My new lens is front focusing ... what would you do? Need advice please

[KrisztinaK]

So I bought a new lens about a week ago and have taken quite a few shots with it to test it out "in real life" shooting scenarios.
My keeper rate was pretty low though, with many missed focus shots.

So to 'unofficially' test the lens, I took some photos of my kids just watching TV one night.
They were both perfectly still and I used my external flash.

The lens appears to be perfect with subjects up close (<4' away) and front focusing with more distant subjects.

So I know the lens is bad, but here is my "what would you do" question ...

This is a brand new 24-105L lens, however it is a "white box" variety so I was able to purchase it significantly cheaper than a "standard" new lens. Also, it was purchased online, making swaps harder.
Brand new = $1130 White box = $ 860

I don't want to ship it back for exchanges until I get a good copy b/c this could really add up if I need to do a few swaps.

Would you ...
1) Just return it, chalk it up to a mistake of ordering online, and shell out for a new copy at full price?
2) Keep it and have it re-calibrated by Canon?
I'm only worried about this option since once I decide to go through with it I will definitely not be able to return it, and what if they cannot get it to an acceptable IQ?
OTOH, if I buy a new one from B&H or Adorama, a swap is just a short train ride away.

With these kinds of lens issues, does Canon have a pretty good track record of fixing the lenses?
I am feeling kind of lost since I've never (fortunately) had to deal with a bad copy of a lens before.

 

[gsgary]

What i would do is learn how to use it, i have had no problems with any L lenses i have ever bought when i first bought my 300f2.8L i wondered what the hell i had done but it just took a bit more time to get used to it

 

[KrisztinaK]

Thanks for taking the time to reply.

However, I know how to use this lens. I have been shooting with the same exact lens since 2007. This is second lens I bought, the same lens. I recently upgraded my camera body and gave the old body to my BF. With only one lens between the two of us and two bodies, I needed a second lens.

I have LOVED my first 24-105, which is why I bought another of the same...

 

[KrisztinaK]

My first 24-105, I had 80-90% keeper rate (with focus) chasing toddlers around.

This new copy, I am getting completely out of focus eyes on a perfectly still subject. The plane a few inches in front of him is in focus.
BTW, I always use single focus point, focus on thr near eye and do not recompose after locking focus.

 

[pgriz]

Can you get a good focus when the camera is on a tripod, and you are using live-view for focusing manually? Can you get your old lens back and test it in exactly the same way? If the two lenses give you essentially identical focusing with manual/live-view focusing, then the problem may be with the AF mechanism in the lens. If the two are NOT the same, then the lens itself may be the issue. Either way, you need a baseline for testing that eliminates as many possible factors as possible.

Edit: I have another member some ideas of how to set up a focusing test here (http://www.thephotoforum.com/forum/photography-beginners-forum/322738-help-focus.html#post2914780, entry #6). This would be the steps I'd take to figure out what is going on. In your case, I'd do the same with your old good lens and compare the two.

 

[KrisztinaK]

Thanks for the reply. I will take a look at your link when I get home from work.

I did want to add that I did do a comparison of the two lenses in the first few days. I used dominos sey up at a 45 degree angle to the camera. The test was flawless but the tests were all run at close range.

I was planning on repeating the test from further away, probably with printed text. I would be very suprised if a problem is not confurmed.

 

[bratkinson]

Since you presumably still have access to your BF and your previous 24-105, swap lenses with him. If the problem recurs on his camera as well, it may, repeat, MAY, be a lens problem.

But before going through all the hassles of returning a lens, if your camera supports micro focus adjustment, then do it. While my 24-105 L worked 'very good' on my 60D, now that I've moved to a 5D3, I found it was a +5 in the MFA department. My shots are now drop-dead sharp and spot-on focused.

Plan B: send your lens and camera to Canon and they will make whatever adjustments are necessary.

Edit...I just noticed in your signature you have a 60D. No MFA capability. Try swapping with your BF.

 

[KrisztinaK]

I just wanted to pop in with a quick update ... and to thank everyone who has posted in an attempt to help me diagnose my problem.

I took the time this past weekend to set up a focus test to check out my problems. I took a sampling of both lenses paired with both bodies.
I was not surprised to find that the new lens does have some sort of issues with focus. I have never had such a low keeper rate as I did in the first few weeks of using it.
I've had this same lens for over 6 years and am pretty familiar with it, so I just knew something was wrong very early on ...

I never did get a chance to test with manual focus. The only time I was able to do this was at night with really bad indoor light. I used my flash the whole time, so Live View was impossible.
But I tested the AF extensively and was not happy with my results. I will post some of my shots if there is interest in seeing them.

Ironically, my old lens has a back focus problem for some time now. I am 100% positive on this and have tested several times for it, which is why I opted to replace it in the first place. I decided I'd rather spend a bit more and just replace it instead of fixing it and this is the ordeal I've been dealing with since that decision.
The last test I just did gave me consistently back focused images on the older lens. I was going to have it fixed at some point anyway and either keep it for my BF to use in the future or sell it. He is not in a rush to learn, believe me, so I may even opt to sell it once it has been re-calibrated. I'm not really sure what I'll do with it, I will decide in the next few weeks.

I am actually dropping off all three of them at Canon NJ tomorrow. I will have the 60D and the new lens calibrated together and hopefully that will be the end of my problems.
While I'm there, the old lens will get an estimate for a calibration. At that point, BF can decide if he wants to tkae it off of me or I'll just take it down to B&H to sell it and offset the cost of the replacement.

Sounds way more complicated than it really is, I know.

Thanks to all for taking the time to help me.