novice flash help.

[placeonthecorner]

hello! . i just got a sigma ef-530 dg st to go with my 30d .. can someone explain how it works?!?!?! .. its simple enough to use with the auto mode, but i want to shoot raw so i need to go manual .. how do i figure out exposures etc? .. so far they have all been very over exposed .. sorry for the complete noviceness of this

 

[Big Mike]

but i want to shoot raw so i need to go manual

What? You don't need to be in manual to shoot RAW.

Your camera has FEC (flash exposure compensation)...I'm not sure if it works with a non-Canon flash. If not, the flash probably has the same control. You can use FEC to control how much flash exposure you will get.

The flash is (I'm fairly sure) a dedicated model...so it will adjust it's power to the aperture that you are using. It fires a pre-flash to meter the light, then fires again, with the power that it thinks is correct. This will be dependant on the reflectivity of your subject...so you may need to use FEC to change it.

You can use the flash in manual mode...and probably adjust the power right on the flash. You can use this in conjunction with the aperture of the lens, to get the flash exposure that you want. The shutter speed won't affect the flash exposure but will affect the exposure from the ambient light.

If you are not sure about it...just start with both the camera and flash in auto. If you want to try some trial and error...put the camera and flash into manual mode and start testing different settings.

 

[placeonthecorner]

ah ok i was a little confused .. the instructions were non existent so i think trial and error is the best thing .. just one other thing .. it says it has a guide number of 30... whats that mean?