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An analysis of EOS-1D Mark IV autofocus performance
Thursday, February 11, 2010 | by Rob Galbraith
It has been almost three years since the announcement of the EOS-1D Mark III, a camera that was meant to extend Canon's dominance among one of its core constituents, the news and sports photographer. But troublesome autofocus and a resurgent Nikon teamed up to make the EOS-1D Mark III anything but a happy commemoration of 20 years of EOS back when that model was unveiled on February 21, 2007.

During its lifespan the EOS-1D Mark III was subject to multiple calls back to Canon service to correct both hardware and AF calibration errors, plus the company issued several autofocus-related firmware updates in an attempt to shore up the camera's AI Servo tracking performance.

In that same year Nikon unveiled the D3, offering what is arguably the company's best AF system to date. For Canon, Nikon's new camera couldn't have come at a worse time, since it offered a way out of the autofocus mess of the EOS-1D Mark III for frustrated Canon sports shooters. At least those with deep enough pockets (or employers with deep enough pockets) to make the brand switch.

The EOS-1D Mark IV, released in small quantities towards the end of December 2009 and shipping in somewhat greater volume now, is meant to erase the memory of the design, manufacturing and quality control problems that plagued its predecessor. It's also meant to once again put Canon's flagship action camera on a competitive footing with Nikon's newest digital SLR, the D3S, and do so in time for the start of the XXI Olympic Winter Games (which kick off tomorrow in Vancouver, Canada.)

Thin Ice: Canon EOS-1D Mark IV (firmware v1.0.6) + EF 400mm f/2.8L IS, ISO 6400, 1/1000, f/2.8. Click photo to enlarge (Photo by Rob Galbraith/Little Guy Media)

The EOS-1D Mark IV is outfitted with a new 16.06 million image pixel sensor as well as a host of secondary refinements, but it's a fair guess that Canon's biggest engineering effort went into revamping the new camera's autofocus capabilities. It might seem to be a close cousin of the AF system in the EOS-1D Mark III, and indeed it shares the same 45 point arrangement and a comparable slate of configuration options (with some smart new options too).

The AF system similarities are skin deep, however. In just over a month with the new model we've seen that the EOS-1D Mark IV's AF system behaves almost nothing like that of the EOS-1D Mark III. The changes that Canon's autofocus engineers have made are both broad and deep.

But, do these changes make the EOS-1D Mark IV's AF system better, particularly for shooting a variety of outdoor and indoor peak action sports in AI Servo AF mode? More importantly, do these changes make the EOS-1D Mark IV a viable option for the sports shooter who depends on solid, reliable autofocus to get their job done?

That's what we set out to determine since our first EOS-1D Mark IV body - one of five production-level units we've shot with since then - arrived early in the new year. Site co-editor Mike Sturk and I have photographed basketball, speedskating, hockey, soccer, track and more, plus controlled tests that carry over from when we collaborated with Canon on the EOS-1D Mark III about 2.5 years ago.

EOS-1D Mark IV AF: signs of brilliance, but...

Locked On: Canon EOS-1D Mark IV (firmware v1.0.4) + EF 300mm f/2.8L IS, ISO 200, 1/8000, f/2.8. Click photo to enlarge (Photo by Rob Galbraith/Little Guy Media)
We'll get right to the point. The EOS-1D Mark IV's AF system shows signs of brilliance. For example, while testing the camera's ability to track an athlete running straight towards the camera, the EOS-1D Mark IV locked onto the subject and would not let go, producing sequence after sequence of mostly in-focus pictures. In several rounds, 25 or more frames in a row were either perfectly focused or just slightly out.

On the same track and under effectively identical test conditions to those that tripped up the EOS-1D Mark III's AI Servo AF every time, the EOS-1D Mark IV nailed it.

Move past that simple AF test, however, and the EOS-1D Mark IV autofocus picture becomes blurrier. Here's what we've encountered:
  • At speedskating, the camera managed a healthy number of in-focus frames of skaters rounding the corner, but coming down the straightaway towards the finish, and beyond the finish (where the winners will typically pump their fists), the results were mixed to poor. Too often the EOS-1D Mark IV would frontfocus significantly or, alternately, appear to stop autofocusing altogether.

    Through over 150 pairs of fast 500m and 1000m skaters, as well as skaters in the slower 5000m event, the camera at times rose to the occasion, netting 10+ consecutive in-focus frames in a sequence with some competitors. At other times it would misfocus for almost as many frames.

