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I've been told by a reliable repair shop that my 600/4L IS (not II) needs an "infinity adjustment" and that only Canon can do it. What does that mean?

I'd ask them. Never heard of it. There is no infinity stop on any of Canon's long lenses because changer in temperature can cause a slight focus shift due to expansion. Therefore they don't have a hard stop at "infinity" and so it isn't something that can be adjusted. All the lenses are designed to be able to focus "past infinity".

On older, shorter focal length lenses, Infinity focus was a hard stop and therefore the position could be adjusted.


Perhaps "infinity adjustment" isn't an adjustment for infinity focus but a name given to one of the parameters in the lens focusing algorithm? Canon can adjust the focus position of a lens (probably via firmware tweaking), but I've never heard it called an "infinity adjustment".

As usual, it's a waste of time and effort to try to get any technical info out of Canon. I called twice to the number given for the NJ repair center, using different numeric selections, and both were re-routed to the same-old Customer Service Dept. and a representative who knows nothing about tech, only about how to send stuff to them. I was told that tech staff will not answer phones and all choices on the NJ shop phone menu just goes to the Service desk.

The message is: send your stuff into our repair department black hole, pay $hundreds for shipping (2nd day for a heavy and expensive lens with some insurance) and we'll tell you that it meets spec when we send it back, maybe 4 to 6 weeks later.

If only Nikon were better! and I've been a Canon user since 1985.

What about your local "reliable repair shop"? Can they explain what they mean by "it needs an infinity adjustment"?

I just got an email back from the shop answering the question: since this lens has the mechanical ability to focus "beyond infinity" to allow for thermal effects, there has to be a soft/firmware adjustment that tells it to stop at infinity focus and not go further. This would explain why there are times when I can nothing in focus and those times are more likely to occur at longer focus distances - the lens puts the optical elements into an arrangement beyond infinity. Presumably, this affects manual focus as well, because there is no true manual focus on this lens, the mechanical focus input is translated into the electronics to move the elements.

I guess that also means that there is a separate element that adjusts for thermal effects and something causes it to stay there.

I hate guessing about this kind of stuff!

Well, I bit the bullet and sent the lens to Canon: after calling them 3 times I finally got passed to a technical representative who simply accepted my request for this specific fix. It may be hope against hope, but the infinity adjustment does sound like it may have been the problem all along and for my previous EF600/4IS as well.

Two data points don't make for any kind of statistical analysis, but 2 out of 2 used 600 purchases gave me the same kind of problems, so I'm wondering how common the need for this adjustment is and if the original 600 IS is prone to it. Canon's corporate super-secrecy sure doesn't help.

The thing that really pisses me off is that it has taken 2 years, shipping to 4 different Canon repair shops (and, including the previous lens, 5 trips to Canon repair), hundreds of dollars of shipping costs and the loss of thousands of images to get to this point. It's still not fixed, I only hope so!

Here we go again!

I received the lens back yesterday afternoon and spent 2 hours in the field testing it, then I repeated with two hours this morning after a microfocus adjustment that was obviously needed.

The lens is worse than when I sent it in. Of the several hundred frames I shot in AF and MF with focus bracketting, none of the frames are anywhere near as sharp as a recent one done with a 100-400L (hand-held) or the best images I got from the lens before it went in (and the 600 is supposed to be sharper than the 100-400).

It's the Canon run-around, apparently intended to force me to buy the latest model, rather than fix this one. In case you didn't follow my previous messages in this forum about my recent problems with the two 600/4s I've owned in the last 4 years, this has been the norm when there's a problem. It looks like I might as well try an after-market lens, what have I got to lose?

Must be frustrating. While every lens can't be the sharpest sample, with a lens like the 600/4L there should not be a very significant sample to sample variation, and if it's worse after adjustment than before something is wrong.

What I'd do would be to shoot a series of shots using a heavy tripod, mirror lockup etc. with AF and with manual focus bracketing, with and without AF microadjustment and send the results to Canon. It would be even better if I could borrow a second lens, so the same tests and show that those results were a lot better.

You could also try sending the lens to a different factory service center, There's on in NJ, one in CA and there's one in IL (though I'm not sure if they service "L" lenses there.

I really have not heard many (if any) other complaints that the 600/4L IS isn't sharp for a 600mm lens. It's not Canon's sharpest lens, in fact it can probably be beaten on the test bench by quite a few shorter primes like the 35/2 IS, the 40/2.8, the 100/2.8 macro, the 85/1.2, the 85/1.8 the 135/2, the 300/2.8 and maybe even the humble 50/1.8. However it should still be pretty sharp.

It's a pity there's no 3rd party test lab you could send it to for an impartial measurement of sharpness and focus accuracy.

