If you’re a Macintosh user, you’re probably aware that changing processors is a big thing for software programmers. In the Mac world we’ve gone from Motorola 68000 to PowerPC to Intel processors, and each change has made for a lot of programming work.
What you probably don’t realize is that your DSLR has CPUs in it. You don’t see the mad rush to change software when CPUs are switched because it’s all done behind the scenes. Your camera controls and menus look the same because Nikon engineers have in the background been madly coding for the new processor.
We’re in the midst of one of those changes at the moment. Nikon used Fujitsu FR CPUs in their DSLRs previously, but recently started moving to ARM CPUs. This change actually takes place inside the EXPEED chip, where that CPU is housed. Basically, EXPEED 3A and 4 are ARM, EXPEED 1 to 3 are FR.
Some of my engineering friends hypothesize that the change from FR to ARM is partly due to perceived future needs to creature a full embedded platform for future cameras. Android runs on ARM, but I don’t think it runs on FR, for example. That’s not to say that I think that Nikon is moving towards Android, but I suspect that the open code base upon which Nikon can build is bigger on ARM. Or perhaps it’s just that it’s easier to find ARM-knowledgable engineers these days due to all those smartphones and tablets running on that platform.
In looking at the ARM versus FR cameras, it also strikes me that Nikon may be getting some performance gains, too. In particular, note that the new version of Group AF is only available on the ARM-equipped cameras.