#2 shutter speed

Shutter speed is shown in fraction form. The fraction is referring to the 1/15 of a second (slow) that it takes the shutter to open and close. Or the 1/6000 of a second (fast) it takes to open and close.

A slow shutter speed allows more light to come in because the shutter is open longer. But since the shutter is opened longer it also allows for some movement in your picture (motion blur) if it’s open longer than 1/80 of a second and there is a moving object/child in front of the camera.

Many photographers over estimate how steady they can hold a camera. Using a standard 50mm lens the minimum shutter speed you should use will be ‘one over 50′, which is 1/50. To turn it into a shutter speed you simply call it a fraction of a second, like this; 1/50th of a second. The nearest shutter speed you can set is actually 1/60th of a second but you get the idea. So if you’re shooting at 200mm the minimum shutter speed you should use will be ‘one over 200′, which is 1/200th of a second. So you would set your shutter speed to 1/250th of a second, that being the closest to 1/200. These figures are just a rough guide and may vary according to individual ability. Over time you will learn how slow a shutter speed you can hand hold but if in doubt always err on the fast side. It wouldn’t generally recommend you hand hold any camera/lens combination below 1/30th of a second.

The image below was shot with a shutter speed of 1/4 second (f20, ISO 100) using a neutral density filter. To get this effect on a very sunny June day was not easy. I had my son Theo stand still while his friends ran around him. The camera was on a tripod because of the slow shutter speed needed and I had screw-in neutral density filter +8 filter otherwise the image would have been completely over exposed as there would have been too much light hitting the sensor. There’s a great article on ND Filter’s here.

For most people the most important aspect of choosing a shutter speed is getting one fast enough to freeze movement. Unfortunately the world is full of things that all move at different speeds and no one bothered to make a list of what shutter speed would be needed to freeze each and every one of them. With this in mind I have put together a little table containing some common ‘things that move’ and a suitable shutter speed to stop them. You can use these values as a basis for working out shutter speeds for other situations you may encounter. This is a rough guide only so don’t sue me if one doesn’t work for you – try increasing another stop.

 

rujukan : Foto Friday

Introduction to Shutter Speed in Digital Photography

Previously I’ve introduced the concept of the Exposure Triangle as a way of thinking about getting out of Auto Mode and exploring the idea of manually adjusting the exposure of your shots.

Photo by Hughes500

The three main areas that you can adjust are ISO, Aperture and Shutter speed. I’ve previously looked at making adjustments to ISO and now want to turn our attention to shutter speed.

What is Shutter Speed?
As I’ve written elsewhere, defined most basically – shutter speed is ‘the amount of time that the shutter is open’.

In film photography it was the length of time that the film was exposed to the scene you’re photographing and similarly in digital photography shutter speed is the length of time that your image sensor ‘sees’ the scene you’re attempting to capture.
Let me attempt to break down the topic of “Shutter Speed” into some bite sized pieces that should help digital camera owners trying to get their head around shutter speed:

Photo by konaboy

• Shutter speed is measured in seconds – or in most cases fractions of seconds. The bigger the denominator the faster the speed (ie 1/1000 is much faster than 1/30).
• In most cases you’ll probably be using shutter speeds of 1/60th of a second or faster. This is because anything slower than this is very difficult to use without getting camera shake. Camera shake is when your camera is moving while the shutter is open and results in blur in your photos.
• If you’re using a slow shutter speed (anything slower than 1/60) you will need to either use a tripod or some some type of image stabilization (more and more cameras are coming with this built in).
• Shutter speeds available to you on your camera will usually double (approximately) with each setting. As a result you’ll usually have the options for the following shutter speeds – 1/500, 1/250, 1/125, 1/60, 1/30, 1/15, 1/8 etc. This ‘doubling’ is handy to keep in mind as aperture settings also double the amount of light that is let in – as a result increasing shutter speed by one stop and decreasing aperture by one stop should give you similar exposure levels (but we’ll talk more about this in a future post).
• Some cameras also give you the option for very slow shutter speeds that are not fractions of seconds but are measured in seconds (for example 1 second, 10 seconds, 30 seconds etc). These are used in very low light situations, when you’re going after special effects and/or when you’re trying to capture a lot of movement in a shot). Some cameras also give you the option to shoot in ‘B’ (or ‘Bulb’) mode. Bulb mode lets you keep the shutter open for as long as you hold it down.
• When considering what shutter speed to use in an image you should always ask yourself whether anything in your scene is moving and how you’d like to capture that movement. If there is movement in your scene you have the choice of either freezing the movement (so it looks still) or letting the moving object intentionally blur (giving it a sense of movement).
• To freeze movement in an image (like in the surfing shot above) you’ll want to choose a faster shutter speed and to let the movement blur you’ll want to choose a slower shutter speed. The actual speeds you should choose will vary depending upon the speed of the subject in your shot and how much you want it to be blurred.
• Motion is not always bad – I spoke to one digital camera owner last week who told me that he always used fast shutter speeds and couldn’t understand why anyone would want motion in their images. There are times when motion is good. For example when you’re taking a photo of a waterfall and want to show how fast the water is flowing, or when you’re taking a shot of a racing car and want to give it a feeling of speed, or when you’re taking a shot of a star scape and want to show how the stars move over a longer period of time etc. In all of these instances choosing a longer shutter speed will be the way to go. However in all of these cases you need to use a tripod or you’ll run the risk of ruining the shots by adding camera movement (a different type of blur than motion blur).
• Focal Length and Shutter Speed - another thing to consider when choosing shutter speed is the focal length of the lens you’re using. Longer focal lengths will accentuate the amount of camera shake you have and so you’ll need to choose a faster shutter speed (unless you have image stabilization in your lens or camera). The ‘rule’ of thumb to use with focal length in non image stabilized situations) is to choose a shutter speed with a denominator that is larger than the focal length of the lens. For example if you have a lens that is 50mm 1/60th is probably ok but if you have a 200mm lens you’ll probably want to shoot at around 1/250.

