Canon 50D Shutter Delay Problem

Hi everyone
I hope someone can help me with a problem with my 50D Shutter delay. I have already sent my 50D to the Canon factiory for a fix for this but they said my camera was performing to the factory specs. I have set my camera to the settings that Artie sent out for the 50D. This was happening before those settings but still continues as per this am.
Camera is set to AWB, Auto ISO, Av mode, f/4.5, Canon 100-400 L lens and I am still havinmg a problem. Here is what happens. When I am pushing the shutter to take an image, there is a delay in the time after I push it and the time it takes a picture. I can prefocus and it still happens. It does this in A1 Focus, A1 Servo, Center focus and all focus points. I mean there is a delay to the point that I am missing images that should be taken as you can push the shutter button and it will not take the image, then all of a sudden it will fire the shutter. This is quite annoying and troublesome and as far as I am concerned this should not be happening. Today it was cloudy and dull lighting but it seems to happen under all lighting conditions.
I tried different lenses this am using a Canon 70-300 f/4-5.6 IS and a 70-200 f/4L lens. These lenses showed no delays at all and take images instantanious. This is my wifes camera and she said it has been happening to her for quite a while.
Does anyone have any idea what could be wrong with camera or my settings?

Hi Bill Have you tried without the AF? Just wondering. Would try using another 50D for a direct comparison. Doesn't sound right !!

Hi Alfred,
No I have not tried it without AF. Let me also say that a friend was shooting right beside me today and had a 50D also and hers started acting the same way. We were focusing on pelicans and the background was similar so I was wondering if that may have caused it. Low light was possible th cause but the camera is useless if it continues to act up.

Bill,
Set your camera to manual focus and retry, it should fire rapidly. If this is the case the lag is because camera is unable to lock focus. If there is a lag even in MF mode then there is something wrong with the body.

Bill,
Set the ISO to 400. Your current settings are asking the camera to choose an ISO, shutter speed, and AF. Does this help?

Thanks Don, I tried that and set ISO to 400 and WB to sunlight and it seemed to work fine for a quick test. I will test it out better as soon as I am out again.
Thanks,
Bill

Bill shooting into the water can cause the AF problems (glare)

Thanks Al, that could be a lot of the cause too.

A suggestion for AF setting: use either AI Servo or One Shot (depending upon moving or stationary subjects). AI Focus is a hybrid mode and asks the camera to choose between AI Servo or One Shot and your camera does not know if you are photographing a moving or stationary subject. So take control of your camera and choose between either AI Servo or One Shot.

You probably already knew this, but just in case.

The 50D is a very powerful camera with many choices and great flexibility. I'm learning as much as possible on how to optimize mine. I found a book on the 50D - "David Busch's Guide to the Canon EOS 50D" and it goes into excellent explanations of settings and why to use specific settings for certain situations. It is much more in depth than the Magic Lantern Guide book and the Canon manual. This book is directed at Intermediate to Advanced users. I got mine at a Barnes & Noble.

Thanks Don, good points and thanks for the book info. I think I had heard that from another photographer but do not know if it was the same or not.