Electronic Flash
Lightening is a natural flash
Flash Powder
- Magnesium metal ground fine enough has the capacity to burn rapidly or explosives and produce and intense flash of light
- Early photographers used this technique to provide extra light or to ‘stop’ motion (1880’s)
- Electronic Flash created by Harold Edgerton, 1931
Flash Bulbs
- Magnesium Wire
- Powered by battery
- 1/50th sec shutter delay
- Bulbs and Magi cubes (4 bulbs)
Flash Colour Temperature
Cooler
- Mod Overcast Sky : 6500 - 8000k
- Daylight : 5000 – 6500k
- Electronic Flash : 5000 – 5500k
- Flash Bulb : 4000k
- Tungsten Studio Lamp :3200k
- Tungsten Household Lamp :2500 – 3500k
- Candle Light : 1000-2000k
Warmer
Electronic Flash Built into Camera
- Fairly low output
- Powered by camera
Portable Unit
- Powered by batteries
- Typically high output
- Sophisticated exposure control
- Multi-featured and many accessories
- Can be dedicated to camera exposure control
Electronic Flash – Monobloc
- Powered by mains supply (some with battery pack)
- Very high output capacity
- Variable output accessories eg. Umbrellas, reflectors
- Convenient for location work
- Moderately expensive
Electronic Flash : Studio Flash
- Higher output than monobloc
- Powered by mains supply
- Variable output
- Lots of accessories
- Extremely versatile, very expensive
Electronic Flash – Guide number/guide aperture
- Portable flash rated with a guide number
- Guide Number (GN) = f-number @1m @ ISO 100
- Monobloc and Studio Flash units rated with a guide aperture
- Guide Aperture (GA) = f-number @2m @ ISO 200
Inverse Square Law
Broncolor Pulso 2 Demonstration
Main Features
- Output Control – anywhere between 6 to 10. Each whole number alters the output by the equivalent of one stop.
- Symmetrical Distribution – Same power distributed between each head.
- Flash Guide Aperture : @ 2m and ISO 100 of f64 = Guide Number 128
- Modelling Light - Five settings, Proportional Mode
No comments:
Post a Comment