Canon Lens Problem (1 Viewer)

[ohlookabirdie]

My friend's Canon Zoom Lens EF-S 18-55mm 1:3.5-5.6 IS has a problem.

i use the same lens but not the IS version.

Before i explain the problem, i'll tell you that the camera body is not the problem as i have tested it on mine (its the same model EOS 450D) andi tested my lens on hers. the problem is definatly with the lens. it has a Jessops UV filter on it.

It has 2 problems actually.

One is that the filter wont come off. she got it with the filter already attached and it has never been off. I was bought Second hand from amazon UK (she thinks) a few months ago.

The other is that when on auto-focus it is having trouble focusing. it seems to me (i've been using the same camera for almost 4 years) that it is trying to focus on a smudge on the inside surface of the filter. I have cleaned the outside surface with no effect.

when i use manual focus to unfocus it, then switch back to auto it can focus on the first thing it is pointed and take the shot, but any further attempts to focus fail and the auto focus confirmation light flashes and the shutter wont fire until i unfocus it again on manual.

i think that is all the details. a speedy reply would be much appriciated as she is leaving for another country tomorrow morning and i wont be able to help her fix it then.

 

[tdodd]

To remove the filter, if normal grabbing and twisting won't work, get a rubber washing up glove and lay it flat on a firm surface such as a kitchen worktop. Then press the front of the filter flat onto the glove and try untwisting it. This will give lots of grip upon the filter but will avoid the deformation which can occur when trying too hard to squeeze it between fingers for removal.

Another option, which has worked well for me with a stuck CPL is to get a piece of flat (2 wire) mains flex and loop it around the filter, pinching it tight where it meets to create an even circle of flex around the filter. Once again this should form a strong grip upon the filter, but spread the load evenly around all sides so that it does not deform.

There is an example of the mains flex trick in this post - http://photography-on-the.net/forum/showpost.php?p=4806850&postcount=17


Once you have the filter off you can then check whether the AF still has a problem.

 

[ohlookabirdie]

got the filter off using a jam jar lid remover...

still got the AF problem

any suggestions? or self repair options?

 

[ohlookabirdie]

the little red HUD lights that usually indicates that its in focus flash when its attempting to focus but it still isnt achieving focus. i can here the motor moving for an instant and then nothing. its as if its giving up