Paddling Since: 2003
Join Date: Oct 2003
I wrote a response to someone asking me about this recently. He said I ought to share this information with the world - so maybe this is a good place. I'm not really an expert, so take it with a grain of salt, but maybe this is helpful. It seems like there must be 100 other better summaries out there if you could just find them, but here's a copy/paste of my response.
For someone like me, camera shopping is hell, as the number of options is overwhelming. I guess if youíre asking me about my camera that probably means sheís looking for an interchangeable lens system? Thatís probably the first decision to be made. If youíre just looking for something that has more features and sharper pictures, there are some options involving a fixed lens system with a better quality lens and a larger sensor (Sony RX100, Canon G1 X, ....). These are usually more compact, cheaper and mechanically a bit simpler.
It does seem like the most popular choice when trying to upgrade to a more sophisticated camera is the interchangeable systems though. However, if you just plan on only getting and using a kit lens, Iím not sure if that actually makes sense. Traditionally, Canon and Nikon dominate this domain. Something like the Canon T4i would usually be the go-to entry level DSLR camera when entering in this domain. If you pay more you tend to get some advanced features: faster and more accurate focusing systems, maybe a better sensor, a faster Ďshots per secondí rate, more adjunct connectivity options, and other bells and whistles.
DSLRs have a little mirror that flips when you hit the shutter (hence the SLR). In its normal position, light comes into the lens and goes to the optical viewfinder so you see (more or less) exactly what the lens sees. When you hit the shutter, the mirror flips down for an instant and redirects the light from the lens onto the sensor and records the image. Maybe you already know this.
The newer class of cameras is the mirrorless interchangeable lens systems. Thatís what I have. Mine is a Sony NEX-7, but there are various models in the NEX line (specs are easy to find online). Most manufacturers now have some sort of mirrorless system out. I think ultimately this will be the system of the future but there will be a long transition time as the systems mature. Currently, the majority of them use the micro four thirds standard. Sony (and I think Canon too?) took a slightly different approach and stuck with their own proprietary system where they use their own sensor and mount and hence arenít compatible with the array of micro four thirds lens offerings. The advantage of the proprietary Sony system is that theyíve stuck a larger sensor (roughly equivalent to the standard DSLRs) into the camera, whereas the micro four thirds has a smaller sensor and a very high crop factor on the lenses (2x vs. 1.5x). I think Canon did roughly the same, PLUS itís compatible with the traditional Canon mounts.
These cameras, by definition donít have optical viewfinders. Some rely entirely on an LCD screen (like a normal compact camera) and some have the LCD screen + an electronic viewfinder (which is handy when working in bright light and some like the way you can hold the camera to your face to frame the shot vs. holding it out in front of you).
So what are the advantages and disadvantages? Well, because the mirrorless systems donít have a mirror, they have fewer parts and can use a shorter flange distance and the bodies (and to some extent the lenses) can be made much smaller and lighter than DSLRs. This was one of the main selling points to me. For instance, I can fit my camera into the smaller sized Pelican case which goes much more easily into my kayak. For pretty much all of my applications though, smaller and lighter is better.
If youíre interested in video, another advantage is that they allow continuous autofocus when taking video. DSLR cameras actually require using the mirror to focus, and therefore you canít autofocus while filming (you can focus, start filming, stop filming, refocus, etc.) or focus manually any time (if your lens allows it). I guess some newer DSLRs do have a separate focusing system, but not sure if theyíre any good.
Another advantage of the mirrorless lens camera is itís not hampered by moving a mirror back and forth between shots and therefore they can achieve burst rates (i.e. 10 frames/sec or more in some cases) that were only available on pro level (think $3k+) DSLR cameras.
What is the advantage of a traditional DSLR? Well, as I mentioned, the mirror is utilized for focus, in what they call phase detection focusing. A normal compact camera without a mirror uses contrast detection focusing. In general, phase detection focusing is considered superior because it is faster in most conditions (esp. in low light situations). Some of the newer mirrorless systems are building phase detection focusing into the actual sensor, offsetting the advantage somewhat. I think itís safe to say that the best SLR will have much better focusing capabilities when put up against the best mirrorless. However, Iím less sure how low or midrange cameras of each variety stack up against each other. My old entry level DSLR didnít focus that well, so I donít feel like I lost anything there with my newer camera Ė maybe itís even a little better at focusing. I guess this area is the biggest deal to me. For most applications the focusing is fine, but in some cases, esp w/ very fast moving objects, it could be better. What I don't know is if, practically speaking, you'd get better focusing with an entry level DSLR or if you'd have to step up to one of the more expensive models.
The other main advantage of the DSLR is lens selection, especially when considering Nikon or Canon models. The mounts will be compatible with decades of old camera lenses and the options will be, well adequate and overwhelming. However, the fact that many of the lenses have been around so long means that in general you can find equivalent lenses cheaper for Nikon and Canon mounts than you can for other mounts (especially Sony, which seems to be a price ďpremiumĒ company sort of like Apple). Some will complain that Sony E-mount (the NEX mount system) doesnít have enough offers, but for my taste itís fine. I could see how many pro photographers would want more, but buying nice lenses can get outrageously expensive and I donít take the hobby that seriously.
One advantage that at least the Sony NEX line has, and I think the micro four thirds as well, is that they have a feature called focus peaking and some cool zooming operations that make it much easier to focus manually. This is esp. handy because without a strict flange distance requirement, itís easy to use OLD manual focusing lenses with a cheap adapter if youíre inclined to play around with that. It can also be useful though when your autofocus isnít cooperating.
Some people make a big deal out of optical vs. electronic viewfinders. The Sony has a fine electronic viewfinder and I donít think it matters much either way. I actually prefer the electronic viewfinder as it gives you an actual sensor rendering of the image, but some prefer the crispness of the optical viewfinder. A real disadvantage is that the electronic viewfinder drains the battery way more than the optical. Battery life is still good though. 5 days on the Selway and being careful not waste battery power, I made it mostly on one battery Ė think I put in my spare on the last day.
So anyway, yeah, choices are overwhelming. If you want an interchangeable lens system, Iíve been super happy with the Sony NEX-7. I paid lots of attention to what was available when I bought my camera but not much since. I think thereís a new NEX-6 (cheaper) thatís pretty nice and even offers some wifi and ďappĒ-type capabilities. Cheaper than that is the NEX-5(N?R?) which looks like a great deal for your money but you donít get the electronic viewfinder (matters to some people, not to others... I use mine frequently, but could get by without). Another feature you might not think much about but has been a big deal to me is the swiveling LCD screen. Mine can angle up and down. I use the angle up thing -all the time- to compose shots with the camera down low. Swiveling left or right would be even better but less important. I donít think youíd go too wrong with one of the standard Canon or Nikon DSLRs either, but youíll have a little bit larger form factor. People make a big deal about investing in a system because in theory youíll have lenses that will last you many, many years, but youíll upgrade/replace bodies more frequently.
dpreview.com is a good resource for reviews and general information.