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Camera Usage. Photography I COM 241. Single lens reflex camera. Uses interchangeable lenses Higher quality image than point and shoot cameras Greater resolution DSLR Digital single lens reflex. Exposure. Shutter speed + aperture = exposure
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Camera Usage Photography I COM 241
Single lens reflex camera • Uses interchangeable lenses • Higher quality image than point and shoot cameras • Greater resolution • DSLR • Digital single lens reflex
Exposure • Shutter speed + aperture = exposure • Basically correct exposure tells camera how much light to let in camera to produce the best possible image
Shutter speed controlled in camera • Shutter opens and closes • F-stop controlled by lens • Size of hole that light comes thru • Both control how much light let into camera
Shutter • Amount of time the shutter is open • Controls amount of light that enters camera • Settings are in fractions of a second • So a shutter speed of 4 = 1/4 of a second • A shutter speed of 60 = 1/60 of a second
Each shutter setting is half (or double) the next • Typical shutter speeds • 1, 2, 4, 8, 15, 30, 60, 125, 250, 500 • Little different on digital cameras
Slow shutter speed – 1/8 to 1/30 of a second Fast shutter speed – 1/125 to1/500 of a second
Bike rider: slow shutter speed during the day (pan shot) Car lights: slow shutter speed at night (time exposure)
Camera motion • Faster shutter speed, less camera movement • Longer the focal length of lens, more have to worry about camera movement • General rule of thumb • Shutter speed greater than or equal to focal length of lens*
Aperture • Opening in the lens thru which light enters camera • Control this by making opening larger or smaller • Measured by f-stops • f/1.4, f/2, f/2.8, f/4, f/5.6….f/64
The aperture, or hole in the center of the lens, gets smaller as f number or f-stop increases
Each f-stop is half as fast as the previous one • f/1.4 is largest and “fastest” • Admits the most light • When go from f/2 to f2.8, that’s referred to as “stopping down”
Shutter closed Shutter open
Depth of field/aperture • Area of focus is known as depth of field • As decrease size of aperture, depth of field increases • More in photo (background and foreground) is in focus
shot at f/2.8 • focus is on boy in middle • aperture setting is f/16 • focus is on boy in middle
Determinates of depth of field • Aperture • Smaller aperture, greater depth of field • Lens • Shorter the lens, the greater depth of field • Wide angle vs. telephoto • Distance from subject • Greater distance from subject, greater depth of field
Aperture / shutter speed • Each smaller f-stop cuts amount of light in half • Each increase in shutter speed cuts amount of light in half • Maintain the same exposure by: • Increasing shutter speed, decreasing f-stop • Or vice versa
Open up f-stop, use faster shutter speed 500 / f2 250 / f2.8 125 / f 4 60 / f5.6 30 / f8 15 / f11 8 / f16 Correct exposure Stop down f-stop, use slower shutter speed
Difference is in motion and depth of field • Faster the shutter speed less blurring • Higher the f/stop (f/16) greater the depth of field
1/4 sec, f/16 • Small aperture (f/16) produces great depth of field • But bird’s wings are blurred
1/250 sec, f/2.8 • Freezes bird’s wings • Background is now out of focus
ISO • Sensitivity to light • Higher ISO, more sensitive to light • Good for low light, fast action • Makes image look more coarse, grainy
Low ISO gives better resolution • 100, 200, 400, 800, 1600 • Can change on each shot • Digital camera
Determinates of exposure • Shutter speed • Faster shutter speed, less light strikes film • Stop action • F-stop • Smaller aperture (f/16), less light strikes film • Depth of field • ISO • Sensitivity to light • 800 ISO is more sensitive than 200 ISO • Also looks a little grainer
Light meters • Reflected • Meters light reflected from subject • Built into cameras • Incident • Measures light falling on subject
What light meter “sees” • Averages all tones in a scene • Converts them to 18 percent gray
High contrast scenes • Light background • Causes subject to be underexposed • Dark backgrounds • Causes subject to be overexposed
How to compensate • Move in closer • Meter the palm of your hand • For landscapes tilt the camera down