I have been a Nikon D40 owner for a couple of years. I have not had any problems with the Camera, until yesterday.
I can only take pictures when I have the AE-L/AE-F button pressed and then the main shutter button pressed at virtually the same time. I also no longer receive the beep and the auto-focus does not work. I have been through all the options in the manual, and have resent the camera back to basic settings. The top wheel is set to "Auto". Unfortunately none of this has helped with the basic problem. The camera was working fine last week. I can't see any reason for the sudden change.
Any help you can give on this matter would be appreciated, as it has been a good camera.
#2. "RE: Nikon D40 Problem" In response to Reply # 0
Thank you for your response. That is what I thought too. So I checked the manual, and then checked the camera.
AE/AF Lock is set to ON
AE Lock is set too Off.
It is just really strange, as far as I know no one has messed around with the settings, but the camera will not work without the AE-l /AE-F button pressed, and the main shutter button with about 0.50 seconds.
#3. "RE: Nikon D40 Problem" In response to Reply # 2
I think you have confirmed that the above suggestion was correct, but that you have understood neither it nor that page in the manual!
The item (12?) on the 'pencil menu' does not set the camera mode: it customises the action the camera takes when you press the AE-L/AF_L button (under your right thumb).
The button normally locks exposure AE, focus AF or both. 'AE-lock hold' makes it 'sticky' - repeated presses lock and unlock the exposure.
Selecting 'AF-ON' does not turn AF on ! It customises the button so that the button causes the camera to focus when it is pressed. Naturally this means that AF is off until the button is pressed (and after it is released) !
It seems to work with all the AF modes on 'Pencil menu > 2 Focus Mode'.
It is easy to see why you find the menu confusing - I haven't seen the manual, but it probably loses some clarity in translation.
Why would you want to trigger autofocus manually ? Creative blur ? Prefocus on a point on the road, and shoot when a car hits that spot ?
Actually the main use is as a 'focus trap', which removes the human element of precision shutter timing. 'AF-ON' also disables the shutter release (as you noticed?). When you half-depress it, it sets the exposure as usual, but the shutter doesn't trip immediately (unless something is already in focus). If you keep the shutter button pressed, the camera waits until it detects something in focus, then shoots ! It can be useful for sports, wildlife, insects in flight etc ! Not so useful if you enable it by accident, though.
You can use it to throw the depth-of-field entirely behind or in front of the sensed point. Just approach focus by starting too near and moving back, or vice-versa.
I had hoped it would enable focus-trapping with old manual lenses (Nikon F !) but no joy. Although the viewfinder indicator will confirm focus, without the electronics in the lens it doesn't de-couple the shutter from its button. It seems to be a fortuitous feature, rather than well-thought-out.
I vaguely remember someone modifying old lenses to fool the camera, adding electronic chips and contacts ! Does anyone remember this ? Sourcing spare parts or broken lenses coud be tricky.