Transcript Filters & Flash

Filters & Flash
COM 241
Photography I
Color Filters
• Tungsten (indoor) light
– Tungsten light gives image yellowish cast
• Blue filter (80A)
• Lose 2 f-stops
• Fluorescent light
– Gives image blue/green cast
• Use FL or 30M filter (magenta filter)
• Lose 1 f-stop
• To set WB
– Press WB button
on camera back
– Set white
balance to AWB
or desired setting
by turning dial
while looking at
LCD panel
All purpose filters
• Neutral density
– Absorbs light from all parts of light spectrum
– Comes in various densities
– Lose about 1 to 13 stops
• Skylight
– Used to protect lens
– No lose in f-stop
– Also eliminates ultraviolet light
• Polarizing
– Reduces reflections
– Also darkens blue sky
– Lose about 1 stop
Critique of direct flash
• Throws unnatural black shadows behind
subject
– Lighting usually looks too harsh
• Sometimes there’s uneven lighting
– Subjects in front look lighter, in back darker
• Sometimes get bad reflections
– People wearing glasses
Problems with using direct flash:
Uneven lighting
(light foreground, dark background)
Bright spots,
reflections
Dark, sharp shadows
Ceiling
Bounce flash
Subject
• Advantages:
Strobe
– Diffused lighting
– Even illumination
• Usually aim strobe at ceiling and bounce
flash off the ceiling
– Lighting that bounces covers a larger area when
it reaches subject
– Scene is more evenly lit, and diffused
To photograph this drug search, the photographer used the light
from a small portable strobe bounced off the ceiling. Bounce
strobe spreads an even, almost shadowless light throughout the
room. Joanne Rathe Strohmeyer / Boston Globe
• Can also bounce light off a wall
– More directional effect
Subject
Strobe
A 45-degree
bounce flash can
look like natural
light. Here one
flash was bounced
off the corner
between the ceiling
and wall.
With strobe bounced off a wall
outside the picture area, the light
appears to come from the
candles. Mimicking available light
with strobe increases the overall
illumination without losing the
natural feel. Ken Kobre / Boston
Phoenix
When a bounce flash works best
• Small to medium size room
– Auditoriums don’t work
• Need a light-toned surface
– Dark walls absorb the light
Change the ISO
• Use for low light situations
– Allows higher shutter speed or smaller aperture
• 100 / 200 / 400 / 800 / 1600
– Each increment doubles camera’s sensitivity to
light
– 100 > 400
• Shutter speed 15 > 60 or f-stop from f-4 to f-8
• On Cannon digital
cameras to change
ISO:
– Push up arrow on
back of camera
– ISO is displayed
on back LCD
panel
– Use dial to
increase or
decrease ISO
• Advantages: shoot in low light situations
w/o direct flash
• Disadvantages: print is grainier, less
resolution as ISO increases