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© Copyright 2017, Digital Photography Beginners. All rights reserved.

Understanding ISO and how use it as part of

your exposure

There are three distinct functions on the camera that make a difference to

the exposure – Aperture, Shutter speed and ISO.

There are three distinct functions on the camera that make a difference to the exposure – Aperture, Shutter speed and ISO. These 3 functions were all designed to use the same rule when their scales were calibrated – moving a stop up or down any scale will double or half the light exposure of the photograph. If you were to take a picture using the same sized aperture throughout, something that took 1 second to be photographed at ISO 100 would only take ½ second at ISO 200 because ISO 200 is twice as fast. If you then used ISO 400, it would be twice as fast again, so it would only take ¼ second to photograph. The ability to interchange values off one scale for another gives an incredible flexibility in the exposure of your photographs, and you can start to take more control over the way you capture your pictures in camera. Why set the ISO yourself? After all, isn’t that what the camera’s paid for?  While it’s true that the automatic camera setting does the job, sometimes it will choose an ISO slightly higher than is necessary, in order to give a slightly quicker shutter speed. By choosing your own ISO, and starting to control exposure settings yourself, you can begin to control the quality and look of your final photograph. How to Adjust Your Camera Controls To Suit Conditions Our eyes are fantastic. They are so good at adjusting to, and coping with, a wide range of light levels, that we don’t always appreciate the restricted way that the camera sees. Take dusk. Our eyes are constantly adjusting to the change in light. They do it so well that we don’t register just how dark it is, but for a camera, there simply isn’t enough light to take a picture at a high enough shutter speed to avoid things like camera shake or motion blur, both of which give an out of focus picture that lacks detail and definition, or the picture is just too dark. If it is not possible to change the aperture, one way to help the camera is to change the ISO setting.  By setting a higher ISO, you are adjusting the camera’s sensitivity to light to help the camera be able to take a better picture. Turning the ISO up can also help do away with the need to use the built in flash. A faster ISO will let you use a quicker shutter speed and let you take more subtle and unobserved photographs. The way the sensor increases the ISO is the major downside. While the higher ISO values react to light faster, you start to introduce more ‘noise’ into your pictures. Noise is the little specks of colour that appear in a photograph, especially in the shadow detail, where the colour appear in clumps of colours. This color noise gives a distinct mottling effect when printed out, but that is the compromise you make. You sacrifice some image quality to be able to take the photograph more easily. There will be times when you are out and about and you come across a lovely evening scene that you want to photograph. If you wish to minimize the amount of noise present in a night photograph, keep the ISO down to 100-400 and by putting the camera on a tripod, you can get a nice crisp, relatively noise-free image. But what if it is one of the many times you aren’t carrying a tripod with you? There is almost always something to hand that you can rest your camera on, a solid surface such as a wall or ledge is ideal, but just by supporting your hands and camera on a fence or tree branch, you can minimize the camera shake and still take a relatively long exposure at a low ISO. This shot above was captured at ISO 200 without a tripod, by using a metal fence post to rest the camera on, so that there was no camera shake even with a shutter speed of ½ second. But you may want to introduce noise at some point to add mood or give a film grain effect to some of your black and white shots. Here, converting a foggy night shot taken with ISO