This camera is supposed to auto focus, but lately it hasn't been. When I zoom into something with an intricate pattern, the camera will not pick it up because it won't focus. What do I do?

That's the backfocus problem. Take your camera to a Sony service.
If the lenses are ok, they will do an adjustment. If the lenses are defective, they will
replace the lenses, but that costs much.

if other auto-focus lenses work, then it is likely that this particular lens has a defect I suggest you send it in to Nikon for servicing

Make sure both the lens and the camera are switched to af (auto focus). If that doesn't work remove the lens and replace it to make sure it is mounted properly. You can also check the camera with a different lens to make sure it isn't a problem with the settings on the camera. If all of that fails take it to a camera or electronics store that does service work to make sure it hasn't been damaged.

Samsung pl201 the zoom isn't working and stopping the camera from working normally. it says to take out the battery and try again. this hasn't worked.

Is there also an AF / MF switch on the camera body ?

The F/stop isn't supposed to change when you focus. Depending on the camera, you change the f/stop by either turning the aperture ring on the lens or turning a command dial on the camera body.

change auto focus to single focus mode,
since it is on continuous auto focus on default, it would focus all the time so you don't need to click half way before taking a picture

there is something wrong with the zoom and focus electronics, mine won't focus in wide angle, it's permently focused on 3x zoom.

Try to push the shutter button half way down first so the camera will auto focus first. You should hear the lens move to focus, then press it the rest of the way down to take the picture. Your pictures should be much better quality if you do it this way.

Way to check settings is to take the batteries out for a while, it should revert to factory default settings. I tell a lot of People to try this, it works an amazing number of times. Auto focus looks for vertical lines, what are You shooting at? Try rotating the camera 90 degrees, if it locks better,Bingo. Subjects without much contrast are hard to lock focus on