Chapter 6- Outline

Digital sensors will provide proper colors under what three conditions?

lit with electronic flash

lit with midday sun

white balance set for current lighting

What is a means to discuss a flash unit’s relative output power?

guide number

When using flash, what is not as variable as they are when exposing images without flash?

shutter speeds

Equation to calculate guide number

GN= (f/stop)(distance between flash and subject)

Equation to calculate f/stop

f/stop= GN/ distance between flash and subject

What guide number is considered the norm for many LE agencies?

120

What is the shutter speed that has the shutter completely open when the flash unit fires?

sync speed

What must be avoided regarding sync speeds?

Using a shutter speed that is faster than the sync speed

With non-flash photography, what were the major exposure control and the primary control of motion? Is this the case with flash photography?

shutter speed, no

With flash photography, exposure is a function of what?

the intensity of the flash unit

With flash photography, what is motion control taken over by?

the flash unit’s duration

Most cameras have front curtain sync. What does that mean?

As soon as the canera’s shutter opens, the flash will fire

In manual flash mode, what power of the flash is used?

full power

In manual flash mode, what is the normal way to alter exposures?

change the f/stop

What do you need to diminish when taking close-up photos with manual flash?

the intensity of the full manual flash

Rule of Thumb 6.1- Most flash units are not designed to be used at distances closer than what? What should you avoid to ensure the flash doesn’t get too close?

2 feet

bending your elbow when holding the flash off camera

Manual flash presumes the flash is aimed where?

directly at the subject

Manual flash exposure calculations presume the flash is operating in a what?

normal room

When should you not trust the manual flash?

when the room is larger than normal

when the room is smaller than normal

when you’re outside

Rule of Thumb 6.2- Manual flash used outside is at least _ _ less bright than what is suggested by the LED screen.

one stop

Rule of Thumb 6.3- When you are 5’ or closer to your intended subject, what should you do with the flash head?

Remove it from the camera body so it can more accurately be aimed

What allows the camera to get as close as necessary to fill the frame while also moving the flash further away to prevent overexposure?

PC cord

What are three common problems with manual flash?

frequent f/stop manipulations (this is how exposure is controlled)

battery consumption

electronic flash recharge times

Rule of Thumb 6.4- How do you know when to change the batteries is an electronic flash?

When the recycle time is longer than 30 seconds

What are the four options to bracket when using manual flash?

change f/stop

change ISO

alter intensity of flash output

move the flash unit closer

What law explains the f/stop numbers?

inverse square law

Inverse square law: If you ? the distance light has to travel, you ? its intensity.

double, quarter

What is the equation to determine the new intensity for any distance change?

I= 1/(D²)

What is the equation to determine the distance change if a new intensity is known?

D= (square root of 1)/I

Each larger number (further distance) represents __ the light of the previous number, which is the same relationship as what?

half

the f/stop numbers

Besides aperture, what can f/stops be thought of as?

distances

What flash mode has a sensor eye that measures the amount of light reflected, and when it determines that enough light has been reflected, the flash duration is cut off

automatic

Rule of Thumb 6.5- When you are using flash, pretend the world about __ doesn’t exist because beyond that, what will happen?

42’ to 46’

the scene will either be underexposed or a wider aperture used, decreasing the DOF

What is a downside to automatic exposure mode?

the sensor eye can be fooled by non-normal scenes like the exposure meter in the camera

Automatic flash has its own __ to bracket exposures

exposure compensation dial

When using automatic flash exposure mode, the sensor eye cannot provide good exposures when ?

the flash is oblique to the subject

In what flash mode does light that enters through the lens get metered inside the camera body?

dedicated

Dedicated flash exposure modes have the same attributes as auto, but it is not affected by what?

if it’s used obliquely

If a flash unit has all three exposure modes, which is the best option?

dedicated

What are the three downsides to built in flash units?

low guide number

red eye will result when photographing people

very direct light and produced harsh hot spots

Fill in flash should be __ less light than the main light

1 stop

What flash mode is most appropriate when using fill flash?

manual

What are five types of evidence where oblique flash is useful?

footwear impressions

tire impressions

bite marks

indented writing

dust prints

What can be used for snow and sand impressions?

snow print wax

Must ensure you document the full circumference of the tire track, which is usually how long?

7.5 feet

As the 3D nature of the impression becomes less pronounced, what is more crucial?

the positioning of the oblique light

Upper and lower arches of bite marks should be what?

considered two separate sections and documented as such

Indented writing is best visualized with what kind of oblique light?

diagonal

What should you do to avoid flashlight streak when using oblique lighting?

keep the flashlight or flash moving during the photograph

Dust prints are right to left or left to right __

reversals

When to use bounce flash?

highly reflective surfaces and mirrors

Where should you aim bounce flash?

midway between you and the subject matter

Rule of Thumb 6.6- When using bounce flash, if the subject of the photograph is 9’ or farther from you, you may need to use an f/5.6 or wider, which will decrease your DOF. What else can you consider?

Ways to get closer to your subject

Bump the ISO higher

What are three variables that must be understood when painting with light?

tripod, camera, flash

Can be painting with light be done with one person?

Yes, if it’s dark enough to leave the shutter open without being blocked between flashes

Indicate one circumstance when it would be best to choose manual flash over automatic or dedicated.

examination quality photos

Indicate one circumstance when it would be best to choose automatic flash mode over manual or dedicated

small, outdoor scenes

Indicate one circumstance when it would be better to choose the dedicated flash mode over the automatic or manual.

This is recommended for all scenes when available