Is my lens knackered?

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polsonm87

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Hi all,

My standard 18-55mm Lans on my Canon 550D wont AutoFocus when in Manual, is this the lens or have a got a setting wrong?

Any help would be great.
Thanks
 
Wont auto focus in manual mode? or in manual focus?? I presume you mean in Manual mode: does it focus ok in other modes? Aperture/shutter priority for example?
 
Manual on the control dial
sorry forgot to say

It wil focus then when you press the shutter it just defocus'
 
polsonm87 said:
Manual on the control dial
sorry forgot to say

It wil focus then when you press the shutter it just defocus'
Click to expand...

So it will focus then?
 
Yes but it will not take a picture, was out lastnight with a mate who had the same setup and settings and hes was managing to take pictures no problem whilst mine just kept focus the defocusing when i tried to take the shot
AutoFocus work on Av and Tv
 
It sounds as if its simply not locking focus. It would do this in low light or if the subject it too close for example.

Does this happen in low light or all the time?
 
There just isn't enough light on the subject to attain focus, simple as that.


When you are focusing, make sure you focus on a contrasty edge, a block of black or white, you will never get focus, there needs to be some variation or pattern for the focus to lock.
 
Yea, just strange that my mates camera was Autofocusing no problem
il try again tonight and see
cheers
 
polsonm87 said:
Yea, just strange that my mates camera was Autofocusing no problem
il try again tonight and see
cheers
Click to expand...

Maybe his camera has slightly more sensitive focal points, or he was using correct low light focus technique? Or using a lens with a wider aperture so it was gathering more light.. So many variables its not a fair comparison.
 
He has the same camera but he possibly had a different lens on, i understand where you are coming from.
It was very dark to be fair

Thanks again
 
You need to focus on something with contrast, if you just try and focus on something black you will have a bad time. Try again in a lit room to focus on something.
 
Mystery57 said:
A mate of mine had a similar problem with his kit lens and a 450d camera - it wasnt light that caused the problem, the lens was a bit iffy, as manually turning the focus on the lens and or switching the camera on and off a few times usually got it working again.
Click to expand...

By the sound of it though, I think it's a low light / contrast issue rather than a problem with his lens.
 
This issue is quite common when focusing at night, I had it last week and in the end opened up the aperture as wide as possible and focused manually and then did what I needed to do, the auto-focus can get confused if theres no clear difference in textures. E.g. I found it really difficult to focus on tree branches when it was late at night, no big deal as it was to be expected but I just needed to focus manually.With a low aperture you might not be able to see as well so open it up as wide as possible and focus though that, then make the necessary ISO, shutter and aperture adjustments.
 
A similar thing happened to my mate's 18-55 on nikon. For some reason there's a bit of play in the mount and unless he 'screws' it in completely it doesn't focus.

Hope this helps
 
Thrash said:
This issue is quite common when focusing at night, I had it last week and in the end opened up the aperture as wide as possible and focused manually and then did what I needed to do, the auto-focus can get confused if theres no clear difference in textures. E.g. I found it really difficult to focus on tree branches when it was late at night, no big deal as it was to be expected but I just needed to focus manually.With a low aperture you might not be able to see as well so open it up as wide as possible and focus though that, then make the necessary ISO, shutter and aperture adjustments.
Click to expand...

The lens is wide open until you press the shutter button. It will make no difference changing it in the camera.
Unless of course you are using an old manual aperture lens...
 
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