Infinity adjustment?

[Frank Kolwicz]

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?

[Bob Atkins]

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".

[Frank Kolwicz]

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.

[Bob Atkins]

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

[Frank Kolwicz]

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!

[Frank Kolwicz]

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!

[Frank Kolwicz]

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?

[Bob Atkins]

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.

[Frank Kolwicz]

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.

[Bob Atkins]

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.

[Frank Kolwicz]

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.

[Johnny]

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

[Frank Kolwicz]

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

[Bob Atkins]

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.

[Frank Kolwicz]

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.