Understanding Resolution &

Digital CamerasAnn Ware

Bald Knob High School

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ResolutionUnderstanding digital cameras requires that we

know how resolution works.

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.

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Measuring Resolution

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Resolution is measured by the number of horizontal pixels times the number of vertical pixels◦Example: 3072 x 2304

MegapixelsThe quality of a picture is measured by its

resolution—how many pixels it has; the current measurement is 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

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Resolution

With computer graphics, there are three different resolutions to consider:◦the image’s resolution (pixels)◦the monitor’s resolution (pixels)◦the printer’s resolution (dpi)

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Image Resolution

The image’s resolution is measured in pixels.

Most cameras allow you to change the resolution before you take the picture.

The higher the resolution—the clearer the image—the bigger the file size.

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Monitor Resolution

Monitor resolution is measured in horizontal and vertical pixels◦Example: 800 x 600

If an image is taken at 1024x768, but your monitor can only display 800x600—that’s as good as it gets!

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Printer Resolution

Printer resolution is measured in dpi—dots per inch.

The quality of the printed image is going to be determined by both the resolution of the image AND the resolution of the printer.

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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

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Storage Devices

Memory CardInternal Memory (RAM)

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Storage Capacity

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 cableBluetooth

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Power Source

Regular BatteriesRechargeable batteries◦Alkaline◦Nickel-metal hydride (NiMH)◦Lithium-ion (Li-Ion)

AC

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LCDs vs ViewFinderLCD—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

ZoomOptical 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 allows you to take close-up pictures of objects that are small and enlarge them so they appear larger.

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