FE Lock on 350D

[stoppable]

I have been using my 350D for almost 2 years now.
Something that I have always thought was working may not be. 
I use my 350D with a 580ex speedlight.

What I am not sure is if the FE lock works when the camera is set to manual exposure mode.  The flash being set to ETTL II mode.  I do this sometimes but results seem inconsistent.

[Michael]

If your camera is on a metering system such as Av Priority or Shutter Priority, that's when the FE lock comes into play. For flash on Manual, it's up to the photographer to determine his settings liao lei...

[stoppable]

If your camera is on a metering system such as Av Priority or Shutter Priority, that's when the FE lock comes into play. For flash on Manual, it's up to the photographer to determine his settings liao lei...

Is this the same for 400D or 40D as well?
Sadly, the manual doesn't say anything about FEL being limited to Av and Shutter priority in the creative zone. 
Going by what is stated in the manual, it only say that the flash output will be adjusted.  Given that at the point of locking FE (in manual mode for camera), my shutter speed, aperture and ISO values are fixed, it would not be too hard for the camera to calculated the required FE.  This is simpler than on, for example, Av mode, where the shutter speed and the FE have to solved.

[Michael]

if u're already on manual mode on your camera, what's stopping you from doing the same with your flash?

i've never really trusted E-TTL on Canon, even their ETTL II, probably with a pro body and a 580 II, but other than that, never.

here's a good method to use.

1) set your camera to the ISO you want
2) choose 1/250 (or max flash sync)
3) pick an aperture of f8 and smash at about 1/8th power of flash
4) balance the aperture with the power of the flash

[hwchoy]

in manual mode the flash is the main light, whereas it only work as fill in Av / Tv modes.

[stoppable]

thanks for all your suggestions.  I guess I will conduct a few experiments over the weekend, just to confirm how it functions. 

[victor]

I don't really trust the metering mode on the camera. Usually I will adjust my flash before the actual shoot, and shoot it in manual mode for both camera and flash.