Basic Flash Process

• Every Flash photograph is two exposures in one.
• Fill flash can be used when subject is backlit to eliminate silhouettes or shadows
• Flash exposure is not affected by shutter speed.
• The flash exposure and the effective range of your flash unit will be affected by aperture and ISO settings, but not the shutter
• Flash illumination is dramatically affected by distance
• Your camera measures ambient light and flash illumination separately 
• With Automatic flash metering, the flash illumination is measured after the shutter button is pressed , and the flash output is adjusted accordingly
• Every SLR camera with a mechanical shutter box has a maximum flash sync shutter speed.
• Harsh Lighting, washed out subjects and red eye can be eliminated by using diffusers and light bouncing.
• Is it possible to change the order of when the flash fire using "Rear Curtain Sync".
• Removing the flash from the top of the camera helps eliminate the red eye and unflattering shadows .
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