Film Exposure
Film exposure speaks to the amount of light that strikes the film when you press the shutter button to make a picture. Correct exposure depends on letting just enough light to enter the camera for the film to record the scene accurately.
Too little light reaching the film is called underexposure; too much light is called overexposure. Just the right amount is a good exposure. negative print
Too little light reaching the film is called underexposure; too much light is called overexposure. Just the right amount is a good exposure. negative print
Too little light reaching the film is called underexposure; too much light is called overexposure. Just the right amount is a good exposure. negative print
Both an under and over exposed negative will cause a range of problems that will make producing a good print difficult (or impossible) so getting a properly exposed image is pretty much the most important technical aspect of photography.
An underexposed negative will have received too little light to record the image in full detail. Most likely only the brightest areas, the areas that reflected the most light, will have recorded and all the shadows and even the details within the bright areas were not recorded and will be lost. not enough light = not enough information
An overexposed negative will have received too much light and so all the details, especially from the areas that were reflecting the most light, will be blocked up with dense layers of silver. These details will be extremely difficult to print and some may not be able to print at all. too much light = too much information
A properly exposed negative will have received just the right amount of light needed for the subject in its current lighting conditions to record the details in the areas that reflected the most light (the highlights) and the areas that reflected the least light (the shadows); making these negatives a breeze for printing as all the information is present and none is blocked up by too much silver. right amount of light = right amount of information
There are three main factors that you need to understand in order to control the amount of light exposure your film receives, and in doing so you'll be able to control the quality of your film exposure and get good, easy, workable negatives. film speed light sensitivity aperture intensity of light exposure shutter speed length of light exposure
Film Speed
Film speed is the measurement of how sensitive a particular film is to light. A film that is highly sensitive to light is referred to as a fast film; a film with low sensitivity is referred to as a slow film.
The most common way to talk about film speed is according to its ISO (aka: International Standards Organization) rating. i s o rating
A film with a higher ISO number (a faster film) needs less light to properly capture an image in its emulsion than a film with a lower ISO number (a slower film). Slower Faster
This means that a roll of ISO 400 film is 4times more sensitive to light than a roll of ISO 100 and so it will take 4times more light to properly expose ISO 100 film as it will take to properly expose ISO 400 film (400 100 = 4). Slower Faster
Film speeds can be broken down into the categories of slow & medium (mostly used for brightly lit still subjects), fast (most often used in various types of outdoor lighting, indoors, sports and action subjects), & ultrafast (mostly used for very dim conditions or super fast action shots). i s o r a t i n g 50 100, 125, 200 400, 800 1600 3200 = = = = c a t e g o r y slow medium fast ultra fast
The tricky thing with film speeds is the more sensitive the film is (higher iso), the more grains of silver there are on the films emulsion; making fast films produce a much grainier image than slow films. Robert Capa
The tricky thing with film speeds is the more sensitive the film is (higher iso), the more grains of silver there are on the films emulsion; making fast films produce a much grainier image than slow films. Sally Mann
Aperture
All lenses have an aperture, an opening created by a series of overlapping blades that allows light into the camera. Your aperture determines how wide the lens opens when you take a photograph: the size of the window that you re opening to allow light in.
Film of a given speed (sensitivity to light/iso) needs a very certain amount of light to record an image: not too little & not too much. By adjusting your aperture opening, can open it up to allow more light in or close it down to reduce the amount of light that passes through and into the camera.
A wide (or large) aperture opens the lens more, allowing a greater amount of light to hit the film. A narrow (or small) aperture allows less light to hit the film.
A wide (or large) aperture opens the lens more, allowing a greater amount of light to hit the film. A narrow (or small) aperture allows less light to hit the film.
The size of your aperture opening for a particular shot will depend on the amount of light that you re shooting in: you ll need a relatively large (wide) opening in low-light conditions to allow enough light in to expose the film, and a smaller opening in brightly lit conditions so you don t let in more light than what is needed.
Aperture openings are measured in f-stops and f-stop numbers are counter intuitive. A higher f-stop number indicates a smaller lens opening, which means that less light passes through; a lower f-stop number indicates a larger lens opening and more light passing through.
Aperture openings are measured in f-stops and f-stop numbers are counter intuitive. A higher f-stop number indicates a smaller lens opening, which means that less light passes through; a lower f-stop number indicates a larger lens opening and more light passing through.
Aperture openings are measured in f-stops and f-stop numbers are counter intuitive. A higher f-stop number indicates a smaller lens opening, which means that less light passes through; a lower f-stop number indicates a larger lens opening and more light passing through.
Aperture openings are measured in f-stops and f-stop numbers are counter intuitive. A higher f-stop number indicates a smaller lens opening, which means that less light passes through; a lower f-stop number indicates a larger lens opening and more light passing through.
Aperture openings are measured in f-stops and f-stop numbers are counter intuitive. A higher f-stop number indicates a smaller lens opening, which means that less light passes through; a lower f-stop number indicates a larger lens opening and more light passing through.
