For the years 2009-2011, it is based on the 20 most selling camera models in Japan, including DSLR cameras. For 2012-2013, it is based on the 20 most selling mirrorless cameras. For 2014, it is, apparently, based on all mirrorless camera models. I skipped 2008, since it only contains one single mirrorless camera, the Lumix G1, giving a 100% Panasonic market share.
Panasonic got a head start. After all, they were the very first movers in this market, with the G1. They were quickly overtaken by their partners in Micro Four Thirds, though, Olympus. Olympus had a big hit with their retro styled cameras, especially their OM-D camera models with built in EVF.
Olympus is seeing some changes to their market, though. The E-Pn line of "PEN" models used to be popular, but is seeing less sales. The most recent PEN E-P5 is probably the last of the series, as the PEN Lites take over, with a similar feature set and a lower price.
Sony launched an impressive number of different NEX models, frequently updating their feel and functions. While their first cameras did look rather strange, their more recent models appear more like "normal" cameras. Their premium APS-C camera uses PDAF technology to achieve very quick and precise autofocus, also for moving subjects. The pancake kit lens is not very good, though, see my test here.
Recently, Sony has ventured also into the fullframe market, with their A7 models, which are compact and priced fairly modest. However, the fullframe lenses are still quite large and expensive.
With a very expensive marketing budget, Nikon got a good start with their "1" mirrorless format. However, it is difficult to sell fairly large, expensive cameras with poor ergonomics and a small sensor.
As it turns out, the Nikon 1 system has three strengths, in my opinion:
- Very good implementation of PDAF from the start. When I tested the first generation entry model Nikon 1 J1, I found that it had vastly better autofocus performance than the later and premium priced Lumix GM1.
The PDAF technology implemented means that you get very good autofocus performance during video recording, and, probably more essentially, for moving subjects in AF-C mode. The Nikon 1 cameras can rival high end DSLRs in this area. This autofocus performance is the most important when using long lenses.
- Very fast framerates. The Nikon 1 cameras can take 60 frames per second in full resolution mode, and while saving the full RAW image. Of course, this only works in electronic shutter mode, but unlike the Panasonic Micro Four Thirds cameras, the E-shutter has a fast enough readout to avoid the rolling shutter issues.
This makes the Nikon 1 cameras well suited for sports, for example, where you may want to take a 20 frame burst during a crucial moment, and then later pick the one you want to publish.
- The Nikkor CX 70-300mm f/4.5-5.6 (my review) long tele zoom lens. With an impressive 810mm equivalent focal length, this is the smallest birder-friendly lens available currently.
Combined with the very good PDAF AF-C performance, and the high frame rates possible, this lens makes the Nikon 1 system to a dream come true for anyone interested in photographing birds and wildlife, while wanting to keep the bulk of their gear down. The lens is also useful for spectator sports.
Fujifilm have invested a lot in their mirrorless camera lineup, and they appear to be committed for the long run. They have a very clear niche: Enthusiasts who like the classic lineup of lenses, and retro styled cameras. The cameras and lenses are of a high quality. And even if they look old fashioned, they do employ recent innovations. The Fujifilm system is for traditionalists who are not heavily into video.
Canon also have their mirrorless system. But so far, they only have a small handful of lenses available, and one first generation camera. The camera has very poor autofocus performance, and the ergonomy is sub optimal.
Finally, the rather odd Pentax Q cameras use the tiny 1/1.7'' sensor size, but the first generation used the even smaller 1/2.3'' sensor.