I have been in video for the past 12 years and I am now getting into photography. I just bought a Canon 30D but I have one big problem. I cannot get the foreground and background in focus. I am primarily using a 28-135mm with Image Stabilization. I tried an aperature of f/22 because I thought a smaller opening would increase the depth of field. I didn't seem to work. I also tried the A-Dep setting but still didn't work. I don't know if the lens is the problem or my technique. Could someone tell me exactly what I need to do? I am really getting into doing weddings and I have seen shots at the church where the bridal party is lined up on the altar and everything (even the back of the altar) is in focus.
You need to select a point of focus 1/3 of the way into the scene, lock it in and then fire the shutter.Usually one holds the shutter 1/2 way down to lock focus, then recompose the shot and then push the shutter release all the way in. You can also focus manually and not have to hold the cutton in and recompose; I find this handier than auto focus when the camera is on a tripod. If the camera has a depth of field preview you can tell what part of the scene will be in focus before you take the picture.
You're running into two different issues.
The first is that the autofocus always locks into the closest object within the range of the focus point you are using. In the viewfinder, choose a different focus point to center the most important point in your composition.
The second issue is that you are not using a lens wide enough to give you the depth of field you require. The 28mm end of the zoom is only a 44mm equivelent lens which won't give you near the depth of field that a wider lens will get you. I recommend one of the 12mm-24mm zooms, or at a minimum a 20mm lens.
I've transferred the autofocus function to the AE lock button on my Pentax cameras. I lock in the focus with the AE button, then the camera doesn't refocus when I trip the shutter. Works great but takes some getting used to. I'm sure the same is possible with Canon and Nikon.