help with a 420ex flash not working right...

Hi all, I still have to clean the contacts and such on both the shoe and the flash, but I was hoping for some of your opinions. I have a Canon 7D and tonight, I was shooting in Aperture priority mode with the kit lens at 3.5 with the flash on. The flash was ready, but was not going off. So I took the unit off, remounted it, and the flash now goes off (obvious bad connection) so now that the flash is flashing, I am noticing my shutter speeds are the same with or without the flash full on blast (1.5" exposure at f 3.5). If I put the camera in full auto mode with the flash on, shutter speeds of .5 I am wondering if my flash unit is going kaput, or what might be the problem. Been gnawing at me for a bit, and wanted some professional help

Thanks in advance...

Keith

I have a 7D and a 420ex. I haven't had any problems with the 420 before, but I haven't used it much, since I got my 580ex II. I'll play around with it and see.

When your camera is in AV mode the meter is still going to measure ambient light levels. It cannot figure in light that has not been produced yet. IE: the flash. So the SS is going to be the same or very close with or without the flash mounted. This is why most use manual mode on the camera when using flash.

Thanks guys. I was not kind of figuring that Dale. I don't shoot flash very often, so when I do, I forget some of these things. Almost thought it would be an excuse to get a new one I will keep playing around with it. Thanks again

I have the 7D and both a 420ex and the 580ex. I have not tried using the 420ex mounted on the camera but have used it off camera and controlled by the popup flash. That works pretty good but I have only tried this indoors. I set the camera in manual mode with a SS of 160 to 250 depending on how much ambient light I want to capture and use an aperture of around 5.6. Then I use flash exposure comp to adjust the amount of flash. This is the only way I know to control the 420 since it is eTTL only and cannot be placed in manual mode.