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General Photography
Photography in a Nutshell
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<blockquote data-quote="pedroj" data-source="post: 87228" data-attributes="member: 9297"><p>This is a very simple explanation on photography put together by a friend on mine...It could be helpful in getting your head around photography in general...</p><p></p><p>PHOTOGRAPHY IN A NUT SHELL</p><p>1. A camera is a light proof box with a light sensitive film or electronic chip</p><p>inside it.</p><p>2. The film, or chip, needs a specific amount of light in order to make a</p><p>good quality image. (Each frame requires the same quantity of light in</p><p>order to be correctly exposed).</p><p>3. There are 2 methods of controlling the amount of light that reaches the</p><p>film or chip:</p><p>(a) An adjustable shutter with the following steps on it: B 1 2 4 8</p><p>15 30 60 125 250 500 1000 2000 4000. These represent</p><p>fractions of a second and changing from one step to the next</p><p>fastest will halve the amount of light reaching the film. Changing</p><p>from 1 speed to the next slowest will double the amount of light</p><p>entering the camera. This is known as changing the exposure by 1</p><p>stop. (Digital cameras may have shutter speeds that are adjustable</p><p>in ½ or 1/3 of a stop increments, so the camera may choose to use</p><p>a series of numbers representing these steps in addition to those</p><p>above).</p><p>(b) An adjustable aperture located in the lens. It has the following</p><p>steps, known as F/stops: f2 f2.8 f4 f5.6 f8 f11 f16 f22 f32.</p><p>F2 is the largest opening and f32 is the smallest. Changing from</p><p>one stop to the next will either double or halve the amount of light</p><p>that reaches the film depending on if you are enlarging or reducing</p><p>the aperture . (Digital cameras may alter the f/stop in ½ or 1/3</p><p>stop increments. These will be represented in numbers different to</p><p>those above).</p><p>(c) Depth of field Changing the F stop also alters the depth of</p><p>sharpness in the image. A large f/stop such as f2.8 or f4 will force</p><p>the background of your picture to be out of focus. This might be</p><p>desirable for portraits or pictures of flowers etc. A small f/stop</p><p>such as f11 or f16 will cause the background to become more</p><p>detailed and in focus. This might be important where you wish to</p><p>show as much detail as possible in your image. An interior shot of</p><p>a house, for instance. Be aware that if you desire to use a small</p><p>f/stop then you will drastically reduce the amount of light entering</p><p>the camera and may be forced to use a very slow shutter speed.</p><p>This may force you to use a high ISO film or CCD setting or work</p><p>from a tripod.</p><p>Copyright Matt. Kaarma - 2005</p><p>Copyright D70 Forum</p><p>4. Film or chip sensitivity Some films are very sensitive to light and some</p><p>less so. The sensitivity is indicated by a number on the film box called</p><p>the ISO number (ISO stands for INTERNATIONAL STANDARDS</p><p>ORGANIZATION), and the following ISO films are commonly</p><p>available: 50 100 200 400 800 1600 and 3200. Note the numerical</p><p>pattern. A 400 ISO film is twice as sensitive to light as a 200 ISO film</p><p>and requires only half the brightness of light to make an exposure. A 100</p><p>ISO film is only half as sensitive as a 200 ISO, and requires twice the</p><p>brightness of light to make an exposure. The ISO numbers above</p><p>represent film that is progressively 1 stop more sensitive to light than the</p><p>preceding number. Each higher number increment requires only half the</p><p>amount of light to make a correct exposure.</p><p>5. Low ISO films have less grain and more resolution than high ISO films.</p><p>They produce higher quality imagery but you need more light to take the</p><p>photograph. High ISO films are useful for photography in poor light but</p><p>give a reduced quality.</p><p>6. Digital cameras have an adjustable ISO setting and choosing a high ISO</p><p>will degrade the image quality. This may be a fair trade off if it means the</p><p>difference between getting the image or not getting the image. (Digital</p><p>cameras may have the option of choosing the ISO in ½ or 1/3 f/stop steps</p><p>and these will be indicated by numbers that fit in between the sequence</p><p>shown above).</p><p>7. The art of photography is balancing all of the above elements in order to</p><p>capture an image under a wide range of lighting situations.</p><p>8. The following guidelines will help in ensuring that your imagery is sharp</p><p>and of the highest quality possible under the prevailing lighting</p><p>conditions:</p><p>(a) Use the lowest ISO setting possible in order to satisfy the</p><p>following conditions:</p><p>(b) The shutter speed should be set to match as closely as possible the</p><p>focal length of the lens if the camera is hand held…for instance,</p><p>1/500th of a second if using a 500mm lens. If you are unable to</p><p>achieve this then the camera must be mounted onto a tripod. These</p><p>are minimum shutter speeds and you may and should use any</p><p>higher speed.