I have no idea where to send images to Canon, there's no provision for doing so on their email contact form and their phone representatives have no technical skill to help with a problem of this kind or willingness to bump the question up the heirarchy or to get in touch with a tech specialist who might be able to help.

When I did this I was lucky enough to be within driving distance of the Jamesburg Factory Service center, so I went there myself and spoke with them in person. If you can escalate things up the chain of command it helps. I don't know where you are sending your lens, but take a look at the Canon website and see if you can find the name of a real person with some sort of authority and get in touch with them.

If you aren't a member of LinkedIn, join it then search on Canon. You'll be able to get real names of real people and perhaps one of them can help.

If You join Canon Professional Services maybe that's another way to go.

I don't know if you are expecting too much from the lens or not. Have you ever rented one and compared the two, or found someone else with the same lens and compared them? If you shoot at any of the usual wildlife "hotspots", I'll bet sooner or later someone else will show up with a 600/4 and would let you put your camera on their lens and take a few shots. It's very unfortunate that you have had two 600/4 lenses that have disappointed you. The odds would certainly be stacked against that happening, but it's certainly not impossible to pick two lenses that had problems.

Thanks for the details, Bob,

I did accidentally find a contact number via the web yesterday, just looking at various google listings for Canon, and have made a contact that is somewhere above the "Customer Service representative" that is so unhelpful with this. So I sent her two images, one of three made with my 600 (on my Gitzo/StudioBall in LiveView at 10x to see that there's no movement, 1/2000 second and a cable release) and one with my 100-400 and the difference in sharpness is striking; also, it's obvious that the plane of focus of the 600 is on the target, but extremely soft compared to the 100-400, so it's not a missed focus issue, it's just poor resolution.

I have rented lenses on three occasions and shot them side-by-side with mine and got the kind of results I expect with the rented lens, which is far superior to what my lens produces. I have sent the two 600s I've owned to Canon 6 times now and at no time did either one come back improved (that's why I traded the other one in, informing the buyer of the situation). I have also sent my current lens to 3 different Canon authorized repair shops to no avail. As of right now the lens is a paper weight.

One thing I've gathered from all this expensive loss of use of the lens: Canon does not check the actual performance before it's returned to me - it seems that they just muck about with the mechanicals and, if they don't find anything, pack it up and send it back. The alternative, that they do check the performance and see what I see, is even more disappointing, because that would mean that they don't care that I have a non-functional ($multi-thousand$) professional-grade, top-of-the-line, lens and would prefer that I just go out and buy the latest version.

The first lens didn't come with problems, it worked fine, but was broken when a gust of wind slammed my car door against my back and sent the lens onto the gravel - it's just that Canon never repaired to it's previous optical performance with 5 trips to their CA and NJ service centers and I'm afraid that this one is going to be treated the same.

I've attached a cropped JPEG of the original .CR2 image file I sent to Canon. Check it at 100% and look at the texture of the driveway to see the plane of focus and how soft the image is on the target. Remember - there is no discernible movement of the image in LiveView at 10x during exposure of 1/2000 sec., so it's not camera movement. If you want to see how sharp it should be, I can send a file of the same test setup from my 100-400.

The test image is very soft, Frank. Hope they will fix the lens for you.

Thanks, Johnny, I'll be entering the Canon repair merry-go-round again as soon as I get a return label.

I'd agree that those images look a bit soft. I'd expect better from a 600/4L.

If the lens has been dropped or suffered in transit, it's possible an element got tilted or displaced. Shouldn't happen with a lens built to "L" construction standards, but it's possible. They'd never find that by focus adjustment. They'd have to actually do optical tests, and/or strip the lens down. I'm certain that Canon must have optical testing capability at their major service centers.

It isn't over, yet, but I got a call from a Canon repair representative yesterday requesting my camera and the 1.4x because they can't find anything wrong with the lens, so I guess they're punting again by claiming the softness is due to camera movement.

If camera movement during exposure with the camera on a tripod, in LiveView at 10x to be sure all motion has stopped, 1/2000th second and a cable release yields soft images, what does it take to get them sharp? I have asked for their test images that show that the lens can reliably produce sharp images, but was refused.

It's time to consider other options, other than Canon, that is.

Doesn't sound like there should be any camera movement under those conditions unless you have the lens mounted on a bowl of jello!

What's your alternative? Switch to Nikon? That's going to be expensive and I've heard complaints about Nikon lenses and service too.

I'd give Canon what they want (camera and 1.4x) and ask them to send you their test images before they return the lens if they say that everything is as it should be.

I did exactly what you said, the camera and 1.4x were shipped the same day I talked to Canon.

