the denominator of a fraction so that a larger number means a smaller iris diameter and less transmitted light. Details of this are discussed in the technical notes; for now it is simply important to understand that an aperture of, e.g., f/8 admits twice as much light as an aperture of f/11, which admits twice as much light as f/16.

As we will see in the next section, the aperture is mainly related to the exposure of film to light intensity. However, the aperture is also related to the depth-of-field, as described above. While we can focus only a band of space within the volume that contributes to the whole image, the depth of this band can be changed by changing the aperture of the lens. The smaller the aperture, the larger (thicker) the depth-of-field; the larger the aperture, the smaller (thinner) the depth-of-field. Old lenses used to show depth-of-field markings so that one could estimate this factor; but new lenses do not tend to offer this feature. Some SLRs offer a depth-of-field preview button. While one normally sees through the fully open lens in order to set up a photograph, this button closes down the aperture to the selected value and allows you to see how well all objects in the image are focused. Since the aperture is closing there is less light passing through the lens and the image will appear substantially darker. Nevertheless, it is usually possible to view the focus on major objects.

Aperture control over depth-of-field can be used creatively in different ways. Perhaps the subject of a photograph (a portrait, for instance) is within a very narrow band of space and you want to give it emphasis by blurring out everything else. You want a shallow depth-of-field with a sharp focus on the subject. You should select an aperture for a wide open lens, e.g., f/1.4 to f/5.6. On the other hand, perhaps you are constructing an image of a landscape and you want elements of the foreground to be in focus along with objects at infinity. You should select the smallest opening possible for your lens, e.g., f/16 to f/22. As we will see in the next section on exposure all of this is limited by lighting conditions since every aperture stop means halving or doubling the amount of light reaching the film.

In sum, the mechanical factors involved in composing an image are (1) selection of a focal length (size of objects in image), (2) focus down on the principal object(s) (image sharpness), and (3) depth-of-field (volume of the three-dimensional object complex that remains in focus). Having dealt with these factors, we are ready to proceed to the issue of film exposure.


Under the concept of exposure we find the total amount of light that falls on the film and whatever that does, given the film's sensitivity, in creating a slide, negative, or (ultimately) a print. The factors involved here are film sensitivity (ISO rating of the film), time span of light exposure (shutter speed), and amount of light passing the shutter per unit of time (aperture setting). Generally speaking, lower ISO ratings (slower films) lead to sharper images and less graininess. However, they also require more light and that may mean larger aperture (smaller depth-of-field) or slower shutter (blurred moving objects). Every image that you create is a compromise between all of these factors and depends upon what is most important for the particular kind of subject.

[A word about film sensitivity. Films used to be identified by their ASA (American Standards Association) rating and you will still see this mentioned in the literature. The German system was the DIN (Deutsche Industrie Norm). Today, these are combined into an ISO (International Standards Organization) rating. Numerically, these are all the same.]

Once the film is loaded in your camera at a given ISO value, you have only aperture and shutter speed left to control. Modern automated SLRs will set these for you, but you may not be happy with the result. The problem is that different parts of the image have different luminous intensity and will affect the film differently. If you were to focus on a rather dark object among generally light objects in the image, your camera might interpret the whole scene as rather dark and set aperture open and shutter slow in order to give the film more light. The resulting image would be badly "over exposed" or light. The only way to attain the exposure that you want is to set the camera at "manual." [Modern automated SLRs usually include a setting for aperture preference or for shutter preference in which you select aperture or shutter and the camera automatically adjusts the other. In manual mode, you select both.] When you do use your automatic camera on one of the programmed settings, be sure to take note of the exposure the camera is suggesting. In my own experience, automatic settings tend to favor a high shutter speed and, hence, an open aperture. While this has the advantage of preventing blurring, it clearly gives you a shallow depth of field.

Remember that, whenever the camera itself makes an exposure adjustment, it is setting the exposure based on the light intensity being measured within its metering screen and it is setting the aperture and shutter, matching the film ISO sensitivity, to make that portion of the image a standard (normal or "best") exposure. You need to know what the metering screen for your camera is. Nikon uses a 3-D matrix screen which is a comprehensively weighted multi-section screen. But Nikon also offers a traditional center-weighted screen in which only the light in a largish central circle is measured. More expensive Nikons also offer a spot metering system in which only the light at the small focusing bracket is metered. This gives one the possibility of examining the image in detail. When the camera is in manual mode, it provides an exposure meter that tells you, relative to the light traveling through the metering screen or spot, whether it is over exposed or under exposed relative to the standard exposure for that film. The quantity of over or under exposure is measured in EU (exposure units) and one EU is usually equal to one "stop" on the lens. [That is, if the film is under exposed by 1 EU, you should open the lens by one stop, e.g., from f/22 to f/16.] You may also purchase a separate light meter and ignore the internal metering of the camera. In this case, you have two options --- a light meter that measures the incident light intensity or one that measures the light intensity being reflected back at you by various objects. The latter (a spot meter) is the most useful in black&white photography.

