What’s the deal with the Canon 70D?

2 Jul

Canon has just released its new mid-range APS-C camera, the 70D, following on from a line-up traditionally situated between the entry-level “rebels” such as the 700D and the more recent flagship, the 7D. But rather than look at the new camera’s position in the line-up, let’s explore its features.

For some time now, Canon has continued to produce great glass alongside cameras with mediocre sensors. Particularly, Nikon has overtaken in terms of resolution, sensitivity/noise and dynamic range, the latter being particularly hurtful to Canon’s reputation, utility, and business.

Canon EOS 70D

Promotional image of the 70D from Canon

Along comes the 70D – what can we expect? It’s clear that Canon has made this model matter, placing it as a deliberate game-changer with all the features thrown in that could win it top awards in reviews – a swivel and touch display of high resolution, a tiny increase in capture resolution for still images, and WiFi connectivity. This alone won’t be enough to silence the critics, since, as Samsung recently reconfirmed, what matters most to people is the quality of the resulting image. Image quality could be said to consist of a combination of resolution, sharpness, dynamic range, and colour and brightness fidelity. Unfortunately, with the camera having just been announced, we may have to wait a little to see if the new sensor can deliver improvements in any of these areas.

The headlining feature, however, will be its on-sensor phase detection technology, which, in contrast to previous such attempts, allows examining sharpness at each pixel within an 80% window of the overall frame. I have to admit that while this is an improvement on all current implementations of on-chip phase detection autofocus, it rather reminds me of Canon’s dogged determination to give its users an inferior 95% frame coverage pentamirror viewfinder, where Pentax gives you 100% view at entry level – and even the 70D delivers only 98%. But enough of partisanship – I rightly shot down Canon’s 100D as a gimmick, and will give credit where it’s due. That said, it will be difficult for Canon to convince me that they’ve obsoleted the optical viewfinder by providing an admittedly versatile rear display.

Canon EOS 70D with active WiFi link

Canon promotional image showing active WiFi link in top display

Canon is clearly keen to get the word out and salvage what fans haven’t averted their eyes, minds and wallets at the over-two-year lag in sensor performance. The EOS M hasn’t made a huge impact either, so what can the 70D bring?

There is no word yet on how fast this new live view autofocus is, and remember that it competes with a 19-point traditional phase detection autofocus that is active when using the optical viewfinder. The statement seems to be that the on-chip autofocus is preferable, as it evaluates many more focus points than the traditional sensor. However, the same DIGIC 5+ imaging processor that fulfils a more traditional role in the 5D Mk III seems to have been tasked with this new load, and is presumably slowed down by it, much as the Pentax K-5 II, according to some test data, is struggling to provide snappy autofocus amid the new AF sensor capabilities and presumably CPU-intensive algorithmic improvements.

I would therefore expect the on-chip autofocus to be slow. This, presumably, is the reason why no electronic viewfinder was provided, leaving the 70D as a bit of a half-way horse, and explaining why these advances weren’t introduced in a flagship model. I suspect the best route for interested users would be to wait for test data, and probably a successor model that perhaps leverages a DIGIC 6 or 7 for fast on-chip phase detection autofocus and electronic viewfinder. If such a combination could result in less AF hunting and fewer false catches or “snags”, it would be a true revolution deserving of amateur investment. (But pick your lenses carefully because the optical stabilisation – denoted IS or IS II in Canon jargon – is still going to cost you a lot extra!)


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