Digital Photography
Explain how to use the exposure compensation control.
A feature in your camera that allows you to adjust exposure without having to adjust shutter speeds and apertures.
List the basic parts to a DSLR camera.
1. Body - The light tight box 2. Lens - Focuses the image in the viewfinder and on the sensor. 3. Lens elements - The optical glass lens components that produce the image 4. Focusing ring - Turning the ring focuses the image by adjusting the distance of the lens from the sensor. 5. Diaphragm - A circle of overlapping leaves inside the lens that adjust the size of the aperture. 6. Aperture ring or button - Turning a command dial controls the size of the aperture. 7. Mirror - The mirror reflects light from the lens upward onto the viewing screen. During an exposure, the mirror swings out of the way so light can pass straight through to the sensor. 8. Viewing screen - Ground glass surface on which the focused image appears. 9. Pentaprism - A five sided optical device that reflects the image from the viewing screen into the viewfinder. 10. Metering cell - Measures the brightness of the scene being photographed. 11. Viewfinder eyepiece - A window through which the image from the pentaprism is visible. 12. Shutter - Pressing the shutter release opens the and closes the shutter to let in a measured amount of light to reach the sensor. 13. Sensor - A CCD or CMOS chip comprising of millions of light sensitive cells called pixels. Each pixel has a photosite that record the image. 14. Data panel - A display the shows exposure information, ISO, White balance settings, and the number of exposures left on the memory card. 15. Command dial - Selects the shutter speed. 16. Hot Shoe - Attaches an external flash unit to your camera. 17. Mode dial - Allows you to select exposure modes. 18. Cable connections - Plug-ins for usb, audio, external power, and monitor. 19. Memory card - Stores image files. May be erased and reused. Capacity varies.
What are the two most common image sensors?
1. CCD (Charge Coupled Device) 2. CMOS (Complementary Metal Oxide Semiconductor)
What are the different types of digital cameras?
1.) Compact cameras are designed for amateur photographers but vary considerably in quality. The smaller the camera, the more likely the features will be limited. 2.) Subcompact cameras can be carried in a pocket so you are ready to make picture anywhere, any time, but image quality and features often compare poorly to larger cameras. Few compacts allow manual control. 3.) DSLRs (single-lens reflex) are the most versatile choice. They accept interchangeable lenses and are full featured. They are big enough you will only carry one when you mean to use it.
What are the characteristics of a normal focal length?
A normal focal length lens produces an image that has the same angle of view and magnification as the human eye. The normal lens for full frame camera is 50mm. The normal lens for a reduced sensor camera is approximately 28mm The size of the sensor determines what focal length is normal. A normal lens has a focal length approximately equal to the diagonal of the sensor. Advantages • Normal lenses are generally faster. Which means they have a wider maximum apertures, which makes them convenient for use in dim light. • They are a good choice if the camera is going to be hand held because the maximum aperture permits a shutter speed fast enough to prevent blur by camera movement. • They are compact and lighter. • They are somewhat less expensive.
What are the characteristics of prime, zoom, macro, and fisheye lenses?
A prime lens. has a single or fixed focal length. (35mm, 50mm, 105mm etc.) A zoom lens has a variable or adjustable focal length. (18 to 55mm, 70 to 300mm etc.) Macro lenses are used for close-up photography. Their optical design corrects for the lens aberrations that cause problems at very short focusing distances but they can be used at normal distances. Fisheye lenses - have a very wide angle of view—up to 180º—and they exaggerate to an extreme degree of differences in the size between objects that are to close to the camera and those that are farther away. They distort the image by bending straight lines at the edges of the picture.
. What are the characteristics of a short focal length?
A short focal length lens (wide angle lens) will have a wider angle of view and will decrease magnification. A 35mm wide angle lens records a 63º angle of view and a 7.5mm fisheye lens records a 180º angle of view. A popular wide angle lens for a full frame camera is 28mm—for a reduced size sensor it would be 18mm. A short lens can give you great depth of field.
Explain auto white balance and white balance presets.
All cameras are going to have and automatic white balance feature and depending on the quality of your camera, this might be all that you need to use to get accurate white balance. The simplest white balance look for the brightest point in your shot, assume that it is white, and then uses that point as a reference to balance. More sophisticated automatic white balancers perform a complex analysis of many different areas in your image. Both are surprisingly effective, and you will almost always get good color when shooting in direct sunlight, and decent color in other lighting conditions. However, even a few clouds can confuse an auto white balance mechanism, and in other types of light. You may find out that your auto white balance works very poorly. So even with the best cameras, you will very often need to switch out of auto white balance mode. Fortunately, there are white balance presets for different lighting conditions. • Daylight • Tungsten • Fluorescent • Cloudy • Flash These white balance presets are usually more accurate than automatic white balance in the situations for which they were designed. Some cameras will specify a white balance preset in degrees Kelvin. Be sure you understand which setting corresponds to which type of light.
Describe the effects of under and overexposure?
An underexposed image will be too dark An overexposed image will be too light.
What are the characteristics of a long focal length?
