I've been shooting the Sony NEX series APS-C mirrorless cameras for about a year now, and the [NEX 7](http://refer.ly/r/ab07/show) has practically replaced my [Canon 5D Mark III](http://refer.ly/r/ab0v/show) as my default camera. Although I still use SLRs when I need to be practical and productive as a photographer (and, underwater), the NEX 7 is small enough to fit in just about every bag I carry around, which means that I'm more likely to have a NEX on me than I am a SLR[^1]. I have been enthusiastically recommending mirrorless cameras to my friends for the last year because of their performance to size ratio. A [Panasonic GF3](http://refer.ly/r/ac0b/show) with kit lens can be had for around $300 when there are sales, and an upgrade to a larger sensor can easily be had (for more money) by going Sony NEX (~$600). It takes $400 to buy a Canon S100—the current king of small-sensor point & shoots, and a GF3 will shoot circles around it (but won't fit in a pocket).
[^1]: I have and love my NEX 7, but think I would have been just as happy if I had just kept the 5N. But this is because I have more than one camera. I think the Sony NEX 5N is the perfect second or third camera, but if I were choosing a primary advanced camera, it would be the NEX 7. Does anyone want to trade their 5N for my 7 in exchange for the difference in price? :)
All of this has changed with the release of the [Sony DSC-RX100](http://refer.ly/r/acDt/show) point & shoot camera. The Sony DSC-RX100 is the single (non-light field) camera I've been most excited about in years. A lot of my friends want cameras that produce fantastic pictures, but other than flipping to aperture priority every once in awhile, they don't really want to think about the camera when taking pictures. The 1" sensor combined with a wide-open aperture of f/1.8 (at lowest focal length) means clean pictures and the ability to produce a shallow depth of field comparable with what mirrorless cameras can do with their standard kit lenses (the lenses most people buy when they go mirrorless). The RX100's sensor is smaller than the sensor in a M4/3 or NEX camera, but the lens' aperture is larger in relation, which makes up for the difference.
What's huge to me is that the RX100 will fit into my pocket without making my look like a pervert—and, it does this without sacrificing much image quality. The best camera is the camera you have with you, and the RX100 is the first digital camera that performs more-or-less at large-camera image quality while still fitting in your jeans pocket.
The single downside is the price. The RX100 [retails at $650](http://refer.ly/r/acDt/show), which is more than many M4/3 kits cost, and about the same price as a Sony NEX F3 kit. Most people won't be used to paying that much for a point & shoot camera, but I think it's absolutely worth it. I will likely have this camera with me at all times, even when I'm not carrying a bag, and that is worth a premium.
For more opinions about the Sony DSC-RX100, check out these reviews:
- David Pogue calls the RX100 "[the best pocket camera ever made](http://www.nytimes.com/2012/06/28/technology/personaltech/a-pocket-camera-even-pro-photographers-can-love-state-of-the-art.html?pagewanted=all)." When I talked to him about the camera in person, he said that he basically couldn't take a bad picture with it. - Luminous Landscape says, "[the new Sony RX100 is hands-down the most appealing pocket-sized digital camera yet](http://www.luminous-landscape.com/reviews/cameras/sony_rx100.shtml)." - EOSHD says, "[the RX100 is definitely a viable replacement for a DSLR with kit zoom](http://www.eoshd.com/content/8499/sony-rx100-review)." Read their review for notes about the camera's video performance.
My Sony RX100 arrives on Friday; once the box is open, I suspect that my Sony NEX 7 will start to collect dust.
Referral link: [check out the Sony DSC-RX100 on Amazon](http://refer.ly/r/acDt/show)
**A quick note for underwater photographers:**
I still believe that underwater photography requires the use of a SLR for productive, "normal" underwater photography. A second underwater mirrorless rig (w/tiny dome port) could be very useful for free-diving and strobe-less, wide-angle shooting. If you're swimming with a pod of dolphins, you will likely be more producive with a tiny housing than will with a large SLR housing. This 2-camera setup is what I would shoot with if I were still traveling 6 months a year for underwater photography. Lytro has forced me into a 6-week a year shooting schedule, so I'm (at the moment) content with a single SLR setup.
Regarding point & shoots underwater: I'm not convinced that any point & shoot on the market right now can work as well as an SLR, underwater (including the Sony RX100). Most of the productivity in underwater photography is afforded by good ergonomics. We shoot primarly manual exposure—and often, manual focus— which can be difficult to accomplish with point & shoot ergonomics, especially when you have 100 sharks around you or are swimming against a strong current. Note also that all of this might change quickly. Mirrorless cameras and point & shoots are getting better very quickly, while SLRs are on a flatter improvement curve. In a few years, we may find that electronic viewfinders are better than optical viewfinders, and that pro-level ergonomics are also available. When this happens, my opinion will likely change.