Photo by flamed

Shutter Speed – Bringing it Together

Remember that thinking about Shutter Speed in isolation from the other two elements of the Exposure Triangle (aperture and ISO) is not really a good idea. As you change shutter speed you’ll need to change one or both of the other elements to compensate for it.

For example if you speed up your shutter speed one stop (for example from 1/125th to 1/250th) you’re effectively letting half as much light into your camera. To compensate for this you’ll probably need to increase your aperture one stop (for example from f16 to f11). The other alternative would be to choose a faster ISO rating (you might want to move from ISO 100 to ISO 400 for example).

I’ll write more on bringing it together once I’ve written a post in the coming week on the last element of the Exposure Triangle – Aperture.

copyright from : dPS

Controlling Depth of Field

The majority of people who take photographs do not understand the importance of depth of field. By definition, depth of field is the focal area that is acceptably sharp in each photograph. This distance of what is sharp could range from a fraction of an inch to hundreds of feet. There are four important factors that control the area of sharpness. They are the focusing setting, aperture size, focal length, and distance of the subject to the camera. Many imagine that they would want everything in the picture to be equally sharp throughout the entire picture. While this is true for many landscape pictures, many other types of photography are actually more visually pleasing with a narrow area of focal sharpness. By making only a select portion of a picture sharp our eye naturally knows what is being emphasized.

Narrow Depth of Field

Wide Depth of Field

Focusing Setting

The optics involved with focusing is a fascinating study all by itself, but when dealing with depth of field, the setting of the lens’ focal point is critical. The focal point is the exact distance set on the lens. Whatever the focal point is set at will always be the sharpest portion in the scene. The average focusing distance usually ranges between several feet to infinity. Most SLR lenses show the distance in feet or meters on the side of the lens. From the initial focal point, one third of the range in front and two thirds of the range in the back of the scene will be the depth of field. For example, if we set our lens to focus at 10 feet the acceptably sharp range could be 5 feet to 20 feet. The total distance range of what is sharp is determined by several other factors that are listed below. 

Aperture Size 

The aperture works the same way as the human iris regulating the amount of light that reaches the image recording sensor or film. The term f-stop represents the size of the aperture opening. As the f-stop number becomes larger, the size of the aperture becomes smaller. As the aperture becomes smaller, the amount of depth of field increases in the photograph. For example, a photograph at f/4 will have a narrow depth of field (sharper focusing) than a photograph at f/16. 

Focal Length

The focal length is the physical length of the lens to the focal plane (sensor or film back of the camera). A larger focal length will make the subject larger in the frame. If you stand at the same location and zoom in (use a bigger millimeter number), the picture will have less depth of field than if you zoomed out (use a smaller millimeter number).

Distance of the Subject

If you use the same focal length and aperture size and only change the distance of the subject and focusing, the amount of depth of field will also be different. As the distance to the subject becomes closer, the depth of field becomes narrower. This factor becomes extremely critical when doing macro photography. Most close-up and macro photography can have less than an inch of focus range that is completely sharp. The reverse is also true. When photographing landscape photographs, the vast distance allows for much more depth of field.

Panning and Zooming Techniques

 The three camera settings that control the exposure are the aperture, ISO, and the shutter speed. If one of these setting changes, one of the other two settings must change to have an equivalent exposure. For example, if we have an exposure of f/5.6, 1/60, and ISO 100 and change the f-stop to 4.0, we must change the shutter speed or the ISO speed by one stop darker. Our new equivalent exposure could be f/5.6, 1/60, and ISO 50 or f/5.6, 1/125, and ISO 100. As any experienced photographer knows, all of photography is a compromise in one way or another. Learning what camera setting to change for the best quality picture can be a challenging task. Once you begin to master the concepts of exposure vs quality, you should try to be creative with your photography technique. These techniques will help you to keep your photographic juices flowing.

Panning Technique

Shutter 1/30, Panning at Full Sprint

 The panning technique uses a slow shutter speed combined with continually panning from left to right or right to left. The correct shutter speed to use varies by the subject matter. To blur a NASCAR stock car can take shutter speeds up to 1/250, a pedal biker can take shutter speeds around 1/60, and a person running can take a shutter speed of around 1/30. For the best results you should follow the subject with the camera before pressing the shutter button. The goal is to maintain the subject in the same portion of the frame throughout the entire pan. After pressing the shutter, you should continue to follow your subject in the frame of the camera. The results create a relatively sharp subject with a motion blurred background and foreground. 

Zooming Technique

Shutter 1/30, Zooming from 28mm - 180mm

  This technique is limited to cameras with zoom lenses that have manual zoom rings. The zooming technique is similar to the panning technique because it requires a slower shutter speed. Instead of panning while pressing the shutter, you quickly zoom in or out during the exposure. The shutter speeds can vary anywhere between ½ - 1/30 of a second. Because the center of the lens always remains the same, the center portion of the picture will look relatively sharp while the rest of the picture will have streaking lines that appear to be coming forward in the scene.

     While both techniques can be closely mimicked in editing programs like Adobe Photoshop, I believe you will find it more rewarding to experiment without the need for post-production editing. A great panning or zooming technique may take lots of practice but the results are always a thrilling success.

Shutter 1/30, Panning Technique

copyright from : Milky Way Photography