More light enters the camera when you open the aperture or when you reduce the shutter speed. These have very different effects on the overall performance of the camera so you need to choose the appropriate combination for the image you are seeking. As discussed above, opening the aperture has the effect of reducing depth-of-field so the image will have an increasingly shallow volume of focus. When you want to keep a large depth-of-field, the exposure has to be increased by reducing the shutter speed. Most people can hold an SLR still enough to take a sharp picture at 1/60 of a second shutter speed, but lower speeds begin to show blurring caused by hand movement. Of course, some objects are already moving too fast for even 1/60 of a second. For a still subject like a landscape it may be possible to increase the exposure by radically lowering the shutter speed and yet keep the image well focused with a large depth-of-field. This can only be done by using a sturdy tripod and a cable shutter release.

The standard aperture settings and shutter speeds are related to each other for convenience. As a matter of fact these are also related to the ISO film sensitivity. Remember that each stop of aperture opens the lens to twice as much light as you work your way down in f/ numbers. Thus, from f/22 to f/16 or from f/16 to f/11 opens the lens to twice as much light. [Incidentally, any lens, no matter what it's focal length, transmits the same amount of light at a particular aperture.] The standard sequence of stops is f/1, f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22, f/32, f/45, . . .

The shutter is also set up in standardized increments of speed and, like the standard aperture settings, or stops, the shutter is designed to alter the transmitted light in factors of two. Thus, shutter speed of 1 second is followed by 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, . . . Since the shutter speed and aperture stops are equal in light intensity increments, the camera can be adjusted without further metering once you know that one exposure combination is correct. In other words, if you know that the combination of 1/60 shutter speed with f/8 aperture gives the correct exposure, you can increase the shutter speed to 1/125 in order to avoid blurring of moving parts of the image and compensate by opening the aperture to f/5.6.

ISO film ratings are incremental in light sensitivity by a factor of 1/3 of an aperture stop. Thus, the standard ISO scale is 64, 80, 100, 125, 160, 200, 250, 320, 400, . . . If you replaced ISO 64 film with ISO 125 film, which is three steps more sensitive, you would be able to close the lens aperture by one stop, reducing the incident light.

There are some standard rules for exposure and these might come in handy if you have to work very fast or if your camera's meter fails to work. The first and most definite rule is called "Sunny 16." In bright sun (with the sun at an angle greater than 20 degrees above the horizon) the proper exposure for any film is f/16 and 1/(ISO shutter speed). In other words, if you have loaded your camera with ISO 125 film and you are photographing objects in bright sun, you can set your aperture at f/16 and your shutter speed at 1/125 of a second and expect to expose the film appropriately. This works so well that you can use it in the field to check the performance of your camera's metering system. Just allow the camera to determine the proper exposure in a sunny situation and check to make sure that it is equivalent to the Sunny 16 rule. If you set your camera for Sunny 16, you can decrease the aperture or increase the shutter speed to enhance depth-of-field or freeze moving objects by compensating the change one stop with the other. Under hazy sun, open the aperture one stop; under bright clouds, open another stop; and with heavy clouds or open shade, open yet another stop. These rules are clearly less reproducible. [It is interesting that the proper exposure for the full moon is also Sunny 16 since, after all, it is illuminated by direct sun. Of course there may be many other objects less well lighted in your total subject.]

In color photography, you must remember that luminous intensity and chromaticity are different aspects of the objects you see. When you take a photograph in direct bright sun, the film is overwhelmed by the luminous intensity and loses its overall sensitivity to chromaticity. To create a color image with elegant chromatic relationships, you are much better off making the exposure at lower luminous intensity. This is accomplished by making the exposure at sunrise or sunset or on a lightly clouded day, depending upon the subject. Sunrise and sunset offer the advantage that the sky (if that is part of the subject) is often colored in more interesting ways.

Creative Aspects: The Zone System

The Zone System in black&white photography was created by Ansel Adams and it takes the whole issue of exposure to its creative limits. One has to begin by visualizing the so-called gray scale. This is a progression of gray shades from pure black to pure white. Clearly, the progression can have as many elements as one has the patience to create. Adams constructed a gray scale with eleven elements coordinated with the lens aperture settings, or stops. Pure black is set at 0; pure white is set at X; and the mid-scale gray, or standard exposure for normal black&white films is set at V. You can buy a standard "middle gray card" which is about the size of an index card and you can carry it with you. The standard gray card is an example of Zone V.

