Amateur help needed - The 580ex is a ton of flash

TaDa

I bought the Canon 580ex, and need some help with it. The manual is not a ton of help with E-TTL, and when I am shooting my son with my Canon 50mm 1.4 USM set to f1.4, pretty much every shot comes out overexposed, and I've tried bouncing the light off the ceiling, behind me, etc. and even with the wide panel down and an Omnibounce fitted on it, it still puts out a ton of light. I have had some success by stopping down the light +3, but believe that ETTL should be helping automatically throttle the output of light based on aperature and distance set? The flash is set to 50mm and it detects the 1.4 aperature, but still a ton of light. I noticed that my 50mm 1.4 USM is listed as a lens that may not capture distance, but isn't the 50mm in the flash's window calculated into the light output? This is my favorite lens to date and any help would be greatly appreciated so that I can stop making my son look like Casper the Friendly Ghost

Icebear

Let me preface by saying that I don't shoot Canon, so I'll let someone else try to steer you right, but I do have a question. Why in the world, with that powerful flash, would you want to shoot at f1.4 anyway???

zacker

dont use f1.4 try f8 or so, also, try putting the camera into AV mode.. it will automatically go to 1/250 for a shutterspeed and then you can adjust the Aperture from there to controll the light of the flash. If you wanna get some natural (ambient) lighting i the shot, use Manual mode on your cam and adjust the Aperture to your desired flash and use the Shutter speed to controll how much ambient light comes in. So in review... Aperture (f stop) controlls the flash lighting
Shutter speed controlls the Ambient lighting.

rwells

zacker wrote:

dont use f1.4 try f8 or so, also, try putting the camera into AV mode.. it will automatically go to 1/250 for a shutterspeed and then you can adjust the Aperture from there to controll the light of the flash.

Unless C.Fn 3 has been enabled (not sure about the Rebel, but this is the way it works on a 30D), then this part of the statement is inaccurate. Also, in ETTL mode, the flash will (try to) compensate for the different aperture settings to try and accomplish its "fill" lighting task.

By default, when in AV mode and the flash in ETTL, the camera will use the flash as "fill" flash. You set the aperture (AV mode), and the camera will set the shutter speed to properly expose the scene. The flash set to ETTL will "fill" in as needed to provide soft(er) shadows.

Also, if you are dialing in "+3" FEC, that's forcing the flash to put out MORE light, not less. That's on any Canon camera body.

There are some threads that Scott, Pathfinder, LiquidAir & myself have given in-depth details about using Canon's AV mode and ETTL flash. If you can dig those up, It'll give you all the info you seek.

Again, I don't know if this holds true for a Canon Rebel, but it is correct for a 30D.


Hope that helps...

TaDa

Sorry, I meant -3, not +3. I am cranking down the light. I do shoot it in AV mode and shot the pics at 1.4 for the bokeh. And thanks for the advice on the threads. I've gotten to a few of them talking about canon flashes in general and will look for the ones about shooting in AV mode.

Eric&Susan

Grab about three pots of coffee and read this:

http://photonotes.org/articles/eos-flash/

Seriously it is way to much to read in one sitting but it is very useful once your done reading it and for a quick reference.

Eric

dmmattix

There is also a sticky at the top of this forum on EOS flash links. It has the link mentioned in this thread plus a number more. I have looked at the Photodo EOS flash site recently so I do not know if it has been updated to cover ETT-L II or not and there are some differences.

jeffreaux2

There is a high speed synch mode on that flash that will enable you to use higher shutter speeds than the synch speed of 1/250. It's all in the manual. It works very well outdoors, in otherwise good light, using wider aperatures and shutter speeds at least as high as 1/1000. I am not sure if there is a limit to the shutterspeed when using the flash in this mode other than the cameras own limit....usually 1/4000 or (?) depending on the model. If you want less flash you have to have minuses in front of the numbers for FEC.....but as Randy says, Canon automatically does this for you to a degree when in AV mode.

Someone asked why use an aperature like that with flash?

For depth of focus control in portraits is a good reason.