abnormally slow autofocus on a new kit lens?

[pixeltarian]

I just got a canon T3i and wanted to shoot this to a photographic community to see if there is a solution I can do myself before having to ship the whole thing out for repair. Basically my zoom lens seems confused and takes a long time to focus.

I have just a run-of-the-mill kit lens (EFS 18-55). I'm going to try to describe in words how the autofocus works. the more "o" you see the longer the zoom ring is traveling (so to speak) and "..." means there is a pause for a little bit. So I press the shutter release half way down to focus and...

zoooooooooooooooooom (in one direction and then, oops went too far)
zooooooooooom (in the other direction, but over compensated)
...
zoom zoom zoom zoom zoom zoom (lots of little quick zoom to try to make sense of it all)
...
zoom zoom zoom (almost in focus)
...
zoom zoom (now more or less in focus, sometimes not perfect though)
...
...
"ready to shoot" beep


so at first just thought that it might be because this is the cheapest zoom lens canon puts out, but then I tried the exact same lens from my friends old XSi and it's more like:

zoooooom
ready to shoot.


And I didn't change a single setting on the camera so it's got to be the lens. Anyone ever run into this issue? is this just a janky lens I need to send back? Are there any fix-it-from-home strategies I can look into? I don't want to go without a lens. I broke the bank to buy this thing and need it for work every day.


Oh, and also - this is my first post! So allow me to introduce myself:

hello I'm Jeffrey James. I have used many cameras over the years but never owned a decent one myself till a couple weeks ago. In the realm of snapping photos: I like making the reality we take for granted look interesting enough to consider and trying to evoke that emotion that everything is amazing when you really focus on it.

I also want to start making videos mostly tutorials at first but I have a few filmmaker friends and have been in a few shorts.

I know a lot about audio and went to school for audio engineering. I know a little about lighting, but probably not nearly as much as any serious photographer. If you have any questions for me about anything and feel like I might be able to help, feel free to ask! I love talking about stuff, especially audio.

 

[Ewinter]

Hi Pixeltarian, Welcome to the CR forums.
Firstly, what lighting conditions were you testing in? does it still do this in broad daylight? which autofocus point are you using?
And more than that, did you buy it new? if you did, the store should be able to swap out the lens for you if it's demonstrably faulty

 

[dr croubie]

There's three ways that my camera emulates this scenario:

Using live-view. It's incredibly slow to autofocus, so I use the viewfinder as much as possible.
Too dark, or no contrast. Shooting all one-colour objects, or when the lighting isn't that good.
Using extension tubes, or teleconverters. Can confuse the autofocus, reduce the amount of light, etc.

So, you don't sound like you're using teleconverters or extension tubes, so we'll rule that out.
Go outside in the sun, point at a tree or brick wall or something, use the viewfinder.
Or even just get some white paper and draw some lines on it with a black texta and point at that. If it is still as slow as before, i call borken, get it fixed.

 

[Mt Spokane Photography]

Bad lens, send it back to wherever it came from.

 

[Ryan708]

It does kinda sound like live-view was enabled?