The gray scale provides for reduction of light by up to four stops to attain increasingly dark shades IV, III, II, and I. Equally, it allows for increase of light by up to four stops to attain decreasingly dark shades VI, VII, VIII, and IX. 0 and X fall outside of the normal film capacity, and I and IX define the threshold of B&W film sensitivity. In fact, Zones II and VIII bracket the photographer's effective range of creativity because textures are only just beginning to be defined in this region. The true working range for B&W (and most color) photography is from Zone III to Zone VII. This is a range of five stops in aperture. [One should remember that a standard increment in shutter speed can always be used instead of one aperture stop, all other factors being equal.]

The standard setting on SLR metering systems as well as hand-held exposure meters is the mid-scale gray or Zone V. This means that whatever object(s) you point the camera metering system onto will print as Zone V gray if you accept the camera's exposure setting. This may or may not be appropriate and that is where all of the creativity in B&W photography begins.

After defining the Zones in terms of the gray scale, Adams discusses what he calls "place and fall." In order to execute this procedure, you should be able to set your camera on "manual" or at least be able to lock the exposure. The metering screen should be at least restricted to a center-weighted circle. A spot metering system is best. The principle involved here is based on the fact that almost any interesting B&W image will include objects of different luminosity. The amount of light exposure will entirely depend upon which object(s) is(are) selected for metering to the standard exposure for the film. In effect, when the metering system is placed on an object in the viewfinder and the camera's exposure recommendation is accepted, that object is being "placed" at Zone V and will print (in normal development) as the middle-scale gray. All other objects included in the image will "fall" on one or another of the other zones depending only upon how their luminosities compare to that of the target object.

If you are not sure what object(s) in a composition you want to meter the exposure to, you can set the camera's exposure by pointing the camera metering at your standard gray card and accept the camera's indicated exposure. (This presumes that the gray card is in the same lighting situation as your subject.) You must lock in that exposure before you return to compose and focus your picture.

If there is an object in the image being considered that you feel should be middle-scale gray in the final picture, this is the object that you should set your exposure for. This may not be the object on which focus should be locked. Therefore, you should either use the camera manually or utilize your camera's locking features to both lock the focus appropriately and then move to the other object where exposure can be set and locked also. The final step in any such process is, keeping focus and exposure locked, move the camera to compose the total image and release the shutter.

Perhaps all of this can best be understood by considering some extreme situations. Suppose, first, that the picture you are considering includes a large flat black surface being held by a person in an otherwise normal lighting situation. Suppose, then, that you aim the camera's metering system into the black surface and proceed to open the aperture and slow down the shutter speed in order to expose the film correctly according to the camera's metering system. This means, in effect, that the camera is "trying" to make the black surface middle-scale gray in the ultimate picture. In the process of doing this the camera will have to allow so much light in that the comparatively higher luminosities of all the surrounding objects will burn out or over-expose those objects completely, making them fall in very high zones.

Similarly, if the metering device were set for normal exposure while aiming at the most luminous object in the scene, e.g., the bright sky, the camera would be trying to limit the light coming from this object so that, in the final print, it would be middle-scale gray, Zone V, and the consequent reduction of transmitted light would make all of the other objects fall into Zones well below V. The print would be badly underexposed for these objects. You can demonstrate these situations to yourself easily by making three or more pictures that you have exposed in these ways. Just remember that, when your camera sets the optimum exposure, it is trying to make the object you are pointing at middle gray!

A very interesting test, recommended by Adams, is to experiment with the quality of texture available in the low Zones. In Zones 0 and I, there is usually no recognizable texture. In Zone II, we begin to see some texture; and in Zone III, detailed texture can be seen even though the object remains dark. This can now be used as a criterion in setting the exposure for any image. Pointing the metering device at dark objects in the prospective image, one can "place" these objects on Zone II or on Zone III depending on whether one wants a hint of the object's texture to show or one wants the object's full texture. Having set the camera's exposure in this way, all other objects will "fall" in the Zones appropriate to their luminosities.

The technical question here is how one "places" a dark object in Zone III when the camera's auto-exposure system is set to place it in Zone V. But the answer is clear and simple. Zone III, given the scale's structure, is two stops down (under-exposed). If the metering device shows graduations of exposure units (EU), you just set the shutter speed and aperture for the total effect of two units under-exposure. Otherwise, find the setting where the dark object would be standard exposure and then close the aperture back down by two stops.