As focal length gets longer the angle of view narrows and the magnification increases. This is useful when you can't or you don't want to get closer to the subject. Such as sports or nature photography As the focal length increase, the depth of field decreases so that less of the scene is in focus at a given f-stop. When focused at the same distance a 200mm lens at f8 has less depth of field than a 100mm lens at f8. Disadvantages • Larger and heavier than a normal lens • Somewhat more expensive • Its largest aperture is relatively small. f4 to f5.6 is common. There are faster lenses but they come with a price. • A faster shutter speed is needed to keep the image sharp while hand holding the camera. These disadvantages increase as the focal length increases.
Explain auto, program, aperture-priority, shutter-priority, and manual exposure modes.
Auto mode- sets both aperture and shutter speed for you. This will allow you to concentrate on composition, lighting and action. Program mode - sets the shutter speed and aperture just like auto mode, but also gives you access to more settings then you can access in Auto mode. Some cameras have a Program shift feature that allows you to cycle through a series of aperture/shutter speed combinations that offer equivalent exposures. By choosing the right combination you can choose to emphasize depth of field or capture motion. Preset Exposure modes -are fully automatic, but each is designed for a specific situation such as portraits, landscapes, night scenes, panoramas, and movies. Shutter-priority mode allows you to choose the shutter speed and the camera automatically sets the aperture. Select this mode when you want to control the appearance of motion. You can select a fast shutter speed to freeze the action or a slow shutter speed to blur it. Aperture-priority mode allow you to select the aperture and the camera automatically sets the shutter speed. Select this mode when control of depth of field is important. Select a small aperture to make everything in your image sharp such as in a landscape. To keep the subject sharp and blur out the background, select a large aperture. Manual exposure mode- allows you to set both shutter speed and aperture. Select this mode when the other modes cannot give you the results you want or when using studio lighting.
. Define depth of field and explain what affects it.
Depth of field is the area in front of and behind the point of focus that appears sharp. It is how much of your image appears sharp. As your aperture gets smaller, the more the depth of field increases and more of the scene from near to far appears sharp in your image. f2.8 will have less sharpness and f22 would have most of the image sharp. Depth of Field is controlled by 3 things: Aperture - smaller the lens opening the more area that will be sharp. Focal length of the lens - Longer the focal length the less depth of field you have. Camera to subject distance - Closer you are to your subject the less of depth of field you will have.
. What is depth of field and how can you control it?
Depth of field is the area in front of and behind the point of focus that appears sharp. It is how much of your image appears sharp. As your aperture gets smaller, the more the depth of field increases and more of the scene from near to far appears sharp in your image. f2.8 will have less sharpness and f22 would have most of the image sharp. Depth of Field is controlled by 3 things: Aperture - smaller the lens opening the more area that will be sharp. Focal length of the lens - Longer the focal length the less depth of field you have. Camera to subject distance - Closer you are to your subject the less of depth of field you will have.
What is focal length and how does it affect magnification and angle of view?
Focal length of a lens is the distance between the optical center of the lens and sensor. Focal length controls angle of view and magnification. Angle of view is the amount of the scene shown through the lens. Magnification is the size of the of the image formed by the lens. A lens is described in terms of its focal length.
How do you hold a camera?
For horizontal shots - keep your arms against your body to steady the camera. Use you right hand to hold the camera and your right forefinger to press the shutter release. Use your left hand the help support the camera or to focus or make other camera adjustments. For vertical shots - Support camera from below in either your right or left hand. Keep elbow against your body to steady the camera. A tripod steadies the camera for you and lets you use slow shutter speeds for night scenes or other situations when the light is din. Make sure to use a cable release, remote trigger, or self-timer with it.
What is ISO and how do you control it?
ISO is the third factor you can control when choosing an exposure. The sensitivity of a sensor is measured and rated using the ISO system which in the beginning rated film sensitivity. A sensor using a higher ISO rating will allow you to shoot in lower light settings, but it will also create images with more noise. You can set ISO from shot to shot unlike its film counterpart.
Explain the three types of in-camera meters.
Matrix metering - divides the image area into a grid and meters the light coming from each cell. These readings are analyzed and averaged to calculate the ideal exposure for a shot. Center-weighted - meters the entire scene but assigns the most importance to the center quarter of the frame where the most important objects are usually located. Partial Meter - meters the cells in the center of your frame. The size is usually about 10 percent of the total frame. Like center weighted, partial also provides a way to meter scenes with back-lighting troubles. Spot - evaluates only a small area in the middle of the viewfinder. This allows you to meter just a specific part of the scene instead of relying on an averaging meter reading. This mode is ideal when photographing a subject against a bright or dark background.
How do you bracket a shot?
One way to ensure you get the best exposure is to take three exposures. The first would be at the recommended settings. The second would be one stop overexposed and the third one stop underexposed, This process is referred to as bracketing.
Describe the differences between RAW, .tiff and .jpg formats.
