Is it possible that the flash doesn't correctly expose and autosets the shutterspeed when shooting in Av?
Example:

If i'm shooting f4 at iso 100 on auto mode the shutter speed will be 1/60(with a 50 mm focal) the flash here is working, i mean the camera reads the flash and compensate the shutter speed.
If i'm shooting f4 at iso 100 on Av mode(same stuff but on Av mode) the shutter speed is like 1/18 what the fuck?

From what i've learned i can only shoot manual and full auto with the 580 ex ii?

I had an sb-900 when i still had the d300s and it perfectly worked on aperture priority mode.
I've googled and i'm not the only one surprised for this.
Am i a retard or what?

This post was edited by Verdena on Mar 22 2011 04:42am

The flash doesn't change the shutter speed, but in ETTL mode it will try to compensate to give you a correct exposure. As a general rule you should shoot in M with a flash. The flash will give you the ability to shoot at faster shutter speeds but will not change the shutter speed for you - for example, in your scenario number two the settings would be the same with or without flash because the camera is exposing for the current scene. If you want 1/100 on your shutter speed instead, you have to dial that in yourself in M. When you take the picture (in ETTL mode) the flash will try to give the correct power to get you to 1/100.

One thing you can do is use the DOF preview button - while your flash is plugged in, this button will make the flash do a "modeling light" which basically makes the flash strobe for a few seconds so the camera can get an exposure for what the photo will actually be when the flash goes off. I find this almost useless though, you're better off just using M and getting a feel for what your settings need to be.

This post was edited by bergmann on Mar 22 2011 06:10am

I was just pointing out that the fact the flash gives me the correct shutter speed in auto and not in aperture priority is really stupid.
I know that i can shoot in M.. but makes no sense that i can shoot in auto and not in Av.

Um, first of all, Andrea, why would you even permit the camera to shoot at iso 100 + shutter speed 1/60? The580 II is easily powerful enough to let you shoot 125+, thus resulting in a sharper image. Methinks you need to realize that the auto modes suck.

I know the automodes suck lol.

I vote for dumb user

Maybe, who knows.
Fact is you can not use the flash with priority modes.

Go back to Nikon.

haha this.

i use flash(580 II) in AV mode pretty much all the time and it works just fine. AV exposures based on the room light whether you got flash on or not. the reason to use AV(or other auto modes) with flash is the get some of the room light on the exposure also, no wonder you got too long shutter speed if you use 100 iso and too small aperture in too low light. if you use AV with exposure set to 0 and flash exposure set to 0, no wonder you get weird exposures. if you want good exposures that has the light from environment and light from the flash, set the exposure from camera to somewhere around -3 to -1(depending on situation) and flash to -1 to 0. if you want light only from flash to show, only then use low iso in manual mode and other settings in camera so that you dont get any environmental light in the exposure..

This is just stupid and totally different from nikon's aperture priority.