set to 1600 had converted the noise pattern into a grainy look which gives the final black and white image a moody slightly sinister feel. Manipulating Aperture, Shutter speed and ISO For Effect Once you understand the relationship between Aperture, Shutter speed and ISO, you can start to explore a range of effects that can add new dimension and depth to your images. Here is a few ways you can do this. Movement is shown in photographs by a degree of blur shown in an area of the picture. You have probably experienced camera shake at one time or another, which blurs the whole of your photograph and is caused because the camera was moved as the picture was taken. Although caused by movement it is not a good effect because it destroys the image and makes people’s faces unrecognizable. To capture movement in a picture, only the object that is moving should be blurred and that means using a shutter speed long enough to show the subject moving. By keeping the ISO low, (and/or the aperture small), you can force the camera to use a longer shutter speed, letting you deliberately capture movement and motion. A low ISO in this shaded spot has allowed an extended shutter speed of 1/10th. This, in turn, has given the water a misty, soft appearance. Longer shutter speed times can show speed or movement off to great effect. But what if there is too much light around to be able to get the pictures you want? For example, a very sunny day at the beach or in a sunlit building with white walls.  We know that too much light will over expose a photograph. It makes everything become ghostly and washed out. Reducing the ISO setting makes the camera’s sensor less responsive to light, so the camera is able to cope better with this abundance of light. Consequently, it will be able to take a better exposed image. Another reason you may want to manipulate your exposure settings is to control how much of your picture is in focus at any one time. You can do this using the Aperture. Depth of field (DoF) starts with the point in your picture that you focus on. With every aperture size, there is a certain distance in front and behind the point that you focus on that will also be in focus. There is always more in focus behind the subject than there is in front (as you can see in the diagram above). The smaller the size of Aperture you use, the larger the depth of field gets. So by using a smaller Aperture, more of your picture will be in focus. You can use a shallow DoF to isolate your subject from the background, making the background blurred (out of focus) by using a large aperture. By making the Aperture progressively smaller, more of the subject comes into sharper focus. Using a really small Aperture gives a depth of field which will allow the whole subject to be in focus from front to back. Depth of Field varies with how close your subject is to the camera, what lens you are using and with how much zoom or magnification you are using, but by playing around, you will begin to grasp the effect Aperture has on DOF. What if you want to photograph something really fast? Well being able to select a fast Shutter speed is a really good advantage. Subjects like the following need a quick Shutter speed to freeze the action: Sports Moving Transport   Active Children Water   Having the flexibility to alter all three exposure elements of Shutter speed, ISO and Aperture helps you tailor your exposure both to the shooting conditions AND to suit your creative desires. So next time your camera doesn’t quite give you the exposure for the photograph you want to take, don’t be afraid to give it a helping hand. Use the relationship between Aperture, ISO and Shutter speed to take back control over your pictures and get what you ACTUALLY want. After you’ve put all this work in, you want to look at your printed photos and see an improvement in the quality of the finished image. What if your pictures look great on screen but print out badly. Why could that happen? Could it have something to do with the size of your picture?
Digital Photography Beginners
© Copyright 2017, Digital Photography Beginners. All rights reserved.

