AF Lens Keeps Searching For Focus
Jun 21, 2015 23:04:21 #
My camera/lens combo is a Canon Rebel XSi with Canon Zoom EF-S 17-85mm IS USM lens. This has been my "walk around/travel" combo for several years. 'Till now it has performed very well. For the past few weeks however the lens, when in auto-focus mode, has had difficulty locking into focus. It continues to search for focus. I can focus it manually.
I recently acquired a Canon EF 50mm 1.8II. This lens focuses smoothly and quickly in AF mode on the same camera body, with the same settings.
Any ideas as to what the problem is with the Zoom 17-85 lens and how to fix?
I recently acquired a Canon EF 50mm 1.8II. This lens focuses smoothly and quickly in AF mode on the same camera body, with the same settings.
Any ideas as to what the problem is with the Zoom 17-85 lens and how to fix?
Jun 21, 2015 23:07:11 #
tovie wrote:
My camera/lens combo is a Canon Rebel XSi with Can... (show quote)
Did you try to make a step back?
Jun 21, 2015 23:46:44 #
tovie wrote:
My camera/lens combo is a Canon Rebel XSi with Can... (show quote)
Dirty lens
Dirty contact points
Auto Focus is about worn out
clean lens and contact points well, try again, contact Canon repair.
Jun 22, 2015 08:55:30 #
Could it possibly be that your newer lens with a f/1.8 aperture has exposed the 17-85 f/4 shortcomings when compared under the same lighting conditions? That is a two stop difference!
You are most likely aware, but there is also a Custom Function setting within the camera menu that deals specifically wth this auto focus searching issue. Have changed this setting recently?
Let us know if you figure it out. Good luck!
You are most likely aware, but there is also a Custom Function setting within the camera menu that deals specifically wth this auto focus searching issue. Have changed this setting recently?
Let us know if you figure it out. Good luck!
Jun 22, 2015 09:11:15 #
rjriggins11
Loc: Colorado Springs, CO
This problem is usually caused by a faulty focus lock sensor inside the lens. This is repairable .
Hi. My name is Rick. Im the owner and lead technician at Discount Camera Repair and a member in good standing here at the UHH. Ive been doing repairs for other members here at greatly discounted rates and would be glad to help.
I'd be more than happy to repair the lens for you and keep the cost as low as possible. If youre interested, please respond by private message or simply reply to this post.
Hi. My name is Rick. Im the owner and lead technician at Discount Camera Repair and a member in good standing here at the UHH. Ive been doing repairs for other members here at greatly discounted rates and would be glad to help.
I'd be more than happy to repair the lens for you and keep the cost as low as possible. If youre interested, please respond by private message or simply reply to this post.
tovie wrote:
My camera/lens combo is a Canon Rebel XSi with Can... (show quote)
Jun 22, 2015 10:46:26 #
tovie wrote:
My camera/lens combo is a Canon Rebel XSi with Can... (show quote)
Canon lists their lenses according to the type AF each has. Your EF50mm f/1.8II is rated in Group A which means it will AF using ALL possible AF points and will be fast to do so. On the other hand-your EF-S lens isn't even categorized by any group, it is just slow. Since you know from the 50mm that your camera is functioning correctly you might suspect that your mirror has some dirt on it. Since the AF operates through the mirror, dirt on that mirror could be causing your problem. If possible, do a complete cleaning of the mirror. or take it to someone who can. Your problem could be a minor one, and hopefully you can be on your way in no time. GL
Jun 22, 2015 11:24:12 #
I had this happened with a Tamron 28-70mm. I sent it back and got my money back. Sometimes you get bad equipment. That's what return policies are for.
tovie wrote:
My camera/lens combo is a Canon Rebel XSi with Can... (show quote)
Jun 22, 2015 11:31:41 #
gemlenz wrote:
I had this happened with a Tamron 28-70mm. I sent it back and got my money back. Sometimes you get bad equipment. That's what return policies are for.
Pay attention, George. The OP said, "This has been my "walk around/travel" combo for several years." Too late to return.
Jun 22, 2015 11:53:20 #
Hi
The EF-S 17-85mm IS USM lens you have is renowned for this problem. My own one has been into the Canon-approved repair shop 3 times for a fix. It's a mechanical failing of the sensor inside the lens which is basically a little plastic strip - tiny part, major impact. You'll probably find that it happens especially at the extreme ends of the zoom range ? Anyway, I have just about given up on this lens as, after 3 repairs (and a lot of £££s), it just failed again after one use. Time for a change of lens - this baby has a global history over several years for this fault and it's clear Canon take no responsibility for bad engineering on this model. Cut your losses and change lenses.
The EF-S 17-85mm IS USM lens you have is renowned for this problem. My own one has been into the Canon-approved repair shop 3 times for a fix. It's a mechanical failing of the sensor inside the lens which is basically a little plastic strip - tiny part, major impact. You'll probably find that it happens especially at the extreme ends of the zoom range ? Anyway, I have just about given up on this lens as, after 3 repairs (and a lot of £££s), it just failed again after one use. Time for a change of lens - this baby has a global history over several years for this fault and it's clear Canon take no responsibility for bad engineering on this model. Cut your losses and change lenses.
Jun 22, 2015 13:48:51 #
tovie wrote:
My camera/lens combo is a Canon Rebel XSi with Can... (show quote)
You might try using a single focus point. I like dead center.
I put the point over say my subject's eye, focus, then re-frame for the shot. This is of course supposing you're using multi focus points.
Jun 22, 2015 22:40:37 #
tovie wrote:
My camera/lens combo is a Canon Rebel XSi with Can... (show quote)
^^^^^^^^^^^^^^
Thanx to all for your comments and suggestions. I took the camera & lens to a camera store (a good one) with expert sales people. After testing the lens, they concluded that a control processor within the lens was the problem. They suggested a local camera repair shop but warned that labour runs about $100/hour. Since this lens, used but in good working order "ebays" for about $175 to $200 I doubt the economics of repairing the lens since I would have to settle for about half that amount. The lens does focus sharp in MF mode, with a blink by the focus point light and focus confirmation light in the viewfinder plus a ready "beep". It takes me back to my first viewfinder camera in pre-AF days but it works. Also, for situations where AF would be advantageous, I can deploy my 50mm 1.8II.
So, again thanx for your comments; I'll make do until I upgrade the XSi to the latest wonder on B&H's shelves.
Jun 22, 2015 22:51:05 #
Be ambitious, save your money and wait for the "Next Greatest Wonder".
Jun 23, 2015 11:15:23 #
rjriggins11
Loc: Colorado Springs, CO
The "Sales Expert" is wrong. The problem is a "Magnetic Resonance Sensor", or, MR Sensor for short. This is a common repair and if the expert actually knew anything, he would have known this right off the bat. I've replaced hundreds, if not thousands of them. That's how I make my living. God bless MR. Sensor.
Jun 23, 2015 12:10:49 #
tovie wrote:
^^^^^^^^^^^^^^ br Thanx to all for your comments a... (show quote)
Ask rjriggins, who has commented on your problem, about repair cost. He makes a living from repairing those lenses and other camera gear. Ask him what he would charge to repair your lens and if it is reasonable in comparison with a new lens, then have your lens fixed. No need to throw away a perfectly good lens only because you need to change a sensor in it. And buying a similar used lens on Ebay or Craigslist is a bit of a lottery, you never know how long it will last until you have to change the sensor in that one. Better to have a new sensor in your lens, then you know what you have.
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