The best-selling camera with 8 buttons, in the western Tri-state area, last Tuesday between 11:47 and 11:49.

"We're #1 in full frame*," scream the press releases from the three big full frame camera makers. And, given the price and apparent appeal of the Sony a7 III, I wouldn't be surprised if there's more screaming once it hits the shelves.

The precise wording changes, as does the length of the list of caveats that follows that all-important asterisk but, I'd argue: what doesn't change is that it's simple boosterism. And you should pretty much ignore it.

There are a couple of reasons I say this. The first is that, even if you take all the footnotes (in this month, in that territory...) into account, the numbers don't really tell you very much.

These announcements mainly tell you whose turn it is to be king for the day

Part of this is because you're cherry-picking data from a small sample: there are only three big brands in the sector and very few products being launched. This means the launch of a new model inevitably causes a sales spike and this can see one brand jump in front of the others in the sales chart. A new model will sell more through pre-orders than an existing competitor that, post launch spike, has been selling steadily for 23 months. So, rather than saying which camera is king, these announcements mainly tell you whose turn it is to be king for the day.

Existing commitments

It's interesting, of course, when similar models, such as Nikon's D850 and Sony's a7R III get launched around the same time. But even though they are targeted at pretty similar customers, the winner of the sales race doesn't tell you much about the cameras because there's already a degree of brand loyalty baked into the market.

Investment in lenses and accessories means that anyone already shooting full frame is very unlikely to switch systems. So, if we assume a good proportion of new full frame sales are being made to exactly these photographers, you realize much of the current popularity was defined years ago.

And this doesn't just apply to people who're already shooting full frame. The manufacturer-promoted (though arguably mythical) concept of the upgrade path can lead to people feeling committed, or to commit themselves to a system, even if they aren't shooting full frame.

There's tremendous inertia to overcome before any brand can make headway in the pro sector. Even once Sony's 400mm F2.8 becomes available, it's not going to displace all those Canon 'L' lenses overnight.

All these issues are amplified at the high/pro-end of the market. Not only are many pro-orientated lenses much more expensive, thereby increasing the financial commitment to a system, but there's also a chance that some of your kit belongs to your employer or that you're already a member of one brand's pro support network.

So a lot of sales figures are more about whether a brand has convinced its existing user-base to modernize/upgrade, rather than about stealing customers away from other systems.

Further inertia

To cause any significant amount of brand switching a camera would have to be compellingly better. And people have to recognize it.

Canon stole a huge march over Nikon in the early days of autofocus and the sea of white lenses that flanks the sidelines of sports games are a testament to that, as much as anything else. Canon could release a stinker (or, in the case of the EOS-1D III, a camera that develops the reputation as one), but that's not going to drive customers away unless they release a series of duds and the competition is doing something noticeably better. Again, this counts double for professionals.

To cause any significant amount of brand switching a camera would have to be compellingly better. And people have to recognize it.

Even if one brand does fall behind, its users may not notice. For a while Canon lagged behind in dynamic range, but that didn't see any mass exodus because many Canon shooters, having not experienced the difference and having adapted to the capabilities of their existing cameras, simply didn't notice. After all, you can't miss what you've never had. So it's unlikely many Canon photographers felt any impetus to switch, even though there was a real-world photographic benefit to doing so. Now that Canon has essentially closed that gap and opened up a new front with the development of Dual Pixel AF, the moment has passed.

So while we felt the EOS 6D II was a bit disappointing, compared with its rivals it's still good enough that existing Canon buyers will stick with 'their' system and perhaps never be aware that the grass might be greener just one field over.

Until the fog clears, it's all bluster

Which is to say: these numbers don't tell you anything at all about how good the respective brands' cameras are.

They might tell you something interesting about whether a new technology is finding a foothold in the market, but without a lot more context, it's hard to meaningfully interpret even that. For instance, no matter what Sony proclaims, it'll probably take a few more years to establish whether mirrorless is making inroads into DSLR sales or to what extent it's simply expanding the market.

These numbers don't tell you anything at all about how good the respective brands'
cameras are

I can see that sales success of the system you've bought into can give some reassurance that it has a future, but should you care about how one brand is performing relative to another? Since the numbers tell you next-to-nothing about camera quality or even much about what's happening in the market, I'd argue most discussion of sales rankings are simply fanboyism. And the canny stirring of it by marketing departments.