The arrival of Canon’s 50 megapixels resolution D-SLRs (see news) raises a number of questions, particularly for the makers of digital medium format camera systems, but also in relation to the current debate regarding mirror-versus-mirrorless.

Canon, like its chief rival Nikon, remains solidly committed to the D-SLR, although the mirrorless tide is definitely coming in on a wave of a steadily increasing choice of products from a group of ‘heavy hitter’ brands. Olympus, Fujifilm, Sony, Panasonic and, most recently, Samsung are all targeting mirrorless models at the professional user and all tout the same key benefits – chiefly smaller and lighter camera bodies and lenses. With the exception of Sony’s Alpha 7 models which have full-35mm size sensors, everybody else is using the smaller ‘APS-C’ or Micro Four Thirds imagers which allow for even more dramatic reductions in the size and weight of the hardware. Thanks to ongoing developments in sensor architecture and the subsequent processing of their output data, these devices are delivering ever better performance even at the higher ISO settings. These imaging performance capabilities are now more than sufficient for a great many applications… certainly for travel, street photography or extreme sports where, of course, the savings in size and weight have obvious benefits. And now that all the mirrorless mounts are pretty well served with dedicated lens systems, another D-SLR advantage is being eroded.

So what is the advantage of having a reflex mirror? Well, for starters, an optical viewfinder. Today’s EVFs are getting very good indeed, but the optical finder is, by default, always going to be superior and, with live view on the monitor, you can still have the benefits of an EVF such as the previewing of capture settings. But is this really enough to combat the allure of the mirrorless cameras? Hard to say which is probably why Canon has decided to up the ante and give its next-gen EOS 5D a 50 megapixels full-35mm sensor. It’s a number calculated to make headlines and it’s likely to be unique to Canon D-SLRs – at least for a while – giving it some all-important leverage against the mirrorless upstarts such as Sony’s Alpha 7R. And 50 megapixels is slap-bang in the middle of digital medium format territory… where a 50 MP CMOS is currently flavour of the month aboard products, both backs and complete cameras, from all the protagonists.

Adopting CMOS-type sensors has enabled issues such as high ISO capabilities to be addressed in digital medium format systems, but check out the rest of the EOS 5DS/DSr spec (fps, focus points, metering zones, video bit rates, etc, etc) and, of course, the extent of the Canon EF lens system. Ahem! The 5DS is best described as being mid-sized so it isn’t exactly compact, but it isn’t particularly bulky either… especially compared to a DMF kit. Soooo… well, digital medium format does still have a key weapon left in its armoury, namely that big… is… er… still better, especially when you see what the Pentax 645Z (tested in this issue) is capable of in terms of image quality or check out the performance of, say, the Nikon D4S at ISO 6400. So we’re talking the fundamental benefits of bigger pixels here (dynamic range, etc), but just as happened with sheet film and, subsequently rollfilm, this is being increasingly outweighed (no pun intended) by many other factors.

The Pentax 645Z is a lot easier to handle and use than you might think, but the idea of lugging any big DMF kit around, especially if it has to be carried any distance (like through any major international airport) is still daunting… and likely to be an issue if you’re travelling on small aircraft.

It’s hardly inconspicuous either – which is becoming more of an issue these days – which is why a little mirrorless camera starts to make more sense in many situations. Mind you, Pentax has trimmed down one important aspect of its medium format D-SLR – the price. In terms of bang for your buck, the 645Z is arguably the best value in any sensor format or camera configuration, although the EOS 5DSr might be about to steal that crown given it’s likely to be priced at under $3000. Or is the size-versus-performance ‘sweet spot’ to be found in mirrorless cameras with full-35mm sensors? Sony has pretty well proved it with the Alpha 7 models and the rumour is that others may follow… how much sense would it make for Canon and Nikon to follow this route? Or what about a medium format sensor in a mirrorless camera… a digital version of the Mamiya 6 or Bronica RF645 perhaps?

The evolution of the camera has always been towards smaller and lighter, and today’s technologies allow both to be achieved without unduly compromising either capabilities or image quality. The mirrorless revolution is actually happening because we want it to – it’s not just a whim of the camera manufacturers – and because, ultimately, more is achievable with fast and lightweight digital cameras, especially when shooting in the field. We really no longer have to feel guilty about not sweating harder – both metaphorically and literally – over our photography… no gain without pain and all that… because technology now does the heavy lifting, leaving us to concentrate more on the creative stuff. So, sometimes, small is definitely better, but then 50 MP resolution in a mid-sized D-SLR may well be the best of all worlds… at least for now.