Aperture openings are measured in f-stops and f-stop numbers are counter intuitive. A higher f-stop number indicates a smaller lens opening, which means that less light passes through; a lower f-stop number indicates a larger lens opening and more light passing through. f/1.4
Something to keep in mind is that f-stops have a proportionate relationship. typical range of whole stops f1.4, f2, f2.8, f4, f5.6, f8, f11, f22
A whole, or full, f-stop will have a half and double relationship to its neighbor (ex. f/8 lets in twice as much light as f/11 and half as much light as f/5.6.) When you open your lens up one full stop, you double the amount of light entering the camera & when you close it one full stop, you half the amount of light. typical range of whole stops f1.4, f2, f2.8, f4, f5.6, f8, f11, f22 = 2x as much light as
A whole, or full, f-stop will have a half and double relationship to its neighbor (ex. f/8 lets in twice as much light as f/11 and half as much light as f/5.6.) When you open your lens up one full stop, you double the amount of light entering the camera & when you close it one full stop, you half the amount of light. typical range of whole stops f1.4, f2, f2.8, f4, f5.6, f8, f11, f22 = 2x as much light as = ½ as much light as
Some lenses also have half, or partial stops, meaning it is a setting in between two whole f-stops. Even if your lens doesn t have these numbers on its aperture ring, for more precise exposure control, you can deliberately set your aperture in between whole f-stops. typical range of whole stops f1.4, f2, f2.8, f4, f5.6, f8, f11, f16, f22 half stops f1.7, f2.4, f3.4, f4.8, f6.7, f9.5, f13.5, f19, f27
Shutter speed
Your camera contains a shutter which is a curtain (or sometimes set of blades) that blocks the light from reaching the light-sensitive surface of the film. When you take a picture, the shutter opens to allow light to reach and expose the film, and then closes again.
The amount of time that the shutter stays open before closing again is an adjustable interval called the shutter speed and it determines how long the light hits the film when you take a photograph: the other factor in how much light the film is exposed to.
A fast shutter speed opens the shutter for a short amount of time allowing less light to hit the film; a slow shutter speed opens the shutter for longer, allowing more light to hit the film.
Shutter speeds are measured in seconds. Most shutter speeds are fractions of a second although they're shown as full numbers on your camera (ex: 500 on your camera indicates 1/500 of a second. The 1/xxx is dropped for simplicity). Shutter speeds longer than one second are usually indicated by the symbol after the number on the LCD screen, or by a different color on the control wheel. typical range of shutter speeds 1, 2, 4, 8, 15, 30, 60, 125, 200, 500, 1000 1 second, 1/2 a second, 1/4 of a second, 1/8 of a second, 1/15 of a second, etc...
Like f-stops, shutter speeds also have a proportionate relationship and will have a half and double relationship to its neighbor: (ex. 1/30 lets in twice as much light as 1/60 and half as much light as 1/15). When you slow your exposure by one shutter speed, you double the amount of light reaching the film & when you speed it by one shutter speed, you half the amount of light. typical range of shutter speeds 1, 2, 4, 8, 15, 30, 60, 125, 200, 500, 1000 = 2x as much light as
Similarly to apertures, shutter speeds also have a proportionate relationship and will have a half and double relationship to its neighbor: (ex. 1/30 lets in twice as much light as 1/60 and half as much light as 1/15). When you slow your exposure by one shutter speed, you double the amount of light reaching the film & when you speed it by one shutter speed, you half the amount of light. typical range of shutter speeds 1, 2, 4, 8, 15, 30, 60, 125, 200, 500, 1000 = 2x as much light as = ½ as much light as
The setting for your shutter speed for a particular shot will depend on the amount of light that you re shooting in: you ll need a relatively slow (long) exposure in low-light conditions to allow enough light in to expose the film, and a faster exposure in brightly lit conditions so you don t let in more light than what is needed. 1, 2, 4, 8, 15, 30, 60, 125, 200, 500, 1000
The setting for your shutter speed for a particular shot will also depend on your aperture setting. Since your film requires a very certain amount of light to record an image, if you were to have your aperture closed all the way down (letting in less light) in normal lighting conditions, your light meter will most likely not balance out until you slow your shutter speed down (letting in more light). f22
The setting for your shutter speed for a particular shot will also depend on your aperture setting. Since your film requires a very certain amount of light to record an image, if you were to have your aperture closed all the way down (letting in less light) in normal lighting conditions, your light meter will most likely not balance out until you slow your shutter speed down (letting in more light). f22 @1/3o
There is a reciprocity that exists between these settings that you utilize in order to find the appropriate balance (intensity of light + length of exposure) for the conditions at hand; facilitating just the right amount of light to reach your film for just the right amount of time. exposure = intensity time
And once you find just the right amount of light (i.e., the light meter is happy), by adjusting one setting in a particular direction, while adjusting the other by the same amount in the opposite direction, you maintain the same total quantity of light striking the film. f 16 @ 1/30 f 11 @ 1/60 f 8 @ 1/125 f 5.6 @ 1/250 f 4 @ 1/500
This reciprocity means that you can make the lens aperture one stop smaller (letting in half as much light to strike the film), but lengthen the shutter speed by one stop (letting light strike the film for twice as long) and maintain the same overall exposure (balance of light). f22 @ 1/15 = f16 @ 1/30 = f11 @ 1/60 = f8 @ 1/125 = f5.6 @ 1/250 = f4 @ 1/500 = f2.8 @ 1/1000 s m a l l ap e r t u r e + s l o w sh u t t e r sp e e d l a r g e ap e r t u r e + f a s t sh u t t e r sp e e d
As we get more technical, this will come in exceptionally handy. But for now, just remember that each of these elements work together to define just how much light reaches the film to get the right amount to create a good exposure: a good photograph. f i l m sp e e d s h u t t e r a p e r t u r e