</p><p>(c) The shutter speed must be set to 1/500th or higher if taking</p><p>photographs from a moving vehicle or aerial platform. (That’s an</p><p>aeroplane or helicopter for those who are earthbound).</p><p>(d) The ISO must be set 1600 ISO for night or very low light level</p><p>photography unless the camera is mounted onto a tripod.</p><p>Copyright Matt. Kaarma - 2005</p><p>Copyright D70 Forum</p><p>(e) The aperture must be set to small f/stops if you require an</p><p>extended depth of field…(f/11, f/16, f/22 etc). This will reduce the</p><p>amount of light entering the camera and force you to use slower</p><p>shutter speeds…(1/8th, 1/15th, 1/30th etc).</p><p>(f) If you are photographing a moving subject then the shutter speed</p><p>must be increased as the subject’s speed increases. Useful</p><p>guidelines are, (assuming focal length = shutter speed rule has</p><p>been applied):</p><p>Man walking…1/125</p><p>Man running…1/250</p><p>Moving motorbike…1/500</p><p>Speeding motorbike...1/1000</p><p>7. You can check the accuracy of your camera’s lightmeter by setting the</p><p>ISO to 200, the shutter speed to 1/250 and the f/stop to f11. On a bright</p><p>sunny day, with the sun directly above or behind you, the lightmeter</p><p>should indicate correct exposure when aimed at green grass or a</p><p>KODAK Grey card. If the camera indicates f/16 or f/11 then this is</p><p>acceptable. Any other reading indicates that the lightmeter is probably</p><p>faulty.</p><p>8. Do not use long focal length lenses if shooting from a moving platform</p><p>such as a car, boat or aircraft. Use the highest shutter speed possible for</p><p>sharp imagery. (It is better to use high ISO values and pick up a little</p><p>loss of imagery quality than to capture blurred and useless imagery).</p><p>9. In the following scenario the camera has automatically set f/8 and 1/250</p><p>of a second as the correct exposure: If you now manually set the f/stop</p><p>to f/11 you have halved the amount of light entering the camera by 1</p><p>stop. The image will be a little too dark. However….if you now</p><p>manually set the shutter speed to 1/125 of a second you have doubled the</p><p>amount of light entering the camera and the light meter will once again</p><p>indicate correct exposure. Therefore f/8 @ 1/250 allows the same</p><p>amount of light to enter the camera as f/11 @ 1/125. Both of these</p><p>settings have the same exposure value. (Often referred to as EV). In the</p><p>above scenario we could also set f/16 @ 1/60 and f/22 @ 1/30 or f/5.6</p><p>@ 1/500. The lesson here is that when the cameras meter indicates a</p><p>combination of shutter speed and f/stop….then you are not locked into</p><p>using that particular combination. You have options and the kind of</p><p>subject you are photographing and the amount of light that is available</p><p>will affect your decision to choose one combination over another.</p><p>Copyright Matt. Kaarma - 2005</p><p>Copyright D70 Forum</p></blockquote><p></p>
[QUOTE="pedroj, post: 87228, member: 9297"] This is a very simple explanation on photography put together by a friend on mine...It could be helpful in getting your head around photography in general... PHOTOGRAPHY IN A NUT SHELL 1. A camera is a light proof box with a light sensitive film or electronic chip inside it. 2. The film, or chip, needs a specific amount of light in order to make a good quality image. (Each frame requires the same quantity of light in order to be correctly exposed). 3. There are 2 methods of controlling the amount of light that reaches the film or chip: (a) An adjustable shutter with the following steps on it: B 1 2 4 8 15 30 60 125 250 500 1000 2000 4000. These represent fractions of a second and changing from one step to the next fastest will halve the amount of light reaching the film. Changing from 1 speed to the next slowest will double the amount of light entering the camera. This is known as changing the exposure by 1 stop. (Digital cameras may have shutter speeds that are adjustable in ½ or 1/3 of a stop increments, so the camera may choose to use a series of numbers representing these steps in addition to those above). (b) An adjustable aperture located in the lens. It has the following steps, known as F/stops: f2 f2.8 f4 f5.6 f8 f11 f16 f22 f32. F2 is the largest opening and f32 is the smallest. Changing from one stop to the next will either double or halve the amount of light that reaches the film depending on if you are enlarging or reducing the aperture . (Digital cameras may alter the f/stop in ½ or 1/3 stop increments. These will be represented in numbers different to those above). (c) Depth of field Changing the F stop also alters the depth of sharpness in the image. A large f/stop such as f2.8 or f4 will force the background of your picture to be out of focus. This might be desirable for portraits or pictures of flowers etc. A small f/stop such as f11 or f16 will cause the background to become more detailed and in focus. This might be important where you wish to show as much detail as possible in your image. An interior shot of a house, for instance. Be aware that if