Since you have to explicitly go into the custom function to make the adjustment, the casual shooters won't even mess with it. It'll be like most of the other custom functions. The person who is not really serious about it all won't even realize the feature exists.
So the folks who initially buy a DSLR just to have a fancy-looking P&S will most likely use the camera set to its defaults, in the "basic zone". And that's fine, especially as they start out. Later, if they learn more, and become interested in the potential of using more of the adjustments and customization, hopefully they'll have learned enough to put the features to good use.
People who do venture into playing with this feature always have the "return to defaults" to get things set back to normal in case they find that they've messed things up. I'm sure the people at Canon's tech support line spend a lot of time telling people to reset all custom functions to their defaults as the starting point for most troubleshooting. They probably hear a lot of the sound of people slapping themselves on the forehead after trying that ;-)
There are so many custom functions that a person can get set "wrong" already that I don't think there's too much danger of increased traffic to Canon repair due to this. After all, think about how easy it is to just get the FEC or EC set and then feel that your camera is horribly mis-exposing. At a certain level, in order to have the features we love on these DSLRs, you do have to give the owner a bit of "rope" with which to hang themselves. These cameras are already loaded with features and adjustments that could easily cause confusion to a new DSLR shooter.
The way I see it, the people who would be likely to play with the AF micro adjust are the people who would be most likely to return a camera to the dealer or send it in to be adjusted due to dissatisfaction with the focus. They're already on the verge of sending the camera in at that point. Perhaps if they felt that they had some control over things, and were somewhat responsible for the AF accuracy of their own camera, they might be more satisfied.
People like to feel that they've got some control over things and if they have that control, then they tend to take responsibility rather than blame the equipment or someone else for their problems. That's not to say that some of these cameras don't have problems, of course, and some of these problems could not be solved by micro adjust anyhow. But minor front or back focus issues, particularly with one lens and not another could be handled with this feature.
I see so many posts on this forum where someone is asking if they've got a problem or not. To me, if you can't tell that you've got a problem, then it must be fairly subtle. And that sort of subtle focus calibration issue is just exactly what the lens micro AF adjustment is meant to take care of.
Of course, inconsistent or grossly out of calibration problems should be returned to Canon for repair or adjustment. For one thing, Canon needs to have the feedback IMO. And for another, you shouldn't need to use something like micro adjustment to hide gross problems with the equipment. But I really think the intent of the micro adjust is simply to give us a way to handle minor adjustments.
Since the AF is specified only to achieve focus within + or - one DOF with all of the f/5.6 AF points, it could well be that this fairly wide tolerance, while within factory specs, is not good enough for people. If they've got a way to dial their exact camera and body combination in such that it's better than that, then they'll be happier.
For these small variations from lens to lens or just a slight body AF bias, this seems like a nice feature to have.
Still, I'm sure you're right that a few people would manage to confuse themselves with it. Hopefully, they'd just reset it to defaults before becoming too concerned, though.
I really do think that if people could map their own hot pixels and perform their own micro AF adjustments, it'd save Canon some money. Oly has given people the pixel mapping for years and I'm sure it saves them money along with making their customers happier.
There is a subtle psychological effect to this too. If you have an on-camera adjustment or auto-mapping feature, it says to the customer that these problems are not unusual and that they're expected to some extent. So people end up being more accepting of the appearance of hot-pixels. They just map them out. If this wasn't "normal" then the camera would not have a facility for taking care of it.
With a Canon, people are in a panic when they see a hot pixel. "Oh, no, my camera is broken. I need to send it back..."
The same is probably somewhat true for minor AF bias. If people had a way to tweak it themselves, they'd be less likely to view it as a defect or problem. It'd just be normal variation that we're expected to adjust on our own.
It's hard to say what Canon's thinking is when deciding not to provide this feature on the XXDs. It may be that they've weighed all of this and thought that only the "pros" could handle it. But I suspect that it's more likely that they just felt that they'd leave it off of the less expensive cameras as a way to add a feature to the more expensive ones.
Now that Nikon and others are giving it to the low-end bodies, Canon may feel more pressure to do the same. It's hard to say what they'll do or what their reasoning has been or will be. Sometimes it'd be fun to know exactly what sort of thinking does go on when these decisions are made.
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Jim H.
