Using
Shutter Priority Mode
Using the shutter priority mode on a digital camera lets you set the shutter speed and the camera adjusts the aperture to maintain correct exposure.
The other function of the shutter speed is to control motion. You would use the shutter priority setting when motion control is an important factor in a photo.
The shutter speed is the main control you have to capture motion in a photo. Anything that moves during exposure can potentially cause the final image to be blurred.
If you want a moving object to be rendered very sharply in your photo, you would need to select a fast shutter speed. And if you want to show the blurring effect you’d select a slow shutter speed.
Controlling Motion
Controlling motion in still photography calls for
a few choices to be made, and in this section we’ll look mainly at the
technical choices that need to be considered. These technical factors are such things as camera movement, and how focal length, subject speed, direction of motion and distance can all affect your choice of which shutter speed you need to control motion.
Camera Movement
Camera movement happens whenever the camera is
moved while the shutter is open. It is commonly caused by not pressing the
shutter release button smoothly, but instead pushing down too quickly and too
hard. A shutter speed that is set too low increases the chances of camera movement.
When taking pictures in low light conditions, and you have chosen not to use flash, then using shutter priority to select a faster shutter speed is a good option. As a general rule of thumb, a shutter speed that is equal to the focal length of the lens reduces the chance of getting camera movement.
For example, with a 125mm lens, use a shutter speed of 1/125 of a second or faster. A tripod and a cable release are also options.
Subject Movement
Whenever you have anything moving in the scene
you’re about to photograph, your choice of shutter speed can be very important.
Subject movement can be frozen, so it appears sharp in the picture, by using a
fast shutter speed. But how fast is fast enough will depend on a number of
factors. On the other hand, capturing a sense of motion may be more effective than a sharp image, so choosing a slower shutter speed would be the better choice. Once again, several factors will affect how slow is slow enough. So lets look at these variables and see how they influence the results.
Actual Speed vs. Relative Speed
The actual speed of the subject is less important
than the relative speed. The direction of the motion in relation to the camera is
your primary concern.For example, photographing a car going 45 mph. would require a faster shutter speed if it is moving parallel to the camera, or more precisely, parallel to the film plane or image sensor.
The same 45 mph. vehicle moving straight towards or straight away from the camera wouldn’t require as fast a shutter speed.
And if it were moving at an angle towards or away from the camera, the shutter speed would be somewhere between the two previous examples. This would apply regardless of whether you were trying to freeze the motion or blur it.
The distance between the subject and your camera is another important factor that influences your choice of shutter speed. The closer the moving subject is to the camera, the faster its relative speed will be.
Therefore, a faster shutter speed is necessary when the subject is very close to the camera and a slower speed will work when the subject is further away.
The focal length of the lens you use will also influence your choice of shutter speed. A telephoto, or zooming in on your subject has the same effect as moving closer, and requires a faster shutter speed.
Using a wide angle lens would be the same as moving further away, and a slower shutter speed could be used.
Putting It All Together
The first decision you will make is do you want a
sharp image or do you prefer to use blur in the image to emphasize the motion.
Once you’ve decided this, then you must consider the direction of the motion. You might be able to reposition yourself so the motion is easier to control, but to get the best composition or good lighting you might decide that is not a good choice. Your decision will affect the shutter speed you’ll need to create the desired photos.
Next you should consider the distance factor. Moving closer or farther away might be possible, and using a telephoto or wide angle might be the best option.
Once you have chosen the best position to take the shot, then you can choose the shutter speed that will best give you the result you want.
Naturally, because of the variables involved, the only sure way to determine the exact correct shutter speed is to experiment. With experience, however, you will find that your initial choice will often be correct or very close to the correct speed to get the result you want.
The more you practice shooting motion the sooner that experience will pay off.
Camera Shutter Speeds
In this photography lecture we’ll discuss camera shutter
speeds. The shutter speed is one of the controls that determines the exact
amount of exposure your film or image sensor receives.
Shutter speed controls the time
of an exposure by controlling exactly how long the aperture remains open. The
shutter speed also has other effects on your pictures which will be covered as
well.The following is a list of the full shutter speeds, starting with 1 second:
1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000, etc.
