When I take a picture on my nikon, why is something upclose so blurry, but far away clear?

I own a Nikon D5100. And when I press the shutter button halfway it doesn't try to focus anymore like it used to, it worked fine last night, and I tried going in the daylight for better lighting and its still doesn't work. The switch on the lenses with the A and M its set to A BTW.

Your 'focus' settings "need" to be adjusted!
Sweetheart.

Sounds like the problem is that you have no idea how to use a DSLR camera properly. But hey, don't worry, you still look like a professional when you carry that big black cameras around right?

It is possible your lens is not focusing. If you are using the minimum aperture, say f/22, and a short focal length, such as 18mm, then a large part of the photo may be in focus regardless of the focus setting.

Also, make sure the focus mode (page 40 in your manual) is not set to manual focus. This is not the A/M switch on the lens, but in the menu system in your camera.

Try this:

Put the lens cap on, then depress the shutter half-way. This should force the lens to "hunt", and the focus to go from stop-to-stop. If this is happening, then the camera focus is working fine.

If the lens doesn't hunt with the lens cap on, you might have a problem with either the camera or lens. The first thing I'd do is to clean the electrical contacts on the lens and camera body. You are gonna have to break out the manual to make sure you do that correctly.

It is called depth of field.

Each lens has its own depth of field features.

The wider the lens, the more the apparent depth of field

The longer the lens, the shallower the depth of field

By changing the lenses apertures, you can increase and decrease the depth of field within the range of the camera

When you are using the lens in A, auto-focus, the camera automatically focuses the image. In the M, manual focus mode, you have to focus the lens using the electronic rangefinder in the viewfinder.

It's probably the depth of field, check out those site to learn more about it:

http://www.dofmaster.com/dofjs.html

http://www.cambridgeincolour.com/...-field.htm

Let the lens on A (auto focus), M (manuel focus).

If the camera body is set to A (it mean it's priority Aperture), therefore you need to adjust the aperture f/? Manually via the camera.

There's such a thing called minimum focusing distance. Your subject is nearer than that.

It could be the lens.

Every lens has a MFD (minimum focus distance) where you can only get so close to an object and have it stay in focus.

Go ahead and focus on an object close to you, move closer and it should get out of focus, move back and it should get back into focus. Do this without refocusing.

*EDIT*

What do you mean by upclose and far away?

Is this in the same picture? The object is blurry but what's behind it is in focus?

Or when you try to take a picture of something close to you, it comes out blurry and when you try to take a picture of something far from you, it's in focus?