A few days ago, I was invited to an event organized by KTM's Greece dealer, where they presented the new generation of MX (Motorcross) KTM bikes. At this point, many thanks to my buddy, Nikos Vitsilakis as well as Kostas Kalantzopoulos and the great people of KTM Greece for this opportunity!
I thought of exploiting this experience for testing the performance of a couple of mirrorless cameras , in action shooting. But first a disclaimer.
Shooting motorsports involves much more than jamming the shutter and shoot at a million fps. Spray and pray doesn't cut it; as with any photographic discipline, you have to know your subject. Experience is a must.
That said, although I've shot a lot of Rally races, both photos and video, this was more than 10 years ago, with vastly different resources and under different conditions. All that, to declare that I'm completely useless at shooting bikes motorsports; as I soon found out, the problem is not with the equipment, but with the idiot behind the camera. So please accept my apologies for the samples presented here...
Dirt-track bike racing is pretty tricky to shoot appropriately: bikes sometimes appear from nowhere, disappear behind natural obstacles and generally jitter around a lot. It's technically challenging both for the photographer and the camera to hold focus and frame in a useful manner.
It has long been claimed that mirrorless is still not "up there" with the best DSLR for sports shooting, so it was an opportunity to check this claim, given all the drawbacks I described above. I had the E-M1, with the M-Zuiko 75mm f/1.8, and the X-T1, with the kit 18-55mm f/2.8-4.0, so I gave them a go. Here is my experience.
The E-M1 was used at C-AF+tracking mode. I found out that it could get initial focus on the target quite quickly, albeit with some "hesitation". From there on, it was able to hold focus easily, I was able to get almost 100% hit rate in most conditions, with 80-85% being easy. Check for example the series of shots below, for a "real life" sample. As mentioned before, see that my trouble was in keeping the appropriate framing (Olympus E-M1, Zuiko 75mm f/1.8, @f/2, ISO 200, 1/3200):
My complaint about the E-M1? It tends to lose focus if anything tries to get between it and the initial target, like, for example, another bike.
Although the X-T1 was somewhat in a disadvantage, by not having any of the faster system lenses, it also performed without serious issues. The camera was equipped with the latest (Ver. 4.0) firmware, which finally offers quite useful tracking capabilities. After a little experimentation with focusing area, it was also able to acquire and hold targets easily. Here my main issue was not with the tracking, but with the X-T1 buffer size: it's great if you only shoot RAW or only JPEG, but gets filled quite soon if shooting both, which resulted in missed shots due to shutter delay.
Overall, I managed to get some shots that I really liked. My evaluation? As a novice sports shooter, I cannot say if current generation mirrorless are "up there" with sports DSLRs or not. Only that I found very little in terms of technical problems in shooting them in such an environment. I suspect that an experienced user could easily get good results much more easily than myself.
This is not to say that there is not a (serious) area for improvement. Although both cameras remained fairly responsive in use, my impression is that, "action mirrorless cameras" are not that much limited by the AF technology per se, as they are by appropriate (powerful) processors dedicated to such routines. There is a reason top DSLR sports cameras, such as the Canon 1Dx, have twin processors. The AF system has to be independent from other camera processes, and there is definitely a need for large and fast buffers, even with today's very fast SD cards.
When even cheap smartphones boast ultra-powerful CPUs, I think it's possible, by use of electronics miniaturization, to offer high-end performance in future flagship mirrorless cameras. I'm sure that newer technologies, such as the next version of Panasonic's Depth From Defocus (DFD), coupled with more powerful processors will answer once and for all the "action/sports mirrorless" question.