Each of the above shutter speeds is 1/2 the amount of time as the previous speed. Many cameras have speeds that are longer than 1 second and shorter than 1/1000 of a second.
The above speeds are a carry over from the days before digital, so you’ll notice that 1/16 has been rounded down to 1/15. With digital the sequence is more commonly 1/16, 1/32, 1/64, etc. And with many modern shutters, speeds of any duration are possible…for example you may get 1/650 or 1/1200 of a second.
The shutter speeds listed above are set up similar to f-stops…each speed lets in 1/2 as much light as the previous speed, and twice as much as the next one.
This allows for different combinations of shutter speed and f-stop to be chosen to get the same exact exposure. So 1/60 at f/8 gives the same exposure as 1/30 at f/11, or 1/125 at f/5.6. The shorter the time (shutter speed) you use, the larger the aperture opening (f-stop) you’ll need to let in the same amount of light.
This can be confusing until you get used to it but with practice is becomes second nature.
A good analogy is to think of filling a container with water. If a 1 inch hose takes an hour to fill the container, then a 2 inch hose would take a half hour, a 4 inch hose would take 15 minutes, and so forth.
Each time you double the amount of water flowing in, it takes only half the amount of time to fill your container. It works the same way with f-stops and shutter speeds…a larger aperture lets in more light, so a faster shutter speed (less time) is needed.
Why so many combinations?
Well, exposure is controlled by a combination of f-stop and shutter speed, but each has another effect on the image as well. The depth of field is affected by the f-stop and sharpness is affected by the shutter speed. Depth of field is covered in another lecture, so here we will discuss how different shutter speeds affect sharpness.
Two common reasons for a lack of sharpness in photographs both have to do with movement…. one is subject movement and the other is camera movement (or camera shake as it is often referred to).
Subject movement is of course when you are taking a picture of a moving object. If your purpose is to freeze the motion and render the subject very sharp, then you would want a fast shutter speed.
On the other hand, you may wish to emphasize the motion so a slower shutter speed would be the better choice.
Camera movement is the other common reason for uns harp images. There can be several causes of camera movement. One is pressing the shutter release too hard causing the camera to jerk at the exact moment of exposure. Even a fast shutter speed may not be able to correct this habit. It just takes practice.
What shutter speed is fast enough to avoid camera movement will vary due to a number of factors.
First, it will depend on how steady you are when holding your camera. Again, practice can help. And using a faster shutter speed whenever possible is a good solution. Remember also when you are using a longer lens (a telephoto) that not only is the size of the image magnified, but the movement is magnified as well.
So with longer lenses a faster shutter speed may be needed to avoid camera movement. If you must use a slower speed then try to brace yourself and/or your camera or use a tripod or firm surface like a table, a wall or a tree to help steady the camera.
The main point with camera movement is to be aware of it and practice those things that work to help you keep steady when you make the exposure.
Shutter speed
Shutter
speed can have a dramatic impact on the appearance of moving objects. Changes
in background blurring are apparent from the need to adjust the aperture size to achieve proper exposure.
The
shutter speed dial of a Nikkormat EL.
Slow
shutter speed combined with panning the camera can achieve a motion blur for
moving objects.
A
photo of sparks coming from coals (exposure time 15 seconds)
A
photo of street at night (exposure time 30 seconds)
.jpg)
An
extended exposure can also allow photographers to catch brief flashes of light,
as seen here. Exposure time 15 seconds.
In photography, shutter speed is the common
term for exposure time, the effective length of time a shutter is
open;[1] the total exposure is
proportional to this exposure time, or duration of light
reaching the film or image sensor.
Introduction
Factors that affect
the total exposure of
a photograph include the scene luminance, the aperture size (f-number), and the exposure time (shutter
speed); photographers can trade off shutter speed and aperture by using units
of stops. A stop up and down on each will halve or double the amount of
light regulated by each; exposures of equal exposure value can be easily calculated and
selected. For any given total exposure, or exposure value, a fast shutter speed
requires a larger aperture (smaller f-number). Similarly, a slow shutter speed, a
longer length of time, can be compensated by a smaller aperture (larger
f-number).Slow shutter speeds are often used in low light conditions, extending the time until the shutter closes, and increasing the amount of light gathered. This basic principle of photography, the exposure, is used in film and digital cameras, the image sensor effectively acting like film when exposed by the shutter.
