Button for FEL

Hello
I am using * to focus on my 30D ( CF4-1) , then what button do I use for FEL ?
Thanks for your help
Neil B.

The only button you can use is the "*" button. So you'll need to make a choice, Im afraid, between either using it for focusing or for FEL.

Oh, I forgot, there is one other choice but it'll be a much, much more expensive option....switch to a 1D series camera (they have a dedicated FEL button).

Are you using the built-in flash or external?

Now this makes me wonder; what if you're using a 580ex, camera set to M and you use "*" to focus. Is there a need for FEL in this situation?

I use 430EX Flash unit
After focusing with the Center focus point, I recompose , that causes the center focus point move to different part of the subject. Since ETTL uses the reflective from the focus point to measure the output of the flash , I afraid that will cause the incorrect flash output for my picture. Am I right?

I'm not sure the focus point plays any part in the pre-flash flash exposure check. You can set it to use evaluative or center weighted avg.

This has been driving me nuts! Say I'm in Av or Tv mode. If I meter off one part of a scene with the flash up, and hit the * button to lock the exposure, when I go to recompose the exposure settings change. Why does it do this? I thought Flash Exposure Lock was supposed to lock in the exposure. It doesn't matter what CFn4-1 option I have my 40D set to, it does the same thing. Am I missing something here?

Sonno wrote in post #4833847
This has been driving me nuts! Say I'm in Av or Tv mode. If I meter off one part of a scene with the flash up, and hit the * button to lock the exposure, when I go to recompose the exposure settings change. Why does it do this? I thought Flash Exposure Lock was supposed to lock in the exposure. It doesn't matter what CFn4-1 option I have my 40D set to, it does the same thing. Am I missing something here?

Because with the flash up the * button is for "flash exposure lock", not "exposure lock". When the flash isn't being used it is for "exposure lock".

gooble wrote in post #4806025
I'm not sure the focus point plays any part in the pre-flash flash exposure check. You can set it to use evaluative or center weighted avg.

I believe that for ETTL the focus point was used. It isn't used for ETTL II.

gooble wrote in post #4804729
Are you using the built-in flash or external?

Now this makes me wonder; what if you're using a 580ex, camera set to M and you use "*" to focus. Is there a need for FEL in this situation?

Having the camera in M and using a 580EX does nothing to eliminate the need for using FEL. FEL is always useful when in situations where ETTL II will be fooled (lots of reflective surfaces, lots of white, lots of black, etc).

Sonno wrote in post #4833847
This has been driving me nuts! Say I'm in Av or Tv mode. If I meter off one part of a scene with the flash up, and hit the * button to lock the exposure, when I go to recompose the exposure settings change. Why does it do this? I thought Flash Exposure Lock was supposed to lock in the exposure. It doesn't matter what CFn4-1 option I have my 40D set to, it does the same thing. Am I missing something here?

If you have the flash mounted and turned on, hitting the "*" button will lock the flash exposure (assuming the "*" button hasn't been reassigned to focusing) as you would expect it to do. Now, when you go back to recompose the frame, you say that you're seeing the exposure settings change. That's also very likely. But here's the thing. When the flash exposure is locked, you won't actually see that in your viewfinder other than to have the "*" icon light up. The shutter speed and aperture settings you see in the viewfinder, in Av or Tv mode, is for the ambient light metering which does not necessarily have to lock unless you're in Evaluative metering and OneShot modes or C.FnIV-1 has been set to 3.

PacAce wrote in post #4834192
If you have the flash mounted and turned on, hitting the "*" button will lock the flash exposure (assuming the "*" button hasn't been reassigned to focusing) as you would expect it to do. Now, when you go back to recompose the frame, you say that you're seeing the exposure settings change. That's also very likely. But here's the thing. When the flash exposure is locked, you won't actually see that in your viewfinder other than to have the "*" icon light up. The shutter speed and aperture settings you see in the viewfinder, in Av or Tv mode, is for the ambient light metering which does not necessarily have to lock unless you're in Evaluative metering and OneShot modes or C.FnIV-1 has been set to 3.

I'm using the internal flash.
So there's a difference between exposure lock and flash exposure lock. Gotcha. Pardon my ignorance, but what exactly does FEL do and why would I need to use it?

Thanks!

Sonno wrote in post #4834303
I'm using the internal flash.
So there's a difference between exposure lock and flash exposure lock. Gotcha. Pardon my ignorance, but what exactly does FEL do and why would I need to use it?

Thanks!

FEL, as the name implies, locks the flash exposure and works basically the same way AEL works to lock ambient exposure. And the application is the same, too, i.e. to get a better exposure by locking the exposure on something closer to mid-toned, like a part of the subject or some other object nearby, if the subject is too dark or too bright. If what you FEL on is not part of the subject, it needs to be the same distance from the flash as the subject is because, as we all know, the brightness of the flash light is inversely proportional to the square of the distance to the subject.

When using FEL, the flash meter is locked using the area in the circle in the center of viewfinder.