The representative's reply to my request for their test images was flat refusal - "we don't do that". She also claimed that the tech detected "slight motion blurring". No mention was made of the comparison shots made hand-held with a 100-400, at 400mm, that I included, which show what a minimally acceptable level of sharpness should be.

The tripod setup was at the back of my concrete garage floor: not only maximally stable, but sheltered from any possible wind. If that lens can't produce a critically sharp image under those conditions, when could it?

It occurs to me that maybe this lens was damaged (I bought it used), as Bob suggested, and that they aren't repairable, if the damage is bad enough, or at least not repairable at a price Canon is willing to charge (out of warranty) and have it known just how fragile they really are. Corporate sandbagging of equipment faults, does that sound familiar?

If it was me I'd bug them on the test images. Why won't they provide them? Don't they take any? They can't be proprietary. If I had a lens I was really unhappy with I'd demand to see some image that they shot that they considered acceptable. If the tech rep said "we don't do that", my reply would be "then can you connect me with your supervisor". Not sure what I'd do if they said "we can't do that". I'd try to get the name of their supervisor at least. Last resort would be to ask for an address or email address where you could send complaints/questions.

I can't see any reason why they can't supply test shots. It may not be their policy or standard practice to do that, but that doesn't mean they can't. They must be taking test shots if they wanted the camera. You can certainly test a lens on its own without a camera using and optical bench and the right targets and optics, but I don't see how you can check it's working with the camera without actually taking shots with the camera.

I don't know what you sent them in the way of test shots. To detect camera motion you'd really want something like an image of a Siemens star in the center of the field and look for decreased resolution in the direction perpendicular to the motion. You're basically looking for different levels of sharpness in different directions in the center of the field (where astigmatism is zero). It would be pretty damn hard to get camera motion with the lens on a decent tripod, mirror locked up, remote release, 1/2000s shutter speed etc.

I'm not saying that they are wrong, maybe something is going on I don't know about, but if they came to conclusions about the image that differed from mine, I'd at least want a technical explanation of what they were basing their conclusions on.

I can see their side too. I'm sure they get complaints about cameras/lenses from users who don't know how to use them or what to expect from them, so they may tend to be a little wary of such complaints, even when they are justified. I very much doubt that there's any corporate conspiracy to hide defects and problems.

Lenses like the 600/4L are made to take hard professional use. I doubt there's anything that would make such a lens "beyond repair to original quality" unless a tank drove over it.

It's a pity there's no independent 3rd party professional testing lab you could send a lens to and get back an optical quality report. Of course such a lab would likely be pretty expensive, plus you'd still have to get Canon/Nikon or whoever to accept their test results and there's always a question of what does and doesn't fall within the normal lens to lens variation and what the lens should be. If you tested 100 lenses of the same type, one of them would be best and they can't all be that good, but the variation should be small. One of them will also be worst of course...

The images I sent them were the .cr2 versions of the one I posted here - a B&W checkered card on a neighbor's driveway about 150 feet away, across from my garage, and the same setup done with the 100-400L on the same camera hand-held at about the same magnification, so at about 1/2 the distance. 3 of each with the focus shifted and re-focused between shots. Those images clearly show a lens that cannot achieve a decent level of sharpness and I agree that seeing "slight softness due to camera movement" in those images would be impossible, swamped as they are by bad focus.

As far as I have ever heard, and I've been a Canon user for more than 25 years, Canon never gives out any information about problems until they can't dodge them anymore and this silent repair policy is in line with that total secrecy about what they are doing or have done with OUR equipment. Canon authorized repair shops are also forbidden to give out much information under non-disclosure agreements in order to become authorized. That's full-fledged corporate, cover your ass, secrecy, whether you believe in it or not.

Nikon does the same thing, so wipe that smug look off your faces, fanboys!

I think Canon don't acknowledge problems until they are pretty sure it's a design or manufacturing problem when it comes to a defect in a lens that warrants a recall and free fix, but they do do that. There was the rear aperture stop in the 24-105 that was replaced due to flare issues I think. There was also a fix for the 75-300 IS to do with differences when the camera was held horizontally and vertically. I'm sure I remember other examples, but those were the two on lenses I owned.

I don't think there is a general design issue with the 600/4L IS. There are thousands of them out there and very, very few complaints.

I've found Canon to be quite good at acknowledging that a particular lens has problems. That actually sent a 300/2.8L I owned back to Japan for repair and testing and replaced a bunch of the optics. Then again though, I was able to actually talk with the tech staff at Jamesburg by visiting them.

I hope you can resolve your problem. If you can get them to give you a better explanation and to send you test images, it would go a long way to resolving the issue. I really don't know why they seem reluctant to do that.

