SLR vs Mirrorless Cameras?
Recently I was drug into this issue by a friend of mine. After hours of discussion, and after reading countless articles on the issue further to that conversation...I am now quite certain that anyone who spends a great deal of time talking about this, on either side of this "debate", is missing the point.
I think the term SLR (Single Lens Reflex) itself is no longer significant. At one time, it was the defining feature of pro cameras. You saw through the viewfinder what the film saw...other camera architectures did not provide that. With Digital, this is no longer a major issue. Rather than an essential feature for a serious photographer, the difference between optical or electronic viewfinder is mostly a personal preference issue. I feel rather certain that most SLR photographers are more concerned with form factor and build quality than the actual viewfinder.
"Mirrorless" is also just describing the viewfinder system. No mirror, it uses an electronic viewfinder or back panel LCD to show you what the sensor "sees".
Electronic viewfinders may be limited in resolution (compared to optical) but they offer additional features such as highlight alerts and other live view options, that said, some may prefer the feel of their optical viewfinder, as well as the decreased impact on the battery. Again, I see these as personal preference issues, not defining characteristics.
(Yes, I know that removing the mirror has some other advantages, by the lens being able to be closer to the sensor allowing a smaller and lighter weight body - but even that is an issue of personal preference.)
Fanboys attribute all sorts of other attributes to both "SLR"
and "Mirrorless". For instance, all of Olympus' achievements are attributed to mirrorless. While I agree that the accomplishments of Micro 4/3 systems are enabled by mirrorless design, I do not think it is fair to attribute these things as merely traits of mirrorless. The fact that an Olympus m4/3 camera has great optics or image quality is a property of m4/3 and Olympus...not just the fact that it is mirrorless. Is the overall relevant issue the sensor or the viewfinder? I would argue it is the sensor. The sensor defines the image quality, in combination with the lenses for that sensor...not the fact that it is mirrorless.
Most common people think "SLR" actually refers to the style of camera. Most people who do not know Olympus would think an OMD is a small SLR. I myself would argue that the OMD bears more resemblance to an SLR than to the back-panel LCD mirrorless cameras. Why? Because of design and the fact that you shoot with it in a very similar way to how you shoot with an SLR.
I think what is more defining now is "Body style" and "sensor type" than the type of viewfinder. We are stuck in old terminology that is no longer defining the key relevant features.
Take this scenario that I recently presented to the mirrorless advocate friend of mine... Nikon decides tomorrow to licence the viewfinder software from the OMD, and releses the D800E - the exact same D800 body, but with the mirror ripped out and an electronic viewfinder instead of the optical one. Technically that SLR is now a mirrorless. But to anyone using them, they are almost identical. The optical viewfinder may be preferred by the old school purists, while I myself would seriously consider the Electronic viewfinder for the added features.
I contend that the OMD and A7R both bear more resemblance to an SLR than to back panel mirrorless cameras, because of the way the photographer will use them. At the very least they are SLR-style mirrorless.
I will not give up the "SLR-STYLE" of body for the foreseeable future, but am I emotionally attached to my optical viewfinder? Not at all. I am, and I imagine most photographers would be, open to electronic viewfinders - if they can offer adequate resolution.
Back panel mirrorless, on the other hand, does not interest me, except to replace a point and shoot. Again, the defining factor is not SLR/Mirrorless viewfinder, but the form factor. I like to shoot with a camera to my body, a stable platform, looking through a shaded viewfinder, not holding out a camera from my body trying to see the back panel LCD.
On the other hand, SLR-style mirrorless (like A7R or OMD) is very interesting...and I would like to see a version of the 5DM3 or D800 with an electronic viewfinder. Baby steps for Canon/Nikon as well as for all the old-timers who are resistant to change.
I see this, not as a revolution in camera technology, but as a natural evolution in it. Maybe in the future a super-resolution Google Glass will be paired with a digital camera so the glasses show you what the camera will take...and you will not need a viewfinder or back panel LCD at all.