Mirrorless telephoto

So despite being fully bought into mirrorless cameras, I still have a Canon 7D hanging around. This is now used as a dedicated telephoto camera, mainly for moving targets, and the only two lenses that have survived the move to mirrorless are the Canon 70-200/4 IS and the Canon 400/5.6.

These are both good lenses, and no other camera I currently own can compete with the 7D for tracking moving subjects, see previous Panasonic GH3 comparisons, but it would be nice if I could get rid of the 7D and have similar performance from a smaller and lighter mirrorless camera.

Canon alternatives

The two main candidates would be the the Olympus E-M1 and the Fujifilm X-T1, both of which have on-sensor phase detection pixels. The E-M1 can manage up to 6.5fps, and the X-T1 up to 8fps, compared to 8fps on the 7D[1].

So maximum speed is there or there-abouts, and I would gain from having a much smaller and lighter body. The 7D weighs 860g versus 500g for the E-M1 and 440g for the X-T1.

Both Olympus and Fujifilm have interesting telephoto zooms coming out. I’m working on the assumption that all these options are good enough in terms of image quality.

Canon 70-200

Fujinon 50-150

Olympus 40-150





35mm DOF




35mm focal length




Physical length (mm)




Lens weight (g)




The Olympus combination has the best range and is F2.8, but it has a smallest sensor. As a rough estimate I consider each step in sensor size from MFT to APS-C to FF to be worth about a stop of noise performance, presuming cameras at the same point in the technology cycle, i.e. for low light performance the E-M5 at F2.8 should be similar to a APS-C camera at F4. Except the 7D is much older so I’d expect the E-M5 to be a stop better in light gathering[2].

The Fuji combination has the shallowest DOF, and the best low-light having a F2.8 aperture combined with a larger, modern sensor. But it is a bit short in reach compared to the others. If we add a, hypothetical, teleconverter that brings it up to a similar range but then it’d be F4 anyway, making it equivalent to the Olympus.

This is all just a long way of saying that on the lens side there’s no difference between the systems. These are three lenses of similar physical size, similar weight, and assuming a teleconvter on the Fuji, similar low-light performance and similar DOF.

No threat from without

So switching to mirrorless saves nothing on size or weight on the lens side. Whilst the bodies are lighter, when combined with the lens the difference isn’t that great.




Camera weight (g)




Lens weight (g)




Total weight (g)




The Canon combination is still the heaviest, but only by 12-15% compared to the mirrorless options. That’s something, but hardly revolutionary. As the lens lengths are similar as well all combinations are going to be a little unwieldy and require a more serious camera bag. So not really any convenience gain.

I’d also take a financial penalty for changing systems, the new lenses will be no cheaper than the Canon 70-200, and the tracking performance is likely to be only be as-good but not better.

Finally, switching would also mean I’d have to get rid of the orphaned 400/5.6, which whilst rarely used, is just brilliant sometimes.

No threat from within

But if the 7D isn’t under threat from mirrorless cameras, it’s not likely to be replaced with its successor, the newly announced Mark 2 version. The new 7D2 is a very conservative product, a few more pixels, a bump to 10fps, and GH3 level video. I’m sure it’s a better camera, but not enough to be tempting.

There’s life in the old 7D yet.

  1. The 7D came out in 2009, so the mirrorless universe is taking its time catching up. The pro-level 1D2N came out in 2005 and managed 8.5fps [Back]
  2. Having said all of that, light gathering is rarely an issue with my use. Most situations where I use the 70-200 are in daylight, where fast shutter speeds are possible even with low ISOs. No combination here is good enough to use in genuinely low-light situations [Back]