Shutter speed, or more literally exposure time, is measured in seconds, but often marked in reciprocal seconds. A typical exposure time for photographs taken in sunlight is 1/125th of a second, typically marked as 125 on a shutter speed setting dial. In addition to its effect on exposure, shutter speed changes the way movement appears in the picture. Very short shutter speeds are used to freeze fast-moving subjects, for example at sporting events. Very long shutter speeds are used to intentionally blur a moving subject for artistic effect.[2]
Adjustment to the aperture controls the depth of field, the distance range over which objects are acceptably sharp; such adjustments generally need to be compensated by changes in the shutter speed.
In early days of photography, available shutter speeds were somewhat ad hoc.[1] Following the adoption of a standardized way of representing aperture so that each major step exactly doubled or halved the amount of light entering the camera (f/2.8, f/4, f/5.6, f/8, f/11, f/16, etc.), a standardized 2:1 scale was adopted for shutter speed so that opening one aperture stop and reducing the shutter speed by one step resulted in the identical exposure. The agreed standards for shutter speeds are:[3]
- 1/1000 s
- 1/500 s
- 1/250 s
- 1/125 s
- 1/60 s
- 1/30 s
- 1/15 s
- 1/8 s
- 1/4 s
- 1/2 s
- 1 s
The term "speed" is used in reference to short exposure times as fast, and long exposure times as slow. Shutter speeds are often designated by the reciprocal time, for example 60 for 1/60 s.
Camera shutters often include one or two other settings for making very long exposures:
- B (for bulb)
— keep the shutter open as long as the shutter release is held
- T (for time) — keep the shutter open until the shutter release
is pressed again
An Avro Lancaster over Hamburg — the curved streaking is caused by a
combination of the movement of the photographing aircraft and the long exposure
time required for taking photographs at night.
The ability of the photographer
to take images without noticeable blurring by camera movement is an important
parameter in the choice of slowest possible shutter speed for a handheld
camera. The rough guide used by most 35 mm photographers is that the slowest shutter
speed that can be used easily without much blur due to camera shake is the
shutter speed numerically closest to the lens focal length. For example, for
handheld use of a 35 mm camera with a 50 mm normal lens, the closest shutter speed is 1/60
s. This rule can be augmented with knowledge of the intended application for
the photograph, an image intended for significant enlargement and closeup
viewing would require faster shutter speeds to avoid obvious blur. Through
practice and special techniques such as bracing the camera, arms, or body to
minimize camera movement longer shutter speeds can be used without blur. If a
shutter speed is too slow for hand holding, a camera support — usually a tripod — must
be used. Image stabilization
can often permit the use of shutter speeds 3-4 stops slower (exposures 8-16
times longer).Shutter priority refers to a shooting mode used in semi-automatic cameras. It allows the photographer to choose a shutter speed setting and allow the camera to decide the correct aperture. This is sometimes referred to as Shutter Speed Priority Auto Exposure, or Tv (time value) mode.
Creative utility in
photography
Medium
shutter speed of 1.3 seconds, is enough to cause significant motion blur
Main article: Motion blur
Shutter speed is one
of several methods used to control the amount of light recorded by the camera's
digital sensor or film. It is also used to
manipulate the visual effects of the final image beyond its luminosity.Slower shutter speeds are often selected to suggest movement in a still photograph of a moving subject.
Excessively fast shutter speeds can cause a moving subject to appear unnaturally frozen. For instance, a running person may be caught with both feet in the air with all indication of movement lost in the frozen moment.
When a slower shutter speed is selected, a longer time passes from the moment the shutter opens till the moment it closes. More time is available for movement in the subject to be recorded by the camera.
A slightly slower shutter speed will allow the photographer to introduce an element of blur, either in the subject, where, in our example, the feet, which are the fastest moving element in the frame, might be blurred while the rest remains sharp; or if the camera is panned to follow a moving subject, the background is blurred while the subject remains sharp.
