There is a very good article from lensrental's Roger Cicala on tearing down a Sony A7r http://www.lensrentals.com/blog/201...de-sonys-awesome-full-frame-mirrorless-camera The whole article is quite interesting but the last paragraph is worth quoting... 'This is rather amazing. The completely disassembled Sony A7R consists of about a dozen major pieces, held together with 29 screws of just three different sizes. A typical DSLR has around 120 screws of 11 different sizes. You might not care less about that, but do you know what I thought about? How much easier it will be to fix this camera when it breaks. How much simpler it must be to perform all the calibration that must be done during assembly. And how much simpler it must be to assemble the A7R in the first place. In other words, how much cheaper it must be to make this camera, than to make a DSLR.'