Having Wierd Flash Experience, Please Help

[Portlandstone]

Bought my 430EX over a year ago but just now starting to use it, with my 400D body. If I set the camera in P (auto) mode in evening or night, I get a wider aperature and about 1/60 shutter, and the result picture is a very well lit foreground as well as bright lighting in the distance about 30 yards (but very dark in the far distance, naturally), showing the 430ex indeed has some good power to it. However, if I go over to manual mode M for the exact same shot but switch to a longer shutter (say 1/2 second to 1 second) and roughly the same aperature, it appears the flash becomes much weaker because while the distant subjects far off are much better lit, the foreground is poorly so and even badly underexposed. It appears the flash or camera or both is figuring that with a longer exposure I need much less flash light, but I don't want to camera to think that much because now foreground is under. I want to get basically the same power of light in the longer manual shot that I get with a P auto shot.

Does this have something to do with "evaluative"? In simple english terms please explain what I should be doing. Thanks.

Oh yah as an addition, I also had the frustration that my flash wouldn't fire at all for a whole day (yesterday). I found out that somewhere in the connection points (either on bottom of flash or on top of camera) the connectors were perhaps dirty or something because I scrubbed them with tissue and finally got it to fire. I hope that doesn't mean my flash port is on the way out!

[Sunny Valentine]

With the Canon ETTL flash system in P mode the camera assumes you want the flash to dominate the exposure. So the shutter speed is chosen from between 1/60 to 1/250, and the aperture and flash power are set to have the flash part of the exposure dominate the picture. Depending on available light you might see very dark backgrounds.

In A (and S) modes the camera and flash attempts to provide a balance between flash exposure and available light. In case you want the flash part to dominate the picture, you can adjust the flash exposure on Camera. Putting this to (+) will shift the balance towards the flash, the other way round the overall light will be dominating.

This is the mode for shadow fills, and such.

In "M" mode you set the overall exposure by choosing the Aperture and Shutter speed, and then the flash kicks in, and fills the shadows (or more) automatically. Again, you can adjust with Flash Compensation here.

You can also turn off the TTL automatic and use M mode with manual flash power. That gives you the most options to tune the picture as you see fit.

Hope that helps!

[Pooklook]

I have had the flash lock up a couple of times on several canon models.

I took the battery out to the camera and the flash and put them back in

and that seemed to solve it. Be sure to check the canon website for any

firmware updates that may be available for your camera.