Four Canon Items - Five Focus Problems

Bob Blount said:

Some have suggested the I (Canon's suggestions/findings) don't know
what I am talking about. Canon's work orders state the problems
going in and what the corrective action was so maybe Canon service
needs to be straightened out by some of the experts on the forum.
The results speak for themselves.

Click to expand...

If you keep coming to this forum ( or any other forum) you should have noticed that a certain part of the poster have the following logic: "you could not get a flat tire on that road because I drove there and my tires are OK. So the problem is that you cannot read the tire pressure gauge".

Fortunately there are not too many of them. Unfortunately they poke their noses into anybody's post who is asking for help with focusing and splashing saliva start screaming about poster's credibility.
So I would not pay much attention to what "some have suggested ".

As for your peculiar problem I suspect that the camera knows which lens is mounted on and focuses differently. So it easily can happen that it misses one lens while focusing correcly all others. This is only my guess though.

Don't be shy. You can name me by name if you're replying to my post.

Chuck Westfall has repeatedly confirmed that Canon does not adjust lenses to specific customer bodies.

I accept his expertise.

I'm wondering if what has actually happened in cases where people believe that their lens or body was "matched" to their body or lens was:

Equipment was sent in repeatedly and still the customer was not satisfied. At that point, Canon recommends sending everything in together which the customer does. Canon then takes great care to be sure that everything is set correctly, perhaps using a more senior technician to do the work because they've obviously got a very unhappy customer on their hands who has gotten things back still not working.

So they take their time and do a really good job of setting both the body and the lenses. But still, they set them to standards. The result is that everything now works together very well, and they can confirm this before sending the equipment back to the customer.

Now the customer gets their equipment back, and bingo! It all works well. The customer then assumes that because they sent it all in together this time, Canon must have used their body with their lens to perform the adjustment.

This could easily not be the case, yet the results would seem, to the customer, to "prove" that this is what happened. Of course, this assumption is based on faulty logic, but still, it could seem that way.

I have also seen that the level of command of the English language shown in various correspondence from Canon tech service is often less than perfect. And they don't appear to take much time composing their work descriptions. So, again, what the customer ends up reading can be confusing, misleading, and ambiguous. So I think we have to be very careful interpreting what we're told over the phone and what we see on the repair tickets.

Do you have copies of documentation or correspondence with Canon which states that your body or lens was, in fact, adjusted out of normal specifications, in order to make these pieces work well together? If so, I'd like to see it and will gladly stand corrected.

I will also be extremely disappointed.

If Canon cannot achieve proper operation of a given body/lens combination without adjusting either the lens or the body to be anything but "dead-on" with respect to their standards, then either the body or the lens should be repaired or replaced. I hate the idea that there are bodies and lenses floating around out there which have been purposely "mis-adjusted" so that they'll work well with a particular mate.

--
Jim H.

Lin Evans said:

Hi Leon,

On some of the new Canon bodies there are firmware provisions which
allow precisely fine tuning the body to a particular lenses (the 1D
Mark III for example). Why this was necessary and if necessary on one
Canon body why not on all has always puzzled me.

Click to expand...

Yes, I have the 1d3. The adjustment range is not large and seems intended not to fix significant problems but to provide an improvement for lenses that are already within spec but still not spot on.

Member said:

Over the years I've had more problems with Canon and focus issues
than with all my other dSLR's combined. Perhaps I've just been
unlucky and fall out there on the third standard deviation, I really
don't know. One would "think" that when a lens works correctly with a
number of bodies and doesn't work correctly with another that the
probability would be the camera body - at least from a logical
probability perspective. But that "may" not always be the case. It's
quite an expensive proposition to ship a half dozen lenses and
multiple camera bodies back to Canon service to find out though with
with insurance, time without the use of the tools, etc.

Click to expand...

I had problems with my 10D and one lens (24-70) but have had no problems with two different 1d2's or a 1d3.

--
Leon
http://homepage.mac.com/leonwittwer/landscapes.htm

I agree that camera bodies and lenses coming out of production are spec'd to be within a range. I do think, however, that when they do calibration at a repair facility, they do try to get as close to "zero" as possible with respect to the standard lens or camera. In any event, some cameras already provide the user to do a more precise adjustment and I expect that most if not all will have this capability eventually.

S Clark said:

Canon calibrates to within a scale of acceptable specs. They do not
set your camera or lens to 0. It is considered acceptable if within
range of say -5 to +5 which means if you have a lens set to -5 and a
camera at +5 focus will be far from perfect.
--

Click to expand...

--
Leon
http://homepage.mac.com/leonwittwer/landscapes.htm

I remember to have read, that the specification is in terms of the DoF (1/2 of the DoF or something like that).

Now, if you have a camera which is within the specs, with +x, and a lens within the specs with -y, then the combination may suck. I guess when you send in both the camera and the lens, the technician checks if the combination is not so bad, and if it is, he adjusts them to a tighter tolerance.

