What's it been now, 15 years? That's how long I've been supporting Nikon users on the Web. And it just seems like I see the same complaint over and over. Got two more of them yesterday, one from Canada, one from Europe. My proposed solution for Nikon is still basically the same, but maybe I can make it more modern and trendy so that Nikon will be more likely to copy it.
Nikon needs a Genius Bar at their repair facilities. Not the Dummy bar they have now. What's prompting me in writing this (this time)? Autofocus system adjustments.
The last two times I've surveyed Nikon DSLR users (now over 20,000 responses) I've gotten the same results: about 7% of all Nikon DSLRs end up back at Nikon because of "a focus problem." I don't think Nikon is any better or worse here than the other brands. Focus is one of the most common things to complain about, and way back in the early 90's Herbert Keppler at Modern Photography (at least I think it was still Modern Photography then--it's Popular Photography today) wrote a seminal column about "accuracy of SLR autofocus systems." In short, they weren't. Perfectly Accurate, that is.
The "why" behind that is full of technical issues, but two things have always been clearly part of the problem: alignment and tolerance. We can't do anything about the tolerance bit. It's built into the systems. Once a phase detect AF system thinks it's within some percentage of error of where it's supposed to be, it stops. The only alternative would be to constantly hunt, and we don't want that. So one problem is that a focus system will often stop at a slightly different point coming from infinity than it does coming from close focus. That difference may be really small in physical terms (a millimeter difference in focus distance, for example), but it is a difference that makes that can make problems for some photographers.
But that's coupled with manufacturing alignment tolerance. Remember, light is getting to most of these autofocus systems by going through a mirror (lots of light siphoned off), bouncing off another mirror, getting into the AF subsystem, and often bouncing off yet another mirror before being split by prism to get to the AF sensors themselves. Oh, and your lens mount could be slightly skewed, causing sensors on one side to get light that had traveled less or more than the other. Some cameras were notorious for issues (the D2 series) because they actually had three separate AF modules, and it's tough to align all three exactly the same.
A really well-trained Repair Genius at the front desk of the repair facilities could isolate these alignment issues very quickly. First, you have to figure out if there's user error involved. Then you check cleanliness (two mirrors, hole in the bottom of the mirror box). Once those things are removed, you step through a sequence to figure out which of the pieces is the likely cause of the problem (side-to-side usually doesn't implicate mirrors, but mount and AF sensor position, for example. A Genius would target the necessary fix fast, and doing it in front of the customer would instill confidence in the repair system.
Only problem is that not everyone can get to a Nikon repair facility, Nikon discourages interaction with customers at those facilities, and then there's the dirty secret that some work is farmed out to other repair facilities. Still, my original suggestion years ago was for an ombudsman, and a reachable Repair Genius would be a good substitute.
The Wall Street Journal had an article yesterday on what makes the Apple Stores so successful. They pointed to the Apple Store training manual: "sales associates are taught an unusual sales philosophy: not to sell, but rather to help customers solve problems. "Your job is to understand all of your customers' needs - some of which they may not even realize they have."
Help customers solve problems. That's exactly what Nikon needs to do. If 7% of the units they're seeing at the repair centers are there for focus, and many multiple times, there's a customer problem that needs solving, too. Unfortunately, that customer problem often turns out to be Nikon itself.