EF 24-70mm f/2.8L II USM Issues

[adfrick]

I have owned this lens for approximately 3 years and I have never liked it.  From the day I got it I've had focus issues with the lens.  My colleagues use this as their work horse lens, but I can't trust it.  I've just figured it was user error, but now I really need this lens to work especially with how much I paid for it.   I've read in other forums that the plastic rings can wear down on this lens, but I've had these issues since the beginning.

Can you ever get a bad lens out of the box?

Thanks,

adfrick

[ebiggs1]

"Can you ever get a bad lens out of the box?"

Yes you can but highly unlikely from Canon. Especially on this model. I don't have the series II version but I do have the first version. It is a 2005 model and has preformed extremely well. Yours should be even better.

This lens and the 70-200mm f2.8 are my favorite lenses of all time and I have been in this business for more than 40 years.

I will go so far as to say they are the best lenses of their type ever! Period, where did I hear that? 

If you think it has an issue, send it in to CPS and get it evaluated.

[adfrick]

Thanks for the reply.  I will send it back.

[TCampbell]

Which camera body do you have?

Plenty of lenses might be fine out of the box... but not fine for YOUR individual camera body.

Some bodies are able to perform lens auto-focus microadjustment.  (typically mid-level and higher bodies).  It may be that your lens needs to be calibrated (adjusted) for your body.

If you do send the lens in for service, it's actually recommended you send both the lens AND body so that Canon can evaluate and make sure that your specific lens is calibrated for your specific body.  (Basically two lenses and/or two bodies rolling off the assembly line are intended to be identical, but the truth is no two are truly identical.)

You might want to read the article "This Lens is Soft and other Myths" by Roger Cicala of LensRentals.  In the article (since he is a lens rental business), he talks about lenses that are perfectly fine... and yet some renters complain that the lens is not a good lens -- and he explains why this happens (and more importantly... what you can do about it.)

Here's a link to it:  http://www.lensrentals.com/blog/2008/12/this-lens-is-soft-and-other-myths

You can test your lens by using a focus target.  I strongly recommend against just taking typical photos with it -- so many things can affect the outcome of a typical photo that there's just no way to pin down the issue to being a "lens" problem.

You can buy or make a focus target. 

The target provides a high contrast center so that the camera sould easily lock focus on it... but the target is placed at a 45 degree angle (a slant) leaning back from your camera.  That way part of the target is nearer and part of it is farther.  It provides fine index marks all the way front to back.  This way, you can lock focus at the center, but check the results and notice if, for example, the marks one inch closer are actually sharper than the marks you focused on (indicating a focus error.)

It's important that the target and camera be stationary (use a tripod) otherwise the tiny sway of your own body after the camera locks focus will throw off your results.

I suggest manually turning the focus all the way in and forcing the camera to focus out on the chart at least a half dozen times.  (each time you focus and shoot, manually turn the focus ring back in).  Then repeat... only this time turn the focus all the way out (to infinity) and take a half dozen shots.  If there is some "slop" or gear backlash in the focus motor, then this will hopefully help you detect it (e.g. you would notice the focus accuracy in one direction is different then the focus accuracy in the opposite direction.  Of course what you want is a lens that is accurate regardless of which way it needs to adjust focus.)

Jeffrey Friedl's Blog has a good focus chart you can download and print -- "Jeffrey's Autofocus Test Chart"

http://regex.info/blog/photo-tech/focus-chart

You can also buy commercially produced focus charts.  DataColor makes a product called the SpyderLensCal.  Michael Tapes Design makes a product called the LensAlign.  These all follow the sample prinicple of shooting a target resting on a slanted angle.

[adfrick]

Tim,

Thanks a ton.  I will do this before I ship it off.  I currently shoot with a 5D Mark II, but looking to add the Mark III over Christmas if Santa hooks me up!

Drew

[TCampbell]

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@adfrick wrote:

Tim,

Thanks a ton.  I will do this before I ship it off.  I currently shoot with a 5D Mark II, but looking to add the Mark III over Christmas if Santa hooks me up!

Drew

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Both the 5D II and III support the lens AF adjustment. 

On your 5D II, attach the lens you want to adjust (e.g. your EF 24-70mm f/2.8L)

Menu -> Orange camera tab (on the right) -> C.Fn III:Autofocus/Drive

Wheel over to option #8 labeled AF Microadjustment.  You probably want to pick option 2:Adjust by lens

Press the "Info" button on the left of the display -- this will let you register the settings for the currently attached lens.

On the following screen it will display the name of the currently attached lens that it plans to register, and you can roll the focus some number of units forward or backward.  

You would do this after performing an initial test against the focus targets to determine if the lens is repeated either front-focusing or back-focusing, correct, then re-test the lens.  Do this until you are happy that it's arriving at correct focus for you.

I seem to recall the camera body can remember up to 50 unique lenses.

And if Santa does bring a new camera for Christmas, remember that any lens adjustment is unique to the lens/body combination.  In other words, your entire sensor could  be shimmed forward a few focus units on one camera (causing all lenses to be fractionally off) and then each unique lens may have it's own focus nuance.  A lens that happens to focus 3 units back (on a camera that happens to be shimmed 3 units forard) would cancel out and seem to be a 'perfect' lens (even though both are off -- they compliment each other.)  Move that same lens to a different body which is shimmed in perfectly and suddenly you'd think the camera was to blame (when really the lens is to blame.)  

ALSO... VERY important.  Since this is a zoom lens, they can be a bit more tricky.  It's possible that the focus accuracy at the 24mm end may be different than the focus accuracy at the 70mm end.  You may need to test at a few positions to find the settings that work best for you.

Lastly -- be careful to judge the focus in the center.  It is "normal" for optics to have softer focus at the corners and edges than it has in the middle.  While it's easiest to notice a front-focusing or back-focusing lens at it's widest aperture, that's seldom the best performance a lens can offer.  Most lenses yield their best performance when stopped down a bit.  I also own the EF 24-70mm f/2.8L USM (original) but I find that when the situation lends itself to letting me use any f-stop I want... I tend to use f/4 the most often.

[adfrick]

Thanks Tim, quite the education you're giving me.  I will try this out.

[amfoto1]

The tendency to wear "the plastic rings" (actually some nylon parte) that you have read about refer to the first version of this lens, not the newer Mark II you say you have. Some reviewers of the newer lens feel the problem - which typically only occurs with extensive, long term use of the lens (mine is 8 or 10 years old & no problems) -  has been corrected.

HOWEVER, if you have had the lens for 3 years, it's impossible that you have the Mark II version you indicate. That version was first introduced just over a year ago. So you must have the "Mark I" version.

Not everyone has CPS (Canon Professional Services) membership, which requires ownership of certain level and amount of equipment at a minimum. If you do, great.... contact them about having the lens checked out and repaired if needed. If you don't have a CPS membership... contact the Canon Service Department nearest you (check their website for info about that) and request the check and repair.

***********
Alan Myers

San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7D(x2), 50D(x3), some other cameras, various lenses & accessories
FLICKR & PRINTROOM 

[ebiggs1]

"I have owned this lens for approximately 3 years and I have never liked it."

I completely failed to comprehend this statement but Alan is correct, you could not have had a Series II for 3 years. Even two yrears, you would have had to get one of the very first ones, or one straight from Japan.

It is easy to tell the difference, however, as the series II has a "II" on the front element right after it's name. Plus the element is 82mm not 77mm like mine.

[adfrick]

It was my error on the post as it is the I and not the II.  I've disliked it since I've had it, but my colleagues love theirs!