    Particularly puzzling was the camera's behaviour once the race was over: as skater after skater stood upright just past the finish, the camera would lose focus and sometimes not recover. If we had been photographing real races and not time trials it would be the point where the winners celebrate. This is not a good moment for the AF system to act up.
    Going Up: Canon EOS-1D Mark IV (firmware v1.0.6) + EF 70-200mm f/2.8L IS at 80mm, ISO 200, 1/500, f/6.3, Dyna-Lite Arena strobes. Click photo to enlarge (Photo by Rob Galbraith/Little Guy Media)
  • At basketball, the EOS-1D Mark IV didn't rise above the level of fair-to-middling. It made in-focus frames in both available light and strobed shooting - including some frames we're happy with, such as the one at right - but it missed about as many frames as it got.

    When looking at the available light photos, it was apparent why: like speedskating, the EOS-1D Mark IV was too often shifting the focus way out in front of the subject. At other times, the focus was inexplicably drifting behind. After six games, what the pictures show is a camera that's neither very good nor terrible at autofocusing the sport of basketball.

  • The EOS-1D Mark IV's autofocus performance through 4.5 games of soccer was bizarre.

    We've shot two games - one as night began to fall and the other lit only by high school stadium lighting - in which the AF system worked quite well, locking in on key moments, capturing many in-focus frames in extended sequences and generally doing about as good a job as we could hope for given the conditions.

    We've also shot one late afternoon game, and half of another with a mix of low sun and stadium lights, in which autofocus performance was just so-so. There were some crisp moments and decent sequences but also an unacceptable number of frontfocused frames as well as a few backfocused ones, much like basketball (though the overall take was somewhat better than basketball).

    Rounding out the soccer experience was one game in which the AF system verged on total collapse, much like the EOS-1D Mark III in its early days. The game took place on a beautiful sunny morning and the play was frontlit, meaning that conditions were not what we'd consider strenuous for autofocus. Curiously, the EOS-1D Mark IV's autofocus improved when the sun went behind a cloud at several points. By comparison, its autofocus fell off a cliff when the sun was out and the players in red jerseys were being photographed.

  • Weather conspired to prevent shooting as much track as planned, but we did do enough to make a few observations:

    • First, the camera body and lens (an EF 400mm f/2.8L IS) that performed so poorly at the last soccer game mentioned teamed up a little later that same day to perform generally well at track, including while shooting hurdles from a slight side angle, which is something we've seen other cameras' AF systems stumble on.

    • Second, during fast heats, with runners coming straight towards the camera, the EOS-1D Mark IV tracked superbly, much like the runner tests.

    • Third, the camera is always ready to frontfocus or backfocus when provoked, and while this was in evidence at track it wasn't a significant problem except perhaps during long jump.
Add it all up and the conclusion is inescapable: the EOS-1D Mark IV has an AF system that is capable of greatness but is also so bewilderingly variable that there's no way to trust it, especially for outdoor sports. Indoors, EOS-1D Mark IV autofocus performance has been less variable, but our results from speedskating and basketball are simply not up to par. If this is the best the company could muster, after the autofocus debacle of the EOS-1D Mark III, then it's official: Canon has lost their autofocus mojo.

You'll find downloadable example pictures at the end of the second page.

One article becomes two

The conclusions we're drawing about EOS-1D Mark IV autofocus aren't happening in a vacuum. We're looking at the photos we've shot with two questions in mind:
  • Does the AF system deliver enough in-focus peak action sports pictures for the camera to be usable?

  • How well does the AF system stack up against other options with which we're familiar?
While writing about the EOS-1D Mark III and its AF system, we continually made comparisons to the EOS-1D Mark II N. This time around, we set out to pit the EOS-1D Mark IV against Nikon's D3S and to combine an analysis of the new Canon's AF system with a comparison of that system to the 51-point Multi-CAM 3500 inside Nikon's flagship news and sports camera.

Competition: A photographer and his Nikon D3S at the Olympic Oval in Calgary, Canada. Click photo to enlarge (Photo by Rob Galbraith/Little Guy Media)

To that end, much of what we've shot with the EOS-1D Mark IV, including the runner tests, speedskating, basketball and more, was also shot with the D3S. Mostly with Mike Sturk and I sitting side by side, capturing sequences of the same thing at the same time.

