The Two Opposing Theories of Mirrorless

It’s been apparent for a while that Nikon and Canon have all but killed off the DSLR. Recent reports of Nikon shutting down their F-Mount assembly lines may have been greatly exaggerated, but with each passing year, the odds that we see a new Nikon or Canon DSLR (or even a DSLR lens) are dwindling to zero. Apparently Pentax is still hanging around, and good for them, but the Big Two manufacturers of the DSLR already packed up their suitcases years ago.

The reasons for this are myriad, and luckily for you, this article isn’t another DSLR obituary. But the rapid decline, and eventual death, of the most popular form factor of professional camera in decades – maybe of all time – is the context in which this article arises.

My belief is that there are now two separate, competing theories for what a “mirrorless camera” should be, and the theory that wins will dictate what the next generation of cameras will look like.

Mirrorless digital cameras have been around for longer than you may think, even ignoring point-and-shoot cameras that are technically mirrorless. Leica’s M8 was released in 2006, and Panasonic and Olympus joined them with interchangeable-lens cameras in 2008 and 2009  – years before the first a7 was even a twinkle in Sony’s eye.

But in those early days, mirrorless cameras didn’t hold much of a candle to professional DSLRs, with the possible exception of Leica’s pricey offerings. That changed a bit when Sony announced the a7 and a7R, but even those cameras still felt like unfinished products. The bare-bones lens lineup, painful autofocus capabilities, disappointing handling, and frustrating image quality quirks (like the shutter shock and raw compression artifacts) added up to a platform which exuded unrealized potential.

One huge thing about the Sony a7 and a7R, however, is that they were light. Not just the cameras – the lenses were small, too – and it didn’t come at the expense of sensor size or quality. Tests at the time (including our own) showed that resolution and high-ISO performance were at the same level as a DSLR. In a package that might weigh half as much as its DSLR contemporaries like the Nikon D800E or Canon 5D Mark III, this was an exciting achievement by Sony despite the sacrifices needed to get there.

Portability remained the biggest selling point of mirrorless cameras for years. Even when Nikon and Canon launched their first full-frame mirrorless lineups, this perception held true. Mirrorless cameras like the Nikon Z6, Nikon Z7, and Canon EOS R seemed to be made for photographers who desired light weight. Meanwhile, photographers would stick with DSLRs if they wanted a lot of native lenses, longer battery life, endless buffer capacity, and bleeding-edge autofocus.

But at least the new mirrorless cameras were promising, with a what-you-see-is-what-you get viewfinder and various other improvements, like more advanced video features. Most of all, they were light.

That’s the first theory of mirrorless. A mirrorless camera doesn’t need to beat a DSLR at everything – it could be better at some things, worse at other things – so long as it’s light. If given the choice, customers will pay for a camera that’s lighter than the alternatives, so long as it’s approximately equal in capabilities.

Since then, we’ve seen both Nikon and Canon – and the other mirrorless companies, of course – produce equipment that backs up this theory. Some mirrorless lenses even make significant optical compromises in order to minimize weight. The philosophy goes: weight is permanent, optical issues can be fixed in post. In other words, it’s better to make a lens “good enough” for most photographers, while weighing so little that it becomes almost invisible (and thus they actually carry it along).

However, at the beginning of Nikon and Canon’s journey into full-frame mirrorless, a different theory of mirrorless also started to emerge. Alongside their first Z6 and Z7 cameras, Nikon also announced the massive, all-metal 58mm f/0.95 Noct – one of the heaviest normal primes ever released. Not to be outdone, on day one of the EOS R system, Canon launched the RF 28-70mm f/2L with a constant f/2 maximum aperture and the promise to “bring unparalleled performance” to their new mirrorless cameras.

Why these lenses? Simply put, they were showpieces to indicate what the new lens mounts could accomplish. Removing a mirror doesn’t just get you a smaller camera – it also lets you bring a lens closer to the camera sensor without mechanical interference. On top of that, since both Canon and Nikon could design their mirrorless systems from scratch, they chose to utilize much wider lens mounts than were found on their DSLRs. Optical designs that never would be possible on a DSLR could suddenly be mass-produced for mirrorless – lighter lenses, sure, but also lenses with extraordinary optical performance or unusual specifications. Similarly, on the camera side of things, the lack of a mechanical mirror allowed for technological leaps never seen in a DSLR – features like 20+ FPS bursts and full-width autofocus systems in the viewfinder.

That kickstarted the second theory of mirrorless. They don’t need to be lighter than a DSLR – actually, they could even be heavier – as long as they have more to offer. Weight is one thing, but at the end of the day, customers will pay for the most capable equipment they can afford.

