Focus trouble

Hello,
I have a Sigma 18-125mm lens for my Nikon D100 for a week now and have
encountered a problem with the autofocus. When I try to focus at 18 mm on a
very distant object (distance: infinite) the d100 doesn't focus (the lamp
inside the viewfinder doesn't light up) and the lens is making a sound as if
it couldn't focus. When i then put the D100 to M, the focus ring is stuck, I
can't move it around anymore, unless, I put it back to S and focus an object
that is close.

When the problem occurs, the zoom ring can be turned around more difficult
from the 18 to 24 position and then it turns quite normal. When I take the
lens off and on again, the zoom ring turns around without any problem unless
I focus at 18mm a very distant object.

Has anyone had this type of problem yet ? I had the same problem with a
Sigma 18-35 mm a year ago, thought the problem was the lens, so I sold it
again. I also tried the lens on a friends D100, there it worked without any
problem. So I guess, the problem is with the body, not the lens.

Thanks in advance for any help !

In article , Luc Brentener
wrote:

Hello,
I have a Sigma 18-125mm lens for my Nikon D100 for a week now and have
encountered a problem with the autofocus. When I try to focus at 18 mm on a
very distant object (distance: infinite) the d100 doesn't focus (the lamp
inside the viewfinder doesn't light up) and the lens is making a sound as if
it couldn't focus. When i then put the D100 to M, the focus ring is stuck, I
can't move it around anymore, unless, I put it back to S and focus an object
that is close.

When the problem occurs, the zoom ring can be turned around more difficult
from the 18 to 24 position and then it turns quite normal. When I take the
lens off and on again, the zoom ring turns around without any problem unless
I focus at 18mm a very distant object.

Has anyone had this type of problem yet ? I had the same problem with a
Sigma 18-35 mm a year ago, thought the problem was the lens, so I sold it
again. I also tried the lens on a friends D100, there it worked without any
problem. So I guess, the problem is with the body, not the lens.

Problems with a Sigma product? It's obviously PEBCAK.

In article , Luc Brentener
wrote:

Hello,
I have a Sigma 18-125mm lens for my Nikon D100 for a week now and have
encountered a problem with the autofocus. When I try to focus at 18 mm on a
very distant object (distance: infinite) the d100 doesn't focus (the lamp
inside the viewfinder doesn't light up) and the lens is making a sound as if
it couldn't focus. When i then put the D100 to M, the focus ring is stuck, I
can't move it around anymore, unless, I put it back to S and focus an object
that is close.

When the problem occurs, the zoom ring can be turned around more difficult
from the 18 to 24 position and then it turns quite normal. When I take the
lens off and on again, the zoom ring turns around without any problem unless
I focus at 18mm a very distant object.

Has anyone had this type of problem yet ? I had the same problem with a
Sigma 18-35 mm a year ago, thought the problem was the lens, so I sold it
again. I also tried the lens on a friends D100, there it worked without any
problem. So I guess, the problem is with the body, not the lens.

Problems with a Sigma product? It's obviously PEBCAK.