The plan was to roll those comparison sequences into this article, along with an overview of Nikon autofocus and some general conclusions about how the AF systems compare. It became necessary to modify that plan when Canon released firmware v1.0.6 for the EOS-1D Mark IV, an update whose only stated change was to AI Servo tracking. This meant having to redo much of the shooting we'd already done with the EOS-1D Mark IV, which in turn meant it was then impossible to meet our deadline for this story, ahead of a period of heavy travel, and include all of what we had wanted to about Nikon.

That will come in another story to follow, a bit later in the first half of this year. For now, here are a few thoughts about Nikon D3S autofocus and how it holds up against EOS-1D Mark IV autofocus.
  • In the blue singlet runner tests the EOS-1D Mark IV is consistently better. The D3S does really well too, flubbing only a few frames in extended sequences, but the EOS-1D Mark IV is capable of getting every frame in focus. While it doesn't do this every time and it doesn't do it in every kind of outdoor daytime light, it does deliver nearly perfect focus often enough in this test to edge out the D3S.

  • The D3S is an awesome basketball autofocus camera. From a higher level position with an AF-S VR NIKKOR 300mm f/2.8G IF-ED or AF-S NIKKOR 400mm f/2.8G ED VR on the front, we've shot games with the D3S (and D3 and D700) where the camera refuses to miss. From court level, with the new AF-S NIKKOR 70-200mm f/2.8G ED VR II attached, the number of in-focus frames has been higher than we've achieved with any other camera/lens combo ever. The EOS-1D Mark IV isn't in the same league as the D3S for this sport.

  • The D3S is the best camera we've used to shoot speedskating, though there's also room for improvement.

    First, it's hard to fairly compare any two cameras and their ability to track a skater rounding a corner, because the photographer's skill at keeping the AF point or group of points on the skater is as big a variable as the camera's AF system, particularly when shooting tight with a 400mm lens. What we do see is that the D3S' outer AF points work surprisingly well, given they're not cross-type, and that it, along with the EOS-1D Mark IV, makes a decent number of properly-focused frames.

    Down the straightaway towards the finish line and beyond, however, the D3S is superior. It's consistently more forgiving than the EOS-1D Mark IV when the selected AF point drifts off the subject momentarily, even when the speedskater's motion is noticeably side to side (no two skaters are alike in this regard and the ones that move to and fro are always difficult to keep properly targeted). Plus, with the D3S we haven't seen the frustrating loss of focus that has occurred with the EOS-1D Mark IV when the skater stands and glides after the finish.

  • The D3S is a very good soccer autofocus camera. It misses here and there when it ought not to, and we've run up against a problem in which the camera will at times frontfocus slightly in bright light. Because of these things we're stopping short of calling the D3S great at autofocusing this sport. Overall, though, it has been darned good.
Lights Out: Nikon D3S + AF-S NIKKOR 400mm f/2.8G ED VR, ISO 12800, 1/800, f/2.8 (Photo by Rob Galbraith/Little Guy Media)

The EOS-1D Mark IV's Jekyll and Hyde autofocus performance at soccer has been so wacky that it's difficult to make a comparison to the D3S. All we can say is that the Nikon AF system has been far more consistent and predictable than the EOS-1D Mark IV when photographing soccer.

The D3S is a fine sports autofocus camera, though it's not without its quirks and, as mentioned, there may well be something not quite right about how it tracks with a long lens in bright light.

It's worth noting one other fundamental difference between the AF system in the D3S and that of the EOS-1D Mark IV. When Nikon focus is out, it doesn't tend to be way out. More often than not, peak action frames that are not perfectly focused aren't that blurry, making some of them still viable. That is, if you're of a mind that it's better to have a slightly soft frame of a great peak moment than a totally blurry one. The EOS-1D Mark IV, on the other hand, produces many more frames that are too soft to use for anything, no matter how sweet the moment.

To sum up, our experience with the D3S' AF system is that it's trustworthy and dependable enough for us to be confident using it for peak action sports. Not perfect: it needs to be a bit faster off the line, in addition to the other quibbles we've mentioned. But it does work as needed most of the time, which is in stark contrast to the experience of the EOS-1D Mark IV in the last month.

We'll delve into Nikon autofocus more deeply in a future article. On the next page you'll find links to downloadable bundles of EOS-1D Mark IV pictures of soccer, basketball, track, speedskating and runner tests, plus detail about the bodies, lenses and camera settings we've tried.
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