18-55mm Lens don't autofocus between 20-40mm

[RafaelNuno]

Good afternoon,

I have a Canon 18-55mm Lens and it just started to fail the autofocus system between +/- 20 to 40mm... It doesn't make any sound (it even try to focus, don't move), simply show the 9 focus point blinking in red! If I put it at minimum 18mm autofocus normaly/perfectly and if I zoom in to >40mm autofocus normaly too!

Any suggestion or idea?

Thanks,

 Rafael

[Waddizzle]

Make sure you are not too close for the lens, and that the ambient light is not too dim for the camera.

If you go outside on a sunny day, with the camera in Green [A] mode, the camera and lens should "behave" properly.  If you are still having problems under those conditions, then I suggest that you contact Canon Support.  

BTW, most versions of the lens are so inexpensive, that a repair would cost more than a new one.

[AndyMilnePhotog]

I have a Canon 18-55mm Lens and it just started to fail the autofocus system between +/- 20 to 30mm... It doesn't make any sound(it even try to focus, don't move), simply show the 9 focus point blinking in red! If I put it at minimum 18mm autofocus normaly/perfectly and if I zoom in to >30mm autofocus normaly too!

Hmm... this is a bit puzzling. 

What I would do is put the camera (I assume you have a Rebel) on a tripod or flat surface. Then for comparsion, take a high-contrast & well lit test picture using manual focus @ 24mm until the subject is in focus using Live View (LCD Screen). Then take the same picture using the viewfinder or Live View w/AF at the same focal length & see if the lens focuses properly.

If the two pictures are equally sharp, then it is simply user error and are limitations from the lens.

If the manually focused picture is sharper than the AF picture, then you may have a defective AF motor & I would call Canon Cusomer Service about the issue you mentioned.

[RafaelNuno]

Waddizzle Thanks for the comment but I'm a "semi-professional" photographer and I use the 600D with this lens for like 5/6 years (not much often, but still 5 or 6 years)! Of course I know that I cannot have something too close or be in dark environment to take the picture... and before I post this message, I've searched everything about this most common lens fails. But that one failing focus only at 20-40mm, is the first situation I've seen...
Imagine: In the same spot if I put it in 18mm, it focus well. If I zoom it JUST to 20mm, don't focus. In 40mm, don't focus. If I put it up to 45mm, starts to focus again! Really strange...

[RafaelNuno]

AndyMilnePhotog Thanks, and I will try it, but that's not really a solution =/
I've done the test: the lens don't autofocus between 20 to 40mm, only! In 18mm or 45-55mm it focus perfectly!