The best way to gain some control over this procedure and to understand its creative impact on the images that you create is to examine various B&W images that you have created with a gray-scale strip and identify the Zones in which various objects fall.

While the strategy suggested above for shadows in B&W photography works well, the inverse strategy is more useful for color photography. In exposing color film you should search for the most luminous objects and set them in Zones VII or VIII, depending upon how much texture you want to see.

Filters can be used to change the natural luminosity relationships between various objects in a scene. When you have done all that you can possibly do by setting the exposure relative to the luminosities that exist, the use of filters can still offer some creative possibilities. A standard problem in B&W photography, for instance, is the fact that a blue sky has very strong luminosity and will almost always fall into a very high Zone where it prints out as an uninteresting white that gives very little contrast to clouds. Since yellow is the complementary color to blue, a yellow filter will cut down on the blue light that passes through the lens and will drop the sky into lower Zones. Among other things, this will make clouds stand out in much better definition because they will remain in the highest Zone.

As another example, a green filter can be used to make green plants appear relatively lighter in an image and present more contrast with dark objects. On the other hand, if you wanted to darken green plants in an overall scene, you would choose the complementary color of green, namely, a red filter.

A polarizing filter can be used for B&W photography as well as for color photography. Rotation of the polarizer can eliminate or accentuate polarized reflections from objects. It can also darken the sky, especially skylight coming from more than right angles from the sun.

In order to use filters wisely you need to know something about complementary colors and you need to understand some facts about natural sunlight. This takes time and experimentation.

Creative Aspects: Image Management

Image management takes us back to the creative side of wielding the camera and requires long-term experience beyond mastering the mechanical features of composition and exposure. The film plane in the back of the camera is one element in a three-dimensional world. Focal length, focus, and aperture, as discussed above, will convey a sharp image of particular objects to this plane; but the preeminent decision is where to place the camera, hence the film plane, in that world.

Consider taking a photograph of a small building. You can walk around the building in a circle and inspect many different sides of it. You can move closer or back away. As you do this, you can include or exclude various other objects in the image. While the image will always include the building, the camera position will determine what other objects are also in view and what position(s) they take with respect to the building. Everything else that we have discussed is merely mechanical; here is the really creative issue. There are literally thousands of potential images that include this building. The whole creative issue, once you have decided to include this building, is how you compose it along with all the other objects that you have available through their spatial relations with it. Adams called this process "visualization" and came to emphasize it strongly in his teaching. Simply put, the artist/photographer is not merely "taking a picture" but is, rather, creating an image. As he/she sets up the camera position, thought should aim toward the resulting image and technical skills should be used to make that particular image happen.

Three good rules-of-thumb are (1) select your subject (What are you taking a picture of?), (2) compose the image to call attention to the subject (How can you arrange the other elements of the image to complement the subject?), and (3) simplify the image (How can you remove confusing and unnecessary objects from the image?). Most images have too much sky or other background. It is very easy to make images too busy. Keep asking yourself "what is my subject?" Watch out for distracting bright spots in backgrounds or objects (like poles and power lines) that protrude disturbingly through the image. Rule (3), above, is often achieved simply by moving closer and photographing merely a fascinating part of, e.g., a building. Perhaps what really called your attention was an old window and the peeling paint. Instead of picturing the whole building, the window and some portion of the wall will do.

The basic elements of composition are the same in photography as in the other graphic arts. The objects that you choose to include in the image should be balanced and their arrangement should address whatever you are trying to express --- flatness, textures, three-dimensionality, movement, etc. A common impulse is to center the subject. Auto-focus cameras usually assume this. Many subjects, however, are posed to make reference toward other objects or even empty space. A runner, for instance, moves into the empty space in front of her. If you center these objects, the image will have a disturbingly unbalanced quality. Instead, you should usually focus on the subject, lock the focus, and compose the image with the subject off to one of the sides, moving or looking into the center of the image.

In a simplistic sense, the image is your one opportunity to "say" whatever you want to say about your subject. Since you are "saying" this via object relations and B&W contrasts, you need to think through what each of the potential images expresses. My own feeling about B&W photography is that certain aspects of images are exciting no matter what the subject or message. These are sharpness, line, texture, and richness of represented Zones. I would want any B&W image to be exciting in this sense no matter what the subject or message. After this technical factor, the creativity of subject and message emerge. What you are trying to "say" about a person may be communicated by how close you approach him/her, what objects you include in the image, and how the whole complex is composed. Everyone will develop their own interests, whether they are people, animals, natural objects, textures, architecture, or whatever. This is where photography becomes personal, creative, and rewarding.

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