Can anyone confirm if this behavior is consistent with other Canon cameras and attached and non-attached flashes?
With NO flash attached: Canon S5 IS set for Tv, 1/125th, ISO 80. The results when holding down the shutter button half way to see what the actual exposure will look like - the image displayed in the LCD is a very dark image and showing a f/2.7 and I think this would be normal.
But...when I attach the 430EX and it's NOT turned on (it's just sitting in the hot shoe), the LCD no longer shows you what the actual exposure will look like when holding the shutter button half way, it shows you the entire scene as it looks to your naked eye and is ignoring the shutter/aperture settings (you no longer see the dark image).
Is it normal for an attached flash that is not even turned on to affect what is displayed on the LCD?