Btw, the high-end cameras have a tighter "acceptability", IIRC it is 1/3 DoF.

--
Gabor

http://www.panopeeper.com/panorama/pano.htm

This time you are wrong Jim. I in no way meant you.

Having worked in the aerospace industry for 40 years it is not uncommon for tolerance buildups to produce unacceptable results. If the lens is at one end of its tolerance and the body is at the other end it may not produce acceptable images.

In order to rationally address this problem it is appropriate to have the lenses and body at the service center to correct the problem. If all items are adjusted to the center of their tolerance the problems may go away. I was not in the lab or privy to exactly what was done but am exceedingly happy with the results.
--
Bob

'There are always two people in every picture: the photographer and the viewer.' - Ansel Adams

Canon 40D, 70-200mm f4L IS, 28-135mm IS, Sigma 17-70mm f2.8 Macro, 100-400 mm f4.5L IS
Sony R1
Canon Pro1

GaborSch said:

I remember to have read, that the specification is in terms of the
DoF (1/2 of the DoF or something like that).

Click to expand...

So what does DoF mean ? I understand when one says 'shallow', 'shallower', 'deep' etc. But is it valid to put DoF into equasion?
Can you say Dof is 20 mm from a distance of 50 cm ? Where is the DoF edge ?

When they talk about the specifications for AF accuracy, Canon states that all of the AF "points" will provide AF accuracy to within one DOF. The center "high accuracy" AF point will provide AF accuracy to within 1/3 DOF, but the high accuracy sensors at the center "point" are only activated when a lens of better than f/2.8 is mounted.

This is so because those high accuracy sensors have a longer baseline, and thus require the larger aperture or they will "black out". This is the same reason why people get into trouble when they try to use lenses or lens/TC combos that result in apertures exceeding Canon's specified f/5.6 for AF operation. At smaller apertures than f/5.6, even the "standard accuracy" AF sensors "black out". This results in flaky AF operation.

Anyhow, back to the point:

DOF, in this context, is Depth Of Focus, and is described by Doug Kerr in this article:

http://doug.kerr.home.att.net/pumpkin/AF_accuracy.pdf

--
Jim H.

I have sent my two cameras in to Canon's Factory Service in New Jersey, and they got it all perfect the first try. Granted, I don't have a 100-400mm lens, but they got my 4 lenses calibrated very nicely. It sounds like some others have had issues with the California service facility.

Other than some extra shipping expense and transit time, why not send it to the New Jersey facility instead? It would be better if the two did equally excellent work, but the California one sounds like they deal with a lot more volume than the New Jersey one.

...and Canon won't fix it under warrenty...damn Canon !



--
Robert
http://www.pbase.com/rgravel/mes_photos

Rowbear said:

...and Canon won't fix it under warrenty...damn Canon !



--
Robert
http://www.pbase.com/rgravel/mes_photos

Click to expand...

Robert,

Quebec has very sophisticated consumer protection laws, so maybe you could discuss it with them.

A friend of mine in Montreal had trouble with an HP point and shoot. HP told him he was SOL, but a call from the Quebec Consumer Protection people soon changed their mind.

I am assuming you purchased your 40D in Quebec, else you are still probably out of luck. Damn Canon!!!

Roy

I purchased it in Ottawa...still out of luck
--
Robert
http://www.pbase.com/rgravel/mes_photos

Rowbear said:

I purchased it in Ottawa...still out of luck

Click to expand...

Can't you send yourself back in for calibration?

;0)

OK guys, you are scarring me. I'm considering to buy my first dSLR set very soon and wanted it to be 40D, eventually ordered from B&H or other. But I surely would love not to have to resend camera or lenses back to the States or experience all I have read you did. Well, I know that you never know but.... I'm not a pro and this things make me wonder if this problems occure too often.

Are they? And....hope I understand well, you don't have to calibrate the lense with the body if there is no problem, right?

Apparently you have to be more explicite in order to avoid being misunderstood.

Like

This darn camera is not working without the battery

or

Autofocus is not working if I don't remove the lens cap

--
Gabor

http://www.panopeeper.com/panorama/pano.htm

Loki,

my 40D has been fantastic since I got it last September - absolutely faultless.

AF is excellent, IQ is wonderful, and just does everything reliably and well.

Keith, thank you!

You brought some light.. I was really starting to worry. Needed to hear something positive.

Then you might wish to read this, Loki:
http://forums.dpreview.com/forums/read.asp?forum=1019&message=27715305

And there are several threads like it.

The fact is, most "new camera" problems are user error - absolutely no question about that - and that by far the largest number of 40Ds are fine.

It's also true that people make the most noise when they're complaining (been there, done that, changed systems from Nikon to Canon...): satisfied owners - the vast majority - tend not to be so motivated to post about how good their camera is.

I guess that - to use a cliche - they're out there taking pictures...

--
Robert
http://www.pbase.com/rgravel/mes_photos