We don't tend to trade in internet rumors around here: there are too many half-truths and too many un-truths floating around out there to make it worth our time to try to get to the bottom of them. But when a manufacturer launches an ad campaign designed for the sole purpose of fueling rampant speculation, it's hard not to wonder what's up. Scan of the Rangefinder ad from Echenique.com, via NikonRumors.com Nikon placed the above ad, which has been making its rounds on the internet in scan form ever since, in the August issue of Rangefinder magazine, touching off an inferno of speculation in certain corners of the internet. And why not? With claims like, "Something SO BIG we can't even tell you what it is," the ad is really nothing short of incendiary. Usually furtive Nikon flaunting the fact that they're up to something (something BIG, as best I can tell) is strange in its own right. And in spite of the ad's promise that more would be revealed "next month" – that is, September – more than two months have now come and gone without any additional substantiation. So what's Nikon planning? With no reliably sourced information to work from, speculation has been cleared to run free. And from this ad, the rumor that Nikon is preparing to go where no mainstream consumer manufacturer has successfully gone in the digital era (incidentally, Pentax gets points for coming the closest) and launch a medium-format digital system was born. The MX format mysteryIn fairness, other information to support the claim that a medium-format body is the "BIG" thing that Nikon is up to has emerged. PhotographyBay.com, one of several sites that have become clearinghouses for information on the forthcoming product, reported early on on a document that listed three sensor sizes/formats for Nikon DSLRs: DX (APS-C sensors and digital-only lenses), FX (full-frame sensors and lenses), and the previously unknown MX format. Digging a little deeper into admittedly unverifiable sources on the subject of MX format has suggested that the new big thing that Nikon is working on is a relatively compact medium-format system (not unlike the recently announced Leica S2) with a 40.7 megapixel sensor. So could this, a compact medium-format camera, be the big as-promised announced? In terms of pure technology at the level of body development, there's nothing especially unreasonable about the idea. Medium-format sensors are usually much less proprietary than their smaller counterparts, and cramming all of the necessary components into something roughly the size of the current D700 as rumors have suggested is not out of the question. But the problem with this line of thinking as I see it is that a single ad has now provided the lynch-pin for (and perhaps even the impetus behind) this whole web of partially informed speculation. Without that ad – which makes no mention of anything revolutionary, but only of something "BIG" – none of the other pieces of evidence presented in support of a new medium-format camera stand at all strongly on their own. Sure, a medium-format system would be big from a technological standpoint, and certainly big on resolution besides. But I can think of other, much more conventional things that Nikon might be planning for next February that would also be fairly described as big. Moreover, there are other serious considerations that don't bode well for a Nikon medium-format system in the near term. The lens dilemmaThe most pressing unaddressed problem with the MX rumor as I see it is also one of the most fundamental: where do the lenses for such a system come from? Persistent blog rumors that a new Nikon MX system would be able to, through some combination of contrivances, use Nikon FX glass have been thoroughly debunked by those who understand the mechanics involved in designing optics for larger sensors. Simply put, the physics of it don't work. So if not from the current stock of Nikon full-frame glass, where would the lenses for an MX camera come from? Unless Nikon entered some mount licensing agreement (which seems unlikely to me), optics for the new system would have to be purpose-built by Nikkor and launched with the body. As if on cue, a list of six forthcoming MX-format lenses from Nikon/Nikkor has also bobbed to the surface from some murky internet backwater. But the fact that "official" documents are too easy to fabricate notwithstanding, the lens development issue is really what kills the credibility of an MX system camera in my mind. Although it owns a large share of the consumer and professional camera markets, compared to many of its competitors – what with their attachments to large general imaging companies or consumer electronics firms – Nikon is a fairly small operation. While most of its competitors in the medium-format space are also small, they didn't try to build systems from the ground up. Rather, they've adapted existing film technology over time. On the optics front, Nikon has no such safety net – only its familiarity with DX and FX optical design to work from. The thought, then, of a firm of Nikon's size gambling on the development of this many new (and expensive, in terms of both development and production cost) lenses for an unproven system in a niche market seems more and more outlandish the more you think about the business side of it. Certainly not impossible – manufacturers have done more outlandish things than this before – but arguably not a great business decision, either. Alternatives to MXThe obvious, if somewhat more conventional, answer about what Nikon's doing in response to the "BIG" ad seems straightforward enough: D3x. Given the launch date and venue, it seems most likely (to me, anyway) that Nikon is prepping a high-megapixel "studio" version of its D3 – just like it did with the D2 a generation ago. No, it's not as exciting as the MX format hype, though I doubt that it will be a snooze from a technological standpoint, either. If you were to speculate about what Nikon's now infamous ad might imply in absence of any of the supposed evidence for an MX format camera that has been unearthed on the internet, a D3x would be the most logical informed guess based on Nikon's past history. My position: wishful skepticismLike probably every other imaging industry watcher on the planet, I'll be elated if it turns out I'm wrong: in fact, I really hope I am, as Nikon's move (especially if it was competitively priced compared to existing technology in this space) into medium-format imaging will only serve to make the possibilities of huge sensors seem more relevant and more accessible to those who find the rarefied air of the current medium-format market a little stifling. But based on what we've seen so far, I'm holding my ground as an "MX format skeptic" until something more convincing than a few lists, a cryptic translation, and some small, blurry photos shows up. Round Up is a regular editorial column on DigitalCameraReview.com.