Digital camera lenses focus keep blur all the shots?

I have two lenses. One makes perfect pictures in sharp focus. The other one - screws all the shots making them blurry. Even in viewfinder I can't make the picture look sharp neither on Auto nor on Manula focus. This is a telefoto lense.

Any help???

p.s. forgot to say - it happens both with a tripod and without it :(

well .. maybe this is a stupid answer ! are you sure your lens are clean?! because some times even if the dirt so small the camera focus on it and blur the target! no matter what kind of dirt finger print or whatever.

You need a new lense.

It sounds like your lens is toast (damaged/broken). Don't use it any more.

You can have a repair place look at it, but they may charge you just for an estimate. It depends on whether or not they can find the damage without disassembling the lens.

Make sure the autofocus switch is set to AF and not MF. If it is on AF, then test the lens by taking three objects and placing them at a 45 degree angle about a few feet apart on a table. Focus on the middle object and then look at the photo. If the front item is in focus, than the lens is "front focusing" and if the back item is in focus, it is "back focusing". If this is the case, you will need to send your lens in to a service center to be calibrated.

I would check the back element for grease or solid smudge. Many people obsess over the front element being clean when a lot of the dust and grime is on the back. That is where I would start.

Because you are using a lens at 300mm would cause a camera shaking,you have to used professional tripod,so that it won't get blur all the shots.

It sounds like the lens is defective. Could be the contacts are faulty of the chip in the lens that tells the camera the distance to focus is out of whack. Also, it is possible the lens needs calibrated.