Auto focus My shot is composed and I half-depress the shutter release and the lens focuses on what I want, then, before I can take the shot, the lens has focused again (usually blurring what I wanted it to focus on). All the time the Ultra Sonic motor is humming. Help!

Because that's the way it was built. My Sony cybershot does the same.

Does this problem still exist when you have the shutter pressed halfway down?

Regards,
Worldvet

Most camera's, and the Olympus to work the same with auto focus. You place the AF target o the place you want to focus on. (the part that should be in focus in your picture) then press the shutter release button half and wait tip the AF conformation mark lighter up on the view finder. (the little round in on the bottom left) Then frame the picture as you want it shot and press the button complete.
I'm not sure your lens has a AF / MF switch, but that should be on AF all the time.
When you use non AF lenses, your cmarea can't focus automatically.
It should work fine with the kit lens. (lens that was originally delivered with the body)

The r11 is in the lower right of the top LCD or view finder that is in the D80 manual page 36 it speaks about the buffer. The r with a number is how many shots the buffer at that moment can handle. It is not an error message. For auto focus issue is the lens in AF as well as the camera?

Hard to pinpoint the exact problem...
What lens do you have attached? Does it have a switch for M/A and M (auto focus/manual focus)? If it does ensure the switch is in the M/A or Auto Focus position.

On the left side of the camera on the face there are 3 positions, C, S, and M. Ensure it is not on "M" for manual.

Do you have your camera setup to only allow the shutter to operate when it is in focus?

problem in lens censer replace it

Check if you have any of following issues
1. Lens is not AF or AF-S
2. Try flicking the lens switch from A to M and back to A again, might solve any contact issues
3. In the menu system also you can navigate to select the manual or auto focussing. if this got set to 'Manual' mode by mistake the camera will not autofocus even if the lens switch is in Auto mode.

Only reason the lens will not auto focus when you depress the shutter half way is due to either lens AF switch is set to Manual OR camera body's focus system is on M. There is 3 way toggle switch below the synch port around the lens mount. It should be set to C or S in order for auto focus to work. If all the settings are correct and even "AF-ON", next to rear dial doesn't activate auto focus then the issue maybe in the setting or the body itself. As for the buffer reading r27, I think mine displays r## regardless of burst/continuous mode.

• Make sure both lens and body are set for autofocus. There are two switches near each other with "AF" and "M" settings.
• Check the camera's focusing settings, or do a factory reset (from menu) to 'start over'. Usually helps to have AF-Assist on.
• Try setting the AE/AF-lock button (upper rear, near right thumb when holding camera) to turn on AF. The camera may respond better to this than half-pressing the shutter release.
• Make sure the lens is fully attached to the camera. You shouldn't be able to rotate the lens without depressing the lens release button, and you should be able see a tight seal between the two.
  

the auto focus works on the basis of contrast. If you aim your chosen auto focus square at an item that fills that square with only one color or shade of color light a blank wall or a solid blue sky the camera can't focus because it is trying to compare the contrast in order to focus the camera. try to make sure that you choose an item with contrast to aim your auto focus square on like someones eye and part of their cheek so the camera can see somre contrast to evaluate then focus. Obviously you depress your shutter half way to activate the auto focus let the camera do its thing keeping the shutter half way depressed move your field of vision to where you want it then fully depress the shutter to take the picture. the camera relys on seeing some contrast within your autofocus square in order to auto focus