When Canon announced the EOS R3 a few years later – a massive camera with an integrated grip and a DSLR-like form factor – a lot of photographers said that it went against the “mirrorless ethos.” That wasn’t really true. What the EOS R3 actually did was embrace the second theory of mirrorless while ignoring the first. Canon used the huge size of the camera to imbue it with best-in-class features like 195 FPS burst, “photographer’s-eye-tracking” autofocus, and 12-bit raw video.

Nikon likewise embraced the second theory with their launch of the Nikon Z9 in 2021. Like the EOS R3, the Z9 also has an integrated grip and is heavier than almost any DSLR. The form factor is more similar to one of Nikon’s D4/D5/D6 DSLRs than to any previous Nikon mirrorless camera. It was a huge gamble – a bet on the second theory as the future of Nikon’s mirrorless lineup.

The Z9 was overwhelmingly successful. It injected excitement into Nikon’s relatively stagnant line of mirrorless cameras at the time and reversed a lot of negative commentary about the brand. When the same tech trickled down to the more affordable Nikon Z8 – itself about the same weight as a DSLR like the D850 – the positive comments continued.

You’ll notice how, since then, more and more of Nikon’s lens announcements have followed the same pattern. They’ve launched groundbreaking, high-performance equipment that doesn’t concern itself with every last gram of weigh. The Z 135mm f/1.8 Plena may be the most obvious example – as you’ll see in our upcoming review, it is one of the best lenses ever made from an optical standpoint, but it’s hardly small and light.

This all follows the second theory, which says that customers will pay for the most capable equipment that they can afford. Granted, “affordable” is still the big question with some of this gear, but Nikon’s recent success has proven nonetheless that many photographers favor capability over portability. Nikon’s bet on the second theory seems to have paid off.

What has Sony done in response? For the most part, they are continuing to embrace the first theory. Sony has yet to release a mirrorless camera with an integrated grip, and even the flagship Sony a1 is about the same size as any other mirrorless camera. Likewise, the company’s newest lenses, like the FE 16-35mm f/2.8 GM II announced last year, are all about saving weight.

So far, this approach has worked well for them – Sony has held onto a massive market share despite going up against the full attention of Nikon and Canon. Not to mention that their cameras and lenses make convincing arguments that smaller gear can be just as good as bigger equipment. (Witness the Sony a1 versus the Nikon Z9, which is a pretty level comparison, although the Sony a1 is admittedly $1000 more expensive.)

As for Canon, they seem to be more torn than Nikon or Sony at the moment. Their EOS R5 famously had overheating issues due to its impressively small size, which is a classic example of the tradeoffs inherent in the first theory. Canon has also been more willing to embrace digital lens corrections than either Nikon or Sony, especially when it comes to vignetting and distortion – tradeoffs they accept in order to keep their lenses smaller, even though it hurts some of their reviews.

However, Canon’s more recent efforts indicate a gradual embrace of the second theory, too, following much the same shift that Nikon did. Their upcoming EOS R1 flagship camera will have an integrated grip and will likely be Canon’s heaviest mirrorless camera yet. Meanwhile, some of their newest lenses signal the same approach, such as the recently-announced RF 24-105mm f/2.8L – a heavy but groundbreaking lens. Whether we will see them continue down this path, or perhaps try to have it both ways, remains to be seen.

That sums up the dichotomy as I see it today: Lots of mirrorless equipment continues to prioritize light weight, but increasingly often, camera companies will forego that goal as they chase maximum performance.

Of course, the future hasn’t been written yet. The second theory might be gaining ground right now, but I can’t say that it will last forever. Capability looks good when you’re buying a camera; portability looks good when you’re carrying it with you. There’s a reason why the real winners of this argument have been smartphone cameras (harkening back to Kodak’s portable cameras winning the race in the 1900s). It’s a small part of the general public who even knows what mirrorless ILCs are in the first place, and that probably won’t change.

Even so, I think it will make a big difference to the fortunes of Nikon, Canon, and Sony – and to a lesser extent, Leica, Panasonic, Fuji, and OM System – which theory they choose to embrace. Of course, there’s no rule saying that a company can’t aim for both – or go a totally different direction entirely, like retro or modular cameras – but market realities dictate that something will take priority for each camera and lens manufacturer. Whoever correctly predicts the tug-of-war between portability and performance has a lot to gain in the coming years.

I’m curious, which theory do you prefer? And which one do you think the different camera companies will embrace? I find that my personal goals as a photographer have cycled over the years, starting with chasing maximum quality, then minimum weight, and now back in the other direction. But every photographer is going to be different, which is why this problem is so difficult for camera companies to solve. Let me know what you think in the comments section below.