The exact point at which the background or subject will start to blur depends on the rate at which the object is moving, the distance it is from the camera and the focal length of the lens in relation to the size of the digital sensor or film.
When slower shutter speeds, in excess of about half a second, are used on running water, the photo will have a ghostly white appearance reminiscent of fog. This effect can be used in landscape photography.
Zoom burst is a technique which entails the variation of the focal length of a zoom lens during a longer exposure. In the moment that the shutter is opened, the lens is zoomed in, changing the focal length during the exposure. The center of the image remains sharp, while the details away from the center form a radial blur, which causes a strong visual effect, forcing the eye into the center of the image.[4]
Cinematographic shutter
formula
In cinematography, shutter speed is a function of
the frame rate and shutter angle. Most motion picture film cameras
use a rotating shutter
with a shutter angle of 165° or 180°, which leaves the film exposed for about
1/48 or 1/50 second at a standard 24 frame/s.[5]Where E = Exposure, F = Frames per second, and S = Shutter angle:[5]
Shutter Speed Variables
The shutter speed determines how long the shutter is open,
which lets light through the camera to expose the film. Shutter speed is
affected by two variables: aperture and film speed(ASA). When the aperture
is adjusted the amount of light passing through the lens changes. The more
light the faster the shutter speed needed. The ASA is the speed of the film, a
film with a high ASA will expose quickly and a film with a low ASA will expose
slower. With all this data in your camera or by using a meter you can get the
correct exposure on your pictures.A list of the most common shutter speeds:
1/8000 s
1/4000 s
1/2000 s
1/1000 s
1/500 s
1/250 s
1/125 s
1/60 s
1/30 s
1/15 s
1/8 s
1/4 s
1/2 s
1 s
B — keep the shutter open as long as the release lever is engaged.
T — keep the shutter open until the lever is pressed again.
Shutter Speed - Everything You Wanted to Know but
Thought it Was Uncool to Ask
What is shutter speed? Here’s everything you wanted to know (and maybe
more).
Exposure time
The short, and correct, answer is that shutter speed is exposure time. Normally your sensor (or film) sits around in the dark waiting for a bit of action. It is the shutter - like the blinds or curtains which shut light out of your room - which keep the sensor in the dark. When the shutter opens, it lets in light and the sensor gets to work.
Exposure time, then, is the time interval or duration during which your camera’s sensor (or film) is collecting light to capture your image.
Why speed?
Somewhere in the mists of time (anyone help me out
here - the Speed Graphic shutter?) the usage started that equated a short
exposure time or short duration exposure with speed.See: short equals quick equals speedy. A long exposure time was not over quickly, so it equals slow. In the days when all cameras had mechanical shutters that flicked open, then closed again, it was reasonable to think a short exposure time meant the shutters had to move more quickly. In actual fact, all shutters in use now always move at the same speed: they just open for more or less time.
And these days, millions of cameras - e.g. those in cells phones, PDAs - do not have shutters. (How are you going to squeeze them in?) So newbies to digital photography don’t need to feel silly if they are confused by talk about shutter speed. Often there’s no shutter, so how can there be shutter speed, let alone slow and fast speed? Hey, but we really have exposure time.
How do shutters work?
There are three types. Two are essentially blinds
which physically block out light until we call for the exposure.The focal plane type is like two curtains over a window. Each is wide enough to cover the whole window. We start off with one fully drawn = darkness. We pull it across to start the exposure, a bit of window is exposed. Then the second curtain starts to move - keeping pace with the first. The gap between them is narrow for a short exposure, wider with longer exposure. Finally, the first curtain is fully drawn but the second curtain now covers the window: back to darkness. This type is used mainly in dSLR type cameras.
The inter-lens type works like the iris of your eye, except that most of the time the iris is closed shut. For exposure the iris opens, then shuts again. And how long it’s open is the exposure time. It’s that simple.
The sensor type works in a completely different way. It is collecting light all the time - that’s how you can see the image on the screen so you focus and frame up. When you make the exposure, the sensor circuits are told to start collecting light, then the end of the exposure a pulse in the circuits shunts the collected light - now an electrical charge - to under a light-proof cover on the sensor. From there, the charge can be read to create the image.
