Dedicated / TTL OR ETTL
In its simplest form, put the flash in TTL mode, select any aperture on the lens and the flashgun will do the rest itself. It talks to the camera and tells it when enough light is used!! Most Dedicated flashes also allow full manual and auto control.
-very effective.
-what all pro’s use
Built-in flash
Little manual control is allowed. The camera may have features such as Flash On, Flash Off, Fill-in Flash, Slow Synch, Second Curtain, or Red-Eye Reduction. You choose the setting and the camera does the rest.
-very limited and weak
-convenient
Manual
Check the table on the flash: Choose an aperture and move the corresponding distance before you take the shot. Alternatively, estimate how far you are from the subject and, from the table, select the corresponding aperture.
-common in older flashes
-more technical
Automatic
Find the Auto settings on the flash, usually indicated by a red and/or blue spot. Select a suitable Auto setting and simply set your lens and flashgun to the same aperture setting and the correct exposure will be obtained.
FLASH SYNC
Every flash has a flash synchronization speed, meaning the fastest shutter speed at which it can work .
-usually 1/60, 1/125 or 1/250
-flash may be used at slower speeds without any problems.
-BUT, if used at a faster speed part of the image will be blacked out.
FLASH ON SHOE:
Using the flash on top of the camera, on the shoe can cause problems
-Red-Eye
-Harsh Shadows
-Variation in exposure in group shots,
or wide angle pics
Some On-Camera Flash problems may be solved by
-bouncing or using a bounce card
-diffusing, a soft box
Take the flash off the camera with a PC cable or Synch cable and hold, bounce, reflect where you wish.
FLASH PROBLEM SOLVING:
Red Eye: Bounce the flash, get subject to look at a bright light just before you shoot, ask subject to look at side of camera, not straight into the lens.
Part of image blacked out: Use the correct synch speed.
Hot Spot: Angle flash to bounce light off reflective backgrounds and not straight back to the camera. Move reflective backgrounds (mirrors) or move your angle of taking.
Overexposure: Make sure you haven't covered a sensor with your finger. Is film speed setting correct? Have you chosen the correct aperture for the distance to the subject? (Subject too close)
Underexposure: Flash may be set to a higher film speed than the camera. The aperture chosen may be too small. The subject may be too distant.
Image blurred: You have been using a longer shutter speed than the recommended synch speed and your shaky hand-holding is causing the blur. You may be deliberately looking for this effect when using SLOW SYNCH SPEED.
Color Cast: The flash picked up the color of the surface on which you bounced the flash. Normal un-bounced flash is set at daylight temperature to give white light.
Color Mismatch: The flash, which is daylight, doesn’t match color of ambient light. Use corrective gels.
