Olympus UK E-System User Group

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-   -   HELP! 70-300 autofocus problems. (https://e-group.uk.net/forum/showthread.php?t=21251)

Batman 21st June 2012 03:09 PM

70-300 autofocus problems.
 
I only seem to turn up here when I am needing advice. I'm sorry for that. I can only put it down to lack of time.

A couple of years ago I had a very embarrasing situation when I thought the autofocus on my 70-300 lens had failed. In fact it was me and the little switch on the lens.

This time it has actually started to misbehave. Manual focus also seems a bit 'sticky'. In autofocus it 'hunts' for 2-3 seconds, sometimes much longer, before confirming focus. I have tried cleaning the contacts and the behaviour is the same on both my E-520 and my E-30. The lens is now 4 years old, and has served me well until now. It looks as if it is going to have to go back for repair.

I was just wondering whether anyone else has had similar experience and whether an Olympus repair is likely to be successful. Also the cost of such a repair. I would then weigh this against the alternatives for replacing this lens' function.

Any help or advice would be appreciated.

Graham_of_Rainham 21st June 2012 03:14 PM

Re: 70-300 autofocus problems.
 
I too made the mistake with the switch :o

I can only suggest giving it a good exercise, prior to sending off or asking for a repair quote.

Good luck

*chr

Stewart G 21st June 2012 05:24 PM

I find many circumstances where my 70-300 hunts intolerable, but usually it's because I'm feeding it poorly, i.e., subject motion, camera shake, low contrast subject, etc. Once I eliminate the weak link (me) the lens' focusing improves. Perhaps do some tests on a tripod before sending it in?

timmypreston 21st June 2012 08:56 PM

Re: 70-300 autofocus problems.
 
The 70-300 usually does this when wound out fully as it searches the macro range first for some reason.

It improves if you focus on the subject zoomed out then zoom in in a couple of stages auto focusing on the way.

Also try moving away from your subject a little.

Batman 22nd June 2012 09:51 AM

Re: 70-300 autofocus problems.
 
Thanks Graham, Stewart and Tim. All good advice, but I have been using this lens for 4 years and I have learned to expect some autofocus limitations, although whwn I first had it I thought it was pretty good. No, it has definitely deteriorated very recently, to the extent that it is virtually unusable.

I do need to get it repaired, or replace it. I hadn't wanted to make any more major investments in Olympus kit until I knew what was in the future for the 4/3 system, so it looks like repair is the way to go as long as it is reasonably priced and has a reasonable expectation of success. Thanks again.

cychwr 22nd June 2012 10:47 AM

Re: 70-300 autofocus problems.
 
Have you tried cleaning the contacts ? use a pencil rubber, This worked on mine when it started misbehaving.

Batman 22nd June 2012 11:01 AM

Re: 70-300 autofocus problems.
 
Thank you. Yes I have tried various cleaning methods including a pencil rubber. I think the problem is within the lens.

Ross the fiddler 22nd June 2012 11:55 AM

Re: 70-300 autofocus problems.
 
I hope you haven't damaged the gears with the removal of the lens hood. Some people have not been careful enough in that respect & found out the hard way.

Stewart G 22nd June 2012 01:26 PM

I have read a forum post somewhere, of a 70-300 being sent in, out of warranty, and repaired for free, due to messed up gears. I've sort of come to expect that one day mine will need to go in, too. Its almost impossible to avoid forcing the gears in some way during use, as I'm sure you well know.

Ross the fiddler 22nd June 2012 01:46 PM

Re: 70-300 autofocus problems.
 
Quote:

Originally Posted by Stewart G (Post 172982)
I have read a forum post somewhere, of a 70-300 being sent in, out of warranty, and repaired for free, due to messed up gears. I've sort of come to expect that one day mine will need to go in, too. Its almost impossible to avoid forcing the gears in some way during use, as I'm sure you well know.

Yes, but unfortunately, to avoid damaging the gears, rotating the lens has to be avoided as much as possible, especially when removing the lens hood (by pressing against the lens cap or holding the extended barrel).

Olybirder 22nd June 2012 02:10 PM

Re: 70-300 autofocus problems.
 
I haven't used my 70-300 for over a year, since I bought the 50-200, but I found that it was easy to remove the lens hood from extended position by grasping the barrel to stop it turning. Removing it from the stored position is a much more tricky operation as the hood covers the barrel. I never clicked my hood in place when stored as I always kept the camera and lens in a bag, so the hood wouldn't be lost if it fell off.

Regarding the OP's problem with the 70-300, if it is hunting for 2-3 seconds before confirming focus, that is not too different from my 50-200 and EC-14 for much of the time. In fact it frequently refuses to focus at all if I am trying to photograph a bird in flight. I have just about given up trying to do so now.

Ron

Batman 22nd June 2012 02:20 PM

Re: 70-300 autofocus problems.
 
Thanks everyone. Although I've always tried to be careful when removing the lens hood, I suspect damage from this action may still be the problem. Interestingly, I don't think Olympus give any special instructions to prevent damage when doing it. If they do I haven't seen it.

I'm interested in Stewart's point that someone had their lens repaired for free. It would be good to confirm that.

Stewart G 22nd June 2012 02:23 PM

One of my favorite goofs is getting a finger caught between reversed lens hood and the zoom ring when the lens auto-retracts.

Ross the fiddler 23rd June 2012 01:19 AM

Re: 70-300 autofocus problems.
 
Quote:

Originally Posted by Stewart G (Post 172997)
One of my favorite goofs is getting a finger caught between reversed lens hood and the zoom ring when the lens auto-retracts.

:eek: I haven't tried that one yet. *laugh

Barkly 23rd June 2012 08:17 AM

Re: 70-300 autofocus problems.
 
Funny you should raise this today - I was in my home office doing a lot of filing and only filed my letter to Olly Oz this afternoon.

That was me that 'stuffed' the gears by mishandling and did it twice. Once under warranty and once out of warranty. Olly in Oz fixed it both times for free. I have now learned how to remove the lens hood without working the gears - i.e. push onto the lens cover while removing the hood.

Had the 70-300mm out todya - see my roo pic elsewhere. I sometimes find that it will hunt for focus when it can't get a clear image of the target. What I do is to drop back to 100mm - AF - then zoom in to 300mm and AF again. Alwys eliminates the hunting.


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