(It’s tough reading all this, we know. If you ask nicely, we might create some flash movies to show how it all works.)
What do exposure times do?
You, or the camera, selects a combination of
exposure time and lens aperture to make an image that is correctly exposed. But
exposure time does more than that. It is your way to control motion blur.It works this way: when the shutter is open, if there is any movement in your subject, that movement will register as a smear of the image - a streak - on the image. If there’s a lot of movement, the streak will be longer, perhaps long enough to see. If there’s movement but the exposure time is really short, the streak will be there, but it’ll be so short, we won’t think it’s a blur; it will appear sharp (assuming of course the image is in focus).
Exposure time controls blur, in addition to contributing to correct exposure.
Waterfall interlude
Here’s a pictorial interlude.- Look first at the 40
shutter setting: the exposure time is 1/40sec - about quarter the length
of a blink - yet it is too long to capture the fast-moving water, so it is
milky blurred.
- 125 or 1/125sec is a
good average short exposure, but it’s not enough to stop the water. We
need an exposure much much shorter to ‘freeze’ the movement.
- A 2500 setting or
1/2500sec exposure does the trick: we can see individual streams of water
caught sharply.
|
40 (1/40 sec)
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125 (1/125 sec)
|
2500 (1/2500
sec)
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 |
 |
Why the sequence of settings?
Shutter settings are typically numbers in this
kind of sequence: 2000, 1000, 500, 250, 125 - you can see the pattern here:
each is half of the previous. Then it goes 60, 30, 15, 8 - kind of half, or
nearly half each time. 4, 2, 1 … then 2 again?What is going on is that for the actual exposure time, you put a 1 over the number. So, 2000 means 1/2000sec: a very short exposure time - while 1 is 1/1 is 1sec, a long exposure time.
The sequence is because one step to the next gives a doubling or halving of exposure (assuming aperture and sensitivity are held). They aren’t quite doubling or halving because some of the numbers would be awkward to mark on cameras (1/7.5? - given them a break). In fact modern cameras give true halving and doubling steps. Which photographers confusingly call ’stops’: a doubling/halving step is one stop.
What is shutter priority?
In modern auto-exposure (AE) systems, you can let
the camera select both the shutter and aperture settings - this is programmed
mode. In aperture priority AE you can set the lens aperture by hand, and let
the camera figure out the right shutter setting. Or, yup, you worked it by
yourself: in shutter priority AE you set the shutter setting, and the camera
figures out the right aperture setting for the right exposure.
When to use shutter priority?
As we know, shutter settings control motion blur.
So you use shutter priority AE when your priority is control over
motion blur.If you want no blur - maximum sharpness - you set very short exposure times and let the camera figure out a large aperture ( you may need to raise high sensitivity if light’s not too good). I do this when photographing out of moving cars, trains.
If you want blur, set longer exposure times (still on shutter priority) and use a tripod or rely on image stabilization to steady the shot.
- 1/60 - 1/30sec is good
for fast-moving action e.g. in a street festival.
- 1/30 - 1/8 sec is cool
for people walking in crowds, for blurring water in fountains etc. and is
just about hand-holdable.
- 1/4 - 4 sec is a good
start for short streaks of car lights at night.
Fairground send-off
Actually it’s a bit more complicated than I’ve
suggested. As you know, if something is coming straight at you, it may not
appear to be moving that fast (sadly, a cause of many a road accident). But if
it’s going across in front of you, relatively slow movement can look very
rapid. And something that’s far away appears to move more slowly than motion
that’s nearby.So it is with capturing motion blur. Look at these fairground shots.
- As we’d expect, the 500
shutter setting gives nice, sharp images - no motion blur here, my dears!
- With the 60 setting, the
horse is blurred, but the figure behind is less blurred - it is moving
less quickly.
- At the 30 setting, the
horse is very blurred, but some of the poles are not as blurred - they are
further away and coming towards the camera.
- The 8 setting is most
interesting: it is mostly a mush but one pole is amazingly sharp: it must
have been travelling straight at the camera for that fraction of a second.
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500 (1/500 sec)
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60 (1/60 sec)
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30 (1/30 sec)
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8 (1/8 sec)
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