RAW- Does not conform like the others do. It has more quality and control. Billions of colors and does not lose quality. .tiff- Universal program. There are no changes to it (lossless or compression). Can be compressed or uncompressed. .jpg- Compresses photos to a smaller size. The compression is called lossy. Every time you open and re-save you lose quality.
What are shutter speeds and how do they affect exposure and motion?
Shutter speed is measured in seconds. The longer the shutter speed will expose the sensor to light for a longer time than a shorter shutter speed. Shutter speeds can range from 30 seconds to 1/8000th of a second. Depending on you camera's capabilities. The standard full stop shutter speeds are: B, 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000, 1/2000, 1/4000, 1/8000 B stands for bulb. Its a setting that the shutter will remain open as long as you hold down the shutter button. This allows you to shoot exposures longer than 30 seconds. Although speeds faster than one second are fractions most cameras display them without the numerator. These shutter settings have been arranged in a sequence so that each setting lets half as much light as the next slowest setting and twice as much as the next fastest. From 1/125 to 1/250 you have half of the time, and from 1/250 to 1/125 you double the time. Many high end digital cameras have added two stops between each of the traditional ones. This allows you to adjust exposure in one-third stop increments for finer exposure control. In addition to controlling exposure, the shutter speed controls how motion will be recorded. A longer shutter speed will blur a moving subject and the more likely you are to cause blur by moving the camera slightly. A faster shutter speed will freeze a moving subject
What are apertures and how do they affect exposure and sharpness?
The aperture can be opened up to let in more light and closed (stopped down) to let in less light. The larger the aperture opening, the more light is allowed to reach the image sensor for a given time. This will result in a lighter image. Apertures settings are called f-stops and indicate the size of the aperture opening inside the lens. Each f-stop lets in half as much as the next larger opening and twice as much as the next smaller opening. The standard lens f-stops are f2.8, f4, f5.6, f8, f11, f16, f22. As the f-stop number gets larger, the smaller the aperture opening. If you went from f4 to f2.8 you double the amount of light. Then, if you went from f8 to f11 you would have only half of the amount of light. On some digital cameras, there may be one or two settings before the traditional stops. This allows you to change the aperture in fine increments of 1/2 or 1/3 stops. Aperture also controls depth of field. A small lens opening will have greater depth of field. which means that most of the image will be sharp. A larger lens opening will have narrow depth of field which means less will be sharp.
How do you care for a camera?
The cameras you buy today are very durable, as long as you keep it clean, dry, protected from temperature extremes, and don't drop or smash it into things. They require basic camera care just as any optical and electronics device would require. Cleaning supplies: • Lens Cleaning Supplies—Use lens tissue and lens cleaner to remove smudges on your lens. • Sensor Cleaning Supplies—Read your camera manual to see what the manufacturer requires. • Blower Brush—This will help dust off the sensor and blow out the inside of the camera. Be very careful and follow the camera manual. Do not use compressed air to clean the inside of the camera. Protect your Camera and Lens 1. Protect from dust and dirt Use cases to protect your equipment. Cases will protect your equipment from impact and will help keep it clean. 2. Protect from temperature extremes Avoid storage places where heat builds up such as a car trunk or glove compartment. Excessive cold is not as bad but can make the batteries sluggish. Moisture can also condense on the camera when shooting outside on a cold day. Wrap the camera in a plastic bag and let it warm up gradually. Moisture will form on the bag and not on the camera 3. If you won't be using the camera for a while Make sure the camera is turned off and store it in a cool dry place. If it will be stored for a longer time, remove batteries to prevent corrosion..
List and explain the various exposure controls.
The exposure compensation control A feature in your camera that allows you to adjust exposure without having to adjust shutter speeds and apertures. The auto, program, aperture-priority, shutter-priority, and manual exposure modes Auto mode- sets both aperture and shutter speed for you. This will allow you to concentrate on composition, lighting and action. Program mode- sets the shutter speed and aperture just like auto mode, but also gives you access to more settings then you can access in Auto mode. Some cameras have a Program shift feature that allows you to cycle through a series of aperture/shutter speed combinations that offer equivalent exposures. By choosing the right combination you can choose to emphasize depth of field or capture motion. Preset Exposure modes - are fully automatic, but each is designed for a specific situation such as portraits, landscapes, night scenes, panoramas, and movies. Shutter-priority mode - allows you to choose the shutter speed and the camera automatically sets the aperture. Select this mode when you want to control the appearance of motion. You can select a fast shutter speed to freeze the action or a slow shutter speed to blur it. Aperture-priority mode allow you to select the aperture and the camera automatically sets the shutter speed. Select this mode when control of depth of field is important. Select a small aperture to make everything in your image sharp such as in a landscape. To keep the subject sharp and blur out the background, select a large aperture. Manual exposure mode - allows you to set both shutter speed and aperture. Select this mode when the other modes cannot give you the results you want or when using studio lighting.
How do you use the light meter in your camera?
You aim your camera at your scene and press the shutter release button halfway down. This activates the light meter in your camera. Then you use the command dial to adjust your shutter speed and aperture so that the light meter scale indicates a good exposure.