you desire to use a small f/stop then you will drastically reduce the amount of light entering the camera and may be forced to use a very slow shutter speed. This may force you to use a high ISO film or CCD setting or work from a tripod. Copyright Matt. Kaarma - 2005 Copyright D70 Forum 4. Film or chip sensitivity Some films are very sensitive to light and some less so. The sensitivity is indicated by a number on the film box called the ISO number (ISO stands for INTERNATIONAL STANDARDS ORGANIZATION), and the following ISO films are commonly available: 50 100 200 400 800 1600 and 3200. Note the numerical pattern. A 400 ISO film is twice as sensitive to light as a 200 ISO film and requires only half the brightness of light to make an exposure. A 100 ISO film is only half as sensitive as a 200 ISO, and requires twice the brightness of light to make an exposure. The ISO numbers above represent film that is progressively 1 stop more sensitive to light than the preceding number. Each higher number increment requires only half the amount of light to make a correct exposure. 5. Low ISO films have less grain and more resolution than high ISO films. They produce higher quality imagery but you need more light to take the photograph. High ISO films are useful for photography in poor light but give a reduced quality. 6. Digital cameras have an adjustable ISO setting and choosing a high ISO will degrade the image quality. This may be a fair trade off if it means the difference between getting the image or not getting the image. (Digital cameras may have the option of choosing the ISO in ½ or 1/3 f/stop steps and these will be indicated by numbers that fit in between the sequence shown above). 7. The art of photography is balancing all of the above elements in order to capture an image under a wide range of lighting situations. 8. The following guidelines will help in ensuring that your imagery is sharp and of the highest quality possible under the prevailing lighting conditions: (a) Use the lowest ISO setting possible in order to satisfy the following conditions: (b) The shutter speed should be set to match as closely as possible the focal length of the lens if the camera is hand held…for instance, 1/500th of a second if using a 500mm lens. If you are unable to achieve this then the camera must be mounted onto a tripod. These are minimum shutter speeds and you may and should use any higher speed. (c) The shutter speed must be set to 1/500th or higher if taking photographs from a moving vehicle or aerial platform. (That’s an aeroplane or helicopter for those who are earthbound). (d) The ISO must be set 1600 ISO for night or very low light level photography unless the camera is mounted onto a tripod. Copyright Matt. Kaarma - 2005 Copyright D70 Forum (e) The aperture must be set to small f/stops if you require an extended depth of field…(f/11, f/16, f/22 etc). This will reduce the amount of light entering the camera and force you to use slower shutter speeds…(1/8th, 1/15th, 1/30th etc). (f) If you are photographing a moving subject then the shutter speed must be increased as the subject’s speed increases. Useful guidelines are, (assuming focal length = shutter speed rule has been applied): Man walking…1/125 Man running…1/250 Moving motorbike…1/500 Speeding motorbike...1/1000 7. You can check the accuracy of your camera’s lightmeter by setting the ISO to 200, the shutter speed to 1/250 and the f/stop to f11. On a bright sunny day, with the sun directly above or behind you, the lightmeter should indicate correct exposure when aimed at green grass or a KODAK Grey card. If the camera indicates f/16 or f/11 then this is acceptable. Any other reading indicates that the lightmeter is probably faulty. 8. Do not use long focal length lenses if shooting from a moving platform such as a car, boat or aircraft. Use the highest shutter speed possible for sharp imagery. (It is better to use high ISO values and pick up a little loss of imagery quality than to capture blurred and useless imagery). 9. In the following scenario the camera has automatically set f/8 and 1/250 of a second as the correct exposure: If you now manually set the f/stop to f/11 you have halved the amount of light entering the camera by 1 stop. The image will be a little too dark. However….if you now manually set the shutter speed to 1/125 of a second you have doubled the amount of light entering the camera and the light meter will once again indicate correct exposure. Therefore f/8 @ 1/250 allows the same amount of light to enter the camera as f/11 @ 1/125. Both of these settings have the same exposure value. (Often referred to as EV). In the above scenario we could also set f/16 @ 1/60 and f/22 @ 1/30 or f/5.6 @ 1/500. The lesson here is that when the cameras meter indicates a combination of shutter speed and f/stop….then you are not locked into using that particular combination. You have options and the kind of subject you are photographing and the amount of light that is available will affect your decision to choose one combination over another. Copyright Matt. Kaarma - 2005 Copyright D70 Forum [/QUOTE]
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