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Basic Photography Using Flash

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Basic Photography Concepts

• Automatic vs. Creative Modes

• EV Equivalent Value

• Lighting considerations

• Histogram

• Add Flash to you shot

• Guides as starting points

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Automatic vs. Manual

• Automatic is easy

• Quality is good • I’m in a hurry

• Manual is difficult

• To many things do I need to think about.• What are the advantages?

• The difference is consistency and control.

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Automatic vs. Creative Modes

• To what extend do you want to have control?

• Creative modes– AV , TV, P– Manual

• Custom Features– First curtain vs. second curtain– High speed sync

• Histogram

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Histogram in Camera

• To the left the picture is to dark, to the right it’s too bright

• Balanced is in the center• A valuable tool in camera

To dark To bright

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Exposure Value

• Three choices, all with limitations– Aperture 22, 16, 11, 8, 5.6, 4, 2.8, 2, 1.4,1.2

– Shutter Speed100, 200,400,800.…8000

– ISO- 100, 200, 400, 800,1600…. 24,000

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Lighting Considerations• What is your main light source?

• Direction of the light• Color Temperature

• What affect do you want?• Digital camera metering to 18% gray

• Increase exposure for white• Decrease exposure for black

• Do I want, or need flash?

                

                

                

                

                

                

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Using On-camera Flash

• Built in flash unit• Add on flash units

– A or B type units– EX vs. EV units– Metering with TTL– Consider using EV changes on flash unit

• Camera Sync Speed• Considering a purchase?• Off camera flash – subject for another time

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Light Fall-Off(Inverse Square Law)

Light Source

Illuminated area = 1 sq ft

Illuminated area = 4 sq ft

5ft 5ft

For a given light source intensity:- Twice the distance results in 1/4th illumination (i.e., 2 stops lower)- Three times distance results in 1/9th illumination (i.e., >3 stops lower)- Four times distance results in 1/16th illumination (i.e., 4 stops lower)

Solutions:- Decrease distance between closest & furthest subjects- Back away from closest subject as much as possible- Use Large Diffuser (limited effectiveness when on-camera)- Use Bounce Flash (back wall, side wall, ceiling, reflector)

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Flash Unit Guide Number

Guide Number shows the power of the flash unit.

Useful tool to estimate exposure when distance is known:

Guide Number / distance in feet= Aperture580 EXII 7D

(mm) 14 15Guide No 49 39

f / (ft) (ft)2.8 18 14

4 12 105.6 9 7

8 6 511 4 4

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Add Flash to Composition

• As your primary light – Soft vs. hard light (demo flash)– Direct vs. indirect light (demo)– Light fall off (demo)– Ambient light (Demo)– Color Temperature (demo)

• Used a supplemental fill light – Control shadows, Highlight subject, Create soft light, Contrast

• Light fall off– Flash on subject is not affected EV, background is (Demo)– Adjust EV as subjects appear further away (Demo bounce flash) – Guide Number / distance in feet = Aperture

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Direct vs. Indirect light

• Direct light removes shadows and creates a flat picture.

• Direct light is a hard light• Bounced flash softens light and skin tones

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Soft vs. Hard Light

• Look at the skin tones between a soft and hard light.

• Notice reflection of light from flash

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Light Fall Off

• Example shows how illumination is less the further apart the subjects are from the source.

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Solution for Light Fall Off

• Consider bouncing flash to balance illumination on subjects at different distances.

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Ambient Light

• In addition to your main light, you need to consider ambient light.– Tungsten add an orange color – Fluorescent – blue of green tint added

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Watch out for glasses!

• Direct light reflects off glasses. • Also, “Red Eye” comes from reflection off of

the eye retina.

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Color Temperature Solution

• Convert your flash to correct ambient light

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Light Fall Off

• Using Flash the light remains constant– Flash on subject is not affected by change in EV– Background illumination can be controlled with

EV

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Notice the back ground!

• By just changing the shutter speed you control the color and texture of the back ground.

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Want more Shadow?

• Add flash and to the extreme. • Adjust the angle and distance of the flash to

control shadows.

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Live Demo

• Grey scale demo showing manual vs auto exposure modes.

• Color demo showing manual vs auto color selection

• Additional examples

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Starting PointsConsiderations/Rules of Thumb

• Read your equipment manual!• Daylight- Rule 16: A 16, SS 100, ISO 100• Flash on subject in Sun light

– Sun behind camera -3EV to -1EV– Sun at 90 degrees -2EV to 0EV– Sun behind subject -1EV to +1EV

• Indoor consider your color temperature• Consider bounce flash to direct or soften light• Consider shutter speed & ISO to supplement background• Shoot Raw to have 16 bits of data per pixel to work with for flexibility• Look at the camera’s RGB histogram • Shoot a manual practice shot, then adjust the settings to your

preference• Play with flash - practice