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Digital cameras. Understanding Resolution &. Understanding Resolution. Resolution is determined by how many pixels (picture elements) or dpi (dots per inch) are available. - PowerPoint PPT Presentation
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DigitalDigital camerascameras1
Understanding Resolution &Understanding Resolution &
Understanding Resolution• Resolution is determined by how many
pixels (picture elements) or dpi (dots per inch) are available.
• The image you see is simply a grid ofsmall squares or circles filled in with color. The more squares or circles—the sharper the image.
Measuring Resolution
• Resolution is measured by the number of horizontal pixels times the number of vertical pixels– Example: 3072 x 2304
Megapixels• The quality of a picture is primarily
measured by its resolution—how many pixels it has; the current measurement is in megapixels
• A megapixel is a grid containing one million pixels (one million squares of color)—technically, that is an image with a resolution of 1024x1024 pixels
Three Resolutions to Consider• Image
– Measured in pixels– Can be changed on the camera– High res = clear pix = large file size
• Monitor– Measured in horizontal vs. vertical
pixels. Ex. 1024 x 768
• Printer– Measured in dpi (dots per inch)– Quality of print will depend on image AND
printer resolution
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Digital Cameras
• There are two primary categories of digital cameras– Point and shoot– Digital Single Lens Reflex (SLR)
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Point and Shoot Cameras• Most digital cameras designed for the consumer
(vs. professional) are point and shoot cameras• They fall into three categories:
subcompact, compact and super zoom
• The camera lenses are built-in (not removable)• Basic features typically include auto focus, auto
exposure and built-in flash• Not appropriate for action
photography because of lag time
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SLR Cameras (Single Lens Reflex)With an SLR camera, you see exactly
what the lens sees You can change the lens on a digital SLR
◦ You choose the lens based on the type of photography; example: portrait photography vs. sporting events vs. landscape photography, etc.
SLRs produce higher-quality photos than point and shoot cameras
An SLR has a near-zero lag time, and is ideal for action photography
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Other points to consider• When purchasing a camera, you should also
research the following specifications:– Storage Capacity– Transferring Images– Power Source– LCD vs. Optical View Finder– Zoom– Image Stabilization– The Exposure Triangle (Aperture, ISO, Shutter Speed)
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Storage Devices• Memory Card• Internal Memory (RAM)• The number of pictures you can take
before sending them to your computer is determined by two things:
• The resolution of the image• The type of storage
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Transferring Images
• Card reader • USB cable• Bluetooth
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Power Source• Regular Batteries• Rechargeable batteries– Alkaline– Nickel-metal hydride (NiMH)– Lithium-ion (Li-Ion)
• AC Adapter
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LCDs vs ViewFinder
• LCD—Pro’s– Shows you the exact image
that will be recorded– Easy to view … delete images,
etc.– Displays menu
• LCD—Con’s– Drains battery—uses ½ life of
battery– Difficult to see in bright light
• View Finder—Pro’s– Uses less battery– Easier to see images in bright
light
• View Finder—Con’s– Shows close approximation of
the final image—not the real thing
– Difficult for some people to see
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Zoom• Optical zoom actually enlarges the image– Measured in X
• Example: 8X—increases an image 8 times
• Digital zoom takes a portion of an image an enlarges it electronically; – The image loses resolution when the camera enlarges it; also
measured in X
• Macro zoom allows you to take close-up pictures of objects that are small and enlarge them so they appear larger.
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Image Stabilization
• A feature in digital cameras that reduces the vibrations that can occur when taking a picture.– Vibrations commonly occur when shooting at slow
shutter speeds, with longer lenses or with digital zoom.
– Also called anti-shake
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The Exposure Triangle• Exposure is the total amount of
light you let into your camera. – Too much light results in an over-exposed image
where there are areas of bright white or ”blow-outs”. These areas contain no detail or color.
– Too little light and an under-exposed image leaves parts of your image too dark to make out details.
• The three components to exposure are ISO, shutter speed and aperture
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The Exposure Triangle
• ISO—the measurement of how sensitive the image sensor in the camera is to light.– Measured in numbers 100, 200, 400, 800, etc.– Use a lower number when smooth crisp images
are need and you have plenty of light.– Higher numbers are used when light is limited,
you do not want to use a flash, or the subject is moving; may result in grainy images
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The Exposure Triangle• Shutter Speed—the amount of time the shutter is
open—which determines how much light is captured in the recording process– Measured in seconds: super fast 1/2000 second to
30 seconds– The slower the speed, the longer light can enter
the camera. Appropriate for shooting pictures in darker situations; also great for freezing action and movement
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The Exposure Triangle
• Aperture—the camera feature that regulates the amount of light that passes through the lens by controlling the size of the opening in the lens– Described as the f/stop (a stop is a
change in setting)– The smaller the number the wider the
lens will open
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