Is the full-frame DSLR dead and the DSLR a dying breed?

Because of the distance from the lens to the focus plane, SLR lens use a "retrofocus design." It works fine for longer lenses - in fact it is probably a better design for longer lenses. However, it can impact the image quality in shorter lenses. At 35 mm (135 format) is the point were retrofocus design can run into issues. That's why Leica lenses are the top of the line in the shorter focal lengths.

This is a good source for the difference - although it is geared to a range finder. In reality that is all a mirrorless camera is the same concept.

http://www.photozone.de/slr-vs-rangefinder

This discusses the issues with short lenses in an SLR

http://en.wikipedia.org/wiki/Wide-angle_lens

On the other hand designing a 135 format Leica M was a difficult task and required offset micro-lenses and probably resulted in an expensive sensor. It is unclear if an inexpensive mirrorless camera the size of a Leica can be produced because of the sensor design issues. If this turns out to be an issues, then you will have the crop sensor vs. the 135 format sensor. The reason medium format cameras were so popular during the film days is larger film formats produced better images. The same is true for digital. The FF sensor will produce a better image than the crop sensor.

I don't see the SLR disappearing any time soon. I do see more mirrorless cameras coming to market, however. At the end of the day the crop sensor camera is caught between to sides. The cell phone sensors are becoming better. The real growth will be in the cell phone cameras. As they get better, then that is going to most likely eat away at the compact cameras and eventually at the ASP sensor cameras.

It will all flush out, but it will take awhile.

--
Truman
http://www.pbase.com/tprevatt