Quote:
Originally Posted by MattUK
Chris, when you say auto mode, what do you mean exactly? Auto mode on the flash gun? If you can't use it in 'auto mode', then what'd the downside? Do you need to plug a whole bunch of settings into it each time?
Thanks for the help
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Yeah, an auto mode on the flash gun.
Basically, if you let the flash run in TTL mode, the camera tells it how to behave. You often have two TTL types, the first of which is "Full" TTL (Canon call it e-TTL and Nikon call it iTTL) where the camera knows the flash is attached and meters for the scene, adjusts the flash output to suit and fires the flash when you shoot. The camera tells the flash how much power to use.
The second type is sometimes called Aperture TTL or aTTL (or similar) which is when some, but not all, exposure information can be passed between camera and flash. In this instance the flash usually meters the scene as well but gets told the aperture of the lens so the flash itself adjusts it's output, not the camera.
If you don't have any auto functions on the flash you need to dial in the correct flash power yourself. Not a problem in itself but if you don't have a way of metering the scene or you don't have enough experience to be able to look at the scene and say "oh, I reckon thats about 1/50th at f/8 with about 1/64 flash at 4 metres" it's has to come down to guess work. Fine for still life photos but rubbish when you're trying to get something thats moving.