Lens problem Help

[johnoz]

Hi all,
I wonder if you can shed any light on a problem! my son has a EF24-85USM kit lens.
It has developed a fault, the auto focus will not lock on? it keeps hunting on a subject to focus!
Though having said that it will focus on some things first time.
Question is, is it broken in some way? can it be fixed? what sort of cost would be involved?

We have tried the lens on another body and it reacts in the same way.
Seeing that its not an expensive lens, is it just worth replacing!

Thanks for reading.

 

[Alastair]

It could be a lens issue, but 9/10 times it's a user issue - either a setting isn't right for the circumstances or the user has moved into a new area of photography less suitable for their familiar choice of settings.

But you've really only provided a fraction of the useful information but you've hinted at all sorts of relevant details that we can't know unless you tell us.. ..
- What sort of subjects does it fail to focus on?
- Under what conditions does it fail to focus?
- What bodies have you tried it on?
- What focus modes have you tried?
- When it does focus, what sort of subject and under what circumstances is it being used?

 

[johnoz]

It could be a lens issue, but 9/10 times it's a user issue - either a setting isn't right for the circumstances or the user has moved into a new area of photography less suitable for their familiar choice of settings.

But you've really only provided a fraction of the useful information but you've hinted at all sorts of relevant details that we can't know unless you tell us.. ..
- What sort of subjects does it fail to focus on?
- Under what conditions does it fail to focus?
- What bodies have you tried it on?
- What focus modes have you tried?
- When it does focus, what sort of subject and under what circumstances is it being used?

I can assure you its not user error! it has worked fine till now.
In answer to your questions...
Don't seem to focus on any thing! if you try to focus on a window cill the centre point will hunt in and out continually until it focuses, sometimes it will beep and lock on in focus and sometimes out on focus!
Have tried in 2 separate 40D bodes
Tried it in all modes P TV etc
Tried AI focus, one shot, AI servo all no joy
Not sure on the last question? is all i know is it just keeps hunting in and out truing to focus!
He has a EFS 60mm that works as it should, point, half press, focus, click, picture.

So end of the day i think its broke :-(

 

[kendo1]

Clean the contacts?
Worth a try before you bin it

 

[Alastair]

Not sure on the last question? is all i know is it just keeps hunting in and out truing to focus!

Just wondering if there was a pattern to the observation you made in the first post..

Though having said that it will focus on some things first time.

Sounds like time for a new lens..

 

[Box Brownie]

Clean the contacts?
Worth a try before you bin it

+1 ^^^

 

[johnoz]

Thanks, that was what i was thinking, as i wondered if repair costs outweigh buying a new one.

 

[StewartR]

Don't seem to focus on any thing!

Well, OK, but...

if you try to focus on a window cill the centre point will hunt in and out continually until it focuses, sometimes it will beep and lock on in focus and sometimes out on focus!

You see, that's the kind of data that makes people question whether it's user error. If you're trying to focus on a window cill, that raises three possibilities:
1. It's an inherently low-contrast target so there might be nothing for the AF to lock onto.
2. If you're indoors you might be closer than the lens's minimum focus distance.
3. If you're indoors the light might be poor.

Perhaps none of them are the case, but you haven't ruled them out, and your choice of target suggests that you weren't aware of these issues.

So - get outdoors, in bright daylight, and use the number plates of stationary cars as targets. Make sure the plates aren't in shadow. Test the AF at different ranges from MFD to as far away as you can, and report back. If your lens really does have a problem, this will prove it.

PS Don't forget to clean the contacts - on both the lens and the camera - first!