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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