Canon EF 70-300mm f/4-5.6 IS USM has gotten blurry at full zoom

[davewo]

Does this sound familiar to anyone? I have had the 60D and 70-300 lens for about a year now. I use the camera primarily for birding. It used to take very sharp pictures at full zoom even after cropping as long as I was fairly close. Recently I have gone out birding several times, but  none of the pictures were sharp. I put this down as operator error for a while until I realised I had not gotten a good shot in quite some time. I did some experimenting using a tripod taking pictures of a birdfeeder right outside a window. At 70mm the images are sharp weven after heavy cropping. At full zoom the pictures are never sharp. I tried turning off IS and using manual focus, but still it appears there is something wrong with the lens. I also have a 50mm 1.4f that takes great pictures so I think that rules out the body. Can a lens be tuned or adjusted? Right now its useless to me.

[cicopo]

Sounds like internal problems & yes it can be given a "tune up" or be re calibrated but it may also have worn or damaged parts. Either way it needs a trip to a repair shop or Canon.

Edited to add.

By any chance have you recently added a filter to it or do you have a filter on it. If so test without it on the lens to see if that's the problem.

[davewo]

I have not added a filter. In fact, during troubleshhoting I removed the UV filter I have been using for the last year, but there was no difference. Do you know would there be a difference in sending this back to Canon or can a local shop do this kind of work?

[ebiggs1]

Which Canon EF 70-300mm f/4-5.6 IS USM is it? Is it the white one?

If not, it may not be worth having it fixed as a new one will be nearly the same cost.

If it is not the white one already, this is a good excuse to check one out. They are great lenses.

[davewo]

This lens costs $600.00. http://www.amazon.com/gp/product/B0007Y794O/ref=oh_details_o06_s00_i00?ie=UTF8&psc=1 

Does it cost that much to repair? Thats not good. I guess I need to try to find a local shop and see what they say.

[ebiggs1]

No it shouldn't cost $600 but depending on what the problem is, it could be several hundred bucks. I have seen that lens for as low as $330 up to $650, so it would depend on where you get it. Best Buy and some others are selling it for $548 right now.

You must decide if a few hundred, if that is the case, is better for a repaired lens or a few hundred more for a brand new one?

And of course the "great white" Canon EF 70-300mm f/4-5.6 L IS USM is around $1600 bucks. But if you can swing it, it is a fantastic lens. Built like a Sherman tank. It has all the qualities that make it an "L" series lens.

[cicopo]

It's hard to estimate a cost when none of us can know whether it just needs calibration or a full tear down & some parts.

[davewo]

I have no problem with the $1600 cost. It's the cost of the subsequent divorce that would soon follow that I have a problem with :). I guess I will just have to check out some one local to take a look.

[cicopo]

Another alternative seems to be the newest Tamron 70-300 VC

[ebiggs1]

"...  the subsequent divorce that would soon follow ..." 

I am aware of that feeling!

But after some 40 or 50 lenses and a few dozen cameras she gave in and I don't really know if she knows when a new one comes home or not.  

But since I retired I don't buy much anymore. For one thing I will never use all the stuff I have now.