Understanding ISO

and how use it as

part of your

exposure

There are three distinct

functions on the camera that

make a difference to the

exposure – Aperture, Shutter

speed and ISO.

There are three distinct functions on the camera that make a difference to the exposure – Aperture, Shutter speed and ISO. These 3 functions were all designed to use the same rule when their scales were calibrated – moving a stop up or down any scale will double or half the light exposure of the photograph. If you were to take a picture using the same sized aperture throughout, something that took 1 second to be photographed at ISO 100 would only take ½ second at ISO 200 because ISO 200 is twice as fast. If you then used ISO 400, it would be twice as fast again, so it would only take ¼ second to photograph. The ability to interchange values off one scale for another gives an incredible flexibility in the exposure of your photographs, and you can start to take more control over the way you capture your pictures in camera. Why set the ISO yourself? After all, isn’t that what the camera’s paid for?  While it’s true that the automatic camera setting does the job, sometimes it will choose an ISO slightly higher than is necessary, in order to give a slightly quicker shutter speed. By choosing your own ISO, and starting to control exposure settings yourself, you can begin to control the quality and look of your final photograph. How to Adjust Your Camera Controls To Suit Conditions Our eyes are fantastic. They are so good at adjusting to, and coping with, a wide range of light levels, that we don’t always appreciate the restricted way that the camera sees. Take dusk. Our eyes are constantly adjusting to the change in light. They do it so well that we don’t register just how dark it is, but for a camera, there simply isn’t enough light to take a picture at a high enough shutter speed to avoid things like camera shake or motion blur, both of which give an out of focus picture that lacks detail and definition, or the picture is just too dark. If it is not possible to change the aperture, one way to help the camera is to change the ISO setting.  By setting a higher ISO, you are adjusting the camera’s sensitivity to light to help the camera be able to take a better picture. Turning the ISO up can also help do away with the need to use the built in flash. A faster ISO will let you use a quicker shutter speed and let you take more subtle and unobserved photographs. The way the sensor increases the ISO is the major downside. While the higher ISO values react to light faster, you start to introduce more ‘noise’ into your pictures. Noise is the little specks of colour that appear in a photograph, especially in the shadow detail, where the colour appear in clumps of colours. This color noise gives a distinct mottling effect when printed out, but that is the compromise you make. You sacrifice some image quality to be able to take the photograph more easily. There will be times when you are out and about and you come across a lovely evening scene that you want to photograph. If you wish to minimize the amount of noise present in a night photograph, keep the ISO down to 100-400 and by putting the camera on a tripod, you can get a nice crisp, relatively noise- free image. But what if it is one of the many times you aren’t carrying a tripod with you? There is almost always something to hand that you can rest your camera on, a solid surface such as a wall or ledge is ideal, but just by supporting your hands and camera on a fence or tree branch, you can minimize the camera shake and still take a relatively long exposure at a low ISO. This shot above was captured at ISO 200 without a tripod, by using a metal fence post to rest the camera on, so that there was no camera shake even with a shutter speed of ½ second. But you may want to introduce noise at some point to add mood or give a film grain effect to some of your black and white shots. Here, converting a foggy night shot taken with ISO set to 1600 had converted the noise pattern into a grainy look which gives the final black and white image a moody slightly sinister feel. Manipulating Aperture, Shutter speed and ISO For Effect Once you understand the relationship between Aperture, Shutter speed and ISO, you can start to explore a range of effects that can add new dimension and depth to your images. Here is a few ways you can do this. Movement is shown in photographs by a degree of blur shown in an area of the picture. You have probably experienced camera shake at one time or another, which blurs the whole of your photograph and is caused because the camera was moved as the picture was taken. Although caused by movement it is not a good effect because it destroys the image and makes people’s faces unrecognizable. To capture movement in a picture, only the object that is moving should be blurred and that means using a shutterspeed long enough to show the subject moving. By keeping the ISO low, (and/or the aperture small), you can force the camera to use a longer shutter speed, letting you deliberately capture movement and motion. A low ISO in this shaded spot has allowed an extended shutter speed of 1/10th. This, in turn, has given the water a misty, soft appearance. Longer shutter speed times can show speed or movement off to great effect. But what if there is too much light around to be able to get the pictures you want? For example, a very sunny day at the beach or in a sunlit building with white walls.  We know that too much light will over expose a photograph. It makes everything become ghostly and washed out. Reducing the ISO setting makes the camera’s sensor less responsive to light, so the camera is able to cope better with this abundance of light. Consequently, it will be able to take a better exposed image. Another reason you may want to manipulate your exposure settings is to control how much of your picture is in focus at any one time. You can do this using the Aperture. Depth of field (DoF) starts with the point in your picture that you focus on. With every aperture size, there is a certain distance in front and behind the point that you focus on that will also be in focus. There is always more in focus behind the subject than there is in front (as you can see in the diagram above). The smaller the size of Aperture you use, the larger the depth of field gets. So by using a smaller Aperture, more of your picture will be in focus. You can use a shallow DoF to isolate your subject from the background, making the background blurred (out of focus) by using a large aperture. By making the Aperture progressively smaller, more of the subject comes into sharper focus. Using a really small Aperture gives a depth of field which will allow the whole subject to be in focus from front to back. Depth of Field varies with how close your subject is to the camera, what lens you are using and with how much zoom or magnification you are using, but by playing around, you will begin to grasp the effect Aperture has on DOF. What if you want to photograph something really fast? Well being able to select a fast Shutter speed is a really good advantage. Subjects like the following need a quick Shutter speed to freeze the action: Sports Moving Transport   Active Children Water   Having the flexibility to alter all three exposure elements of Shutter speed, ISO and Aperture helps you tailor your exposure both to the shooting conditions AND to suit your creative desires. So next time your camera doesn’t quite give you the exposure for the photograph you want to take, don’t be afraid to give it a helping hand. Use the relationship between Aperture, ISO and Shutter speed to take back control over your pictures and get what you ACTUALLY want. After you’ve put all this work in, you want to look at your printed photos and see an improvement in the quality of the finished image. What if your pictures look great on screen but print out badly. Why could that happen? Could it have something to do with the size of your picture?
Digital Photography Beginners