E-TTL and Manual lowest exposure possible

<span class="postbody"]Hello,


A couple of days ago I bought a Canon 580 EX II and while experimenting
with it I found something odd (at least it seems to me so http://www.cameralabs.com/forum/imag...n_confused.gif ):


I took two photographs with the same Aperture setting, Shutter Speed,
ISO and using the 580. The only difference is that in the first picture
ETTL mode was used and on the second Manual Mode with flash output set
at 1/128th. The second picture was more exposed than the first picture,
I tried it again many times but the results are the same, I must be
missing something but what? I would be very grateful if you could help
me. http://www.cameralabs.com/forum/imag...on_biggrin.gif


Here's an example:


http://img14.imageshack.us/img14/2356/mg8284.jpg


http://img121.imageshack.us/img121/8435/mg8285.jpg

P.S.: The head zoom was not changed during these shots, <span class="postbody"]I've also found out that if I use flash exposure
compensation in E-TTL mode, I can further decrease the exposure, but I
cannot find a away to do it in Manual mode. Same thing with External Metering Mode in which the flash exposure can be limited to a very subtle light.
<span class="postbody"]
Camera: EOS 400D


Lense : EF 50mm F/1,4


Thanks in advance, and greetings from Greece! http://www.cameralabs.com/forum/imag...on_biggrin.gif

What is it that's odd?


E-TTL control does allow a lower power output from the flash than manual power setting can reach, but that's in the design. If you didn't know, then that's perhaps what's odd?


If you need to use manual power in such cases, you have to lower the ISO and/or stop down the lens, to make it work.

I suspected that this was the case but I was not sure, thanks for your answer.

The first on(ETTL) looks a bit under exposed. This is because there is so much white in the frame. The light meter does not know it is white. When there is a lot of white in the frame you need to dial in some exposure compensation.


Mark