UPDATE:

I heard from Canon this PM and was told that the tech and the service person were going to do some field tests with my camera/1.4x/600L (I hope they have fun) following the regular bench tests. I also hope this lets my lens get fixed this time.

High hopes here.

It's been two days since the Canon repair people said they were going to do some field tests with my 600, 70d and 1.4x and there's been no response. I presume that, if they had gotten decent images, I would have heard immediately, so hopes are rising from this battered and dejected soul who has been without a fully functional right arm since I broke the first used 600mm lens.

Update: remember the masks that adorn old-fashioned theaters - comedy and tragedy? That's where I'm at.

I got the lens back yesterday (the camera and 1.4x are in another box taking a different route) and, after a delay of two weeks when the lens went somewhere (otherwise why did it take so long?) and then back to Irvine for return to me I'm happy to say that it now actually focusses, sharply.

On the other hand, now the lens no longer has IS and AF can't be shut off! It makes one wonder, or it makes ME wonder, how the hell that got through final inspection?

I do have to thank the Canon service reps who handled the case this time and listened to me on the phone and didn't just put it through as another regular item to be processed. The woman who took my call listened, without interruption, to my entire rant on how this lens and my previous 600/4 were routinely passed though their repair service (6 times) without the least improvement in focus, but maybe I finally got somewhere only because it came back significantly worse than when it went in and couldn't focus at any distance or frequency. Maybe the lack of critical focus just wasn't enough for them to do anything or, maybe, the US repair service can't handle something that involves realigning the optical system, not even the main center in New Jersey and that might explain the more than a week of silence and delay after the Irvine center was supposed to have run extra tests with my camera and extender and my sample photos to show how bad it was.

This lens has been out of my hands since May 5th - on it's way to Canon repair and back and out again and now back again to be shipped out again next week. I can only hope that fixing the AF and IS doesn't screw-up the optics when I get my hands on it in the future.

What a mess!!!  ??? Don`t give up!  :)

Thanks, Johnny, but at some point you have to make choices.

I've got the lens back and there is some improvement, especially versus the poor optical performance I got after the last "fix", but the lens is nowhere near as good as an old, beaten-up one I rented last year - that lens produced beautifully sharp images 9 times out of 10, mine only produces barely acceptable images 1 time in 10. Analysis of the image files shows that focus is bouncing all around the subject, even a high-contrast black and white grid target in full sun, which should be the easiest thing for AF to grab onto.

Using LiveView, things are better, but that's no help with moving subjects as the focus is too slow and sometimes hunts the full range of focus before settling down and that takes a couple of seconds while the subject walks out of the frame and has to be found again and focus hunts again, etc.

It's a total waste of time to send it back again, Canon is uninterested in or unable to bring this lens back to how it performed when new and I think this may be the general case for the supertelephotos: break them and good luck to you in restoring optical performance. Mechanically, yes that works, but optically. . .

The way things stand now, I can't rely on getting any kind of critical focus with one or two frames; if I can't shoot at least a couple of dozen, there is little likelihood of finding a usably sharp image. Now I have to try to find uses for unsharp images, as that is what I have, mostly with this lens or hope to use my 100-400 instead, which can be relied on to get good focus almost every time without LiveView.

Much ado since the last message.

While dicking around on the web looking for info on telephoto technique (I am a pessimist and always think this problem is my fault, first) I accidentally found a scientist who knows a thing or two about optical performance (I'm withholding his name, as he may not want to be deluged with other such problems) and he had me do some specific kinds of test images. On review of the image files he said that the lens has specific kinds of aberrations due to either a misaligned optical element or "wedging".

I joined Canon Professional Service and then sent those files, some field test shots and a new batch of images of my cross-hatch test target along with target files from a rental 500/4LIS(II) for comparison with the lens, 1.4x and camera body back to Irvine. The difference in performance between my 600 and the rental 500 was very obvious! Needless to say, but I'm saying it anyway, the comparisons were done under identical conditions.

It finally has come back fixed. It is not quite as sharp as the 500/4, but produces much more usable images than before and handling it is giving me that pain in my shoulder again - I have come to enjoy that pain instead of the stomach cramps the repair service has given me.

To all apologists for Canon service I have to ask: why did it take all of this effort to get what should have been routine in dealing with a lens repair - optical performance? Do ordinary users who don't qualify for CPS (or think to join it) always get short-shrifted on service - doesn't our money entitle us to the same quality service a CPS member gets for the same financial outlay?

Of course I'm pissed! It has cost me 2 years of lost productivity and photo opportunities, thousands of dollars in shipping costs and thousands of dollars in lost equipment costs since I broke that first 600/4LIS(I), gave up on getting it repaired and had to do it all over again with another used 600/4 with the same kind of problem.