Myth 1: It Doesn't Offer Enough of a Size or Weight Difference
I've spoken with countless photographers who often leave their DSLR home to avoid carrying extra weight. Some even purchase expensive telephoto zoom lenses only to complain they're too much of a hassle to bring along. If you do the math, DSLRs are about twice as heavy as mirrorless cameras and approximately 40% bulkier. When you're traveling to distant places or hiking deep into the woods, every ounce matters. I've been on small airplanes with a strict 25 pound luggage limit. Much to my surprise, that included personal items! Advances in technology can allow us to go places that were previously inaccessible. No longer does a photographer need to leave important things behind. That's one of the reasons carbon fiber tripods have become the preferred choice for many. Since they are much lighter than aluminum models, photographers can go further. Couple this with a lighter camera system, and it's possible to reach remote locations faster, giving you the competitive edge.
Myth 2: If I Want Mirrorless, I Can Use a Smart Phone
A mirrorless body has many of the conveniences of a smart phone (wifi, touch screen, small size), yet it also offers unparalleled creative control over the camera's settings. With it, one can shoot in RAW or JPEG, work with a full range of apertures, shutter speeds, and ISO. To be clear, we're not talking about the limited range on most point and shoot models. Depending on the lens, the depth of field can be as wide as f1.4 and as small as f22. Shutter speeds can be a lightning fast 1/4000 or a very slow 60 second, or bulb exposure. You can set custom white balance, access the histogram, swivel the screen, adjust the flash output, attach a circular polarizer or use a graduated ND filter. It can be attached to a sturdy tripod, and you can switch lenses, choose different metering modes, and select from a variety of autofocus or manual focus options. Don't get me wrong, it's possible to take wonderful photos with a phone. Yet, for those who want more creative control, there is no comparison.
Myth 3: EVF is Inferior to OVF
The quality of EVF in today's mirrorless cameras will surprise you. It's similar to using live view, but in the viewfinder where the display is not affected by harsh sunlight. Benefits such as data overlays, depth of field preview, and a live histogram actually make it more useful than the OVF. With in-viewfinder image magnification and focus peaking, manual focus has never been easier or more accurate. Furthermore, you can even see in different modes such as black and white or infrared.
Myth 4: It Can't Possibly Work Well in Low Light
If you look at some of the most important photos in the history of the world, they have a bit of film grain. Today however, many photographers would rather risk a blurry photo at 1/30 and ISO 800, than a sharp but noisy photo at 1/125 and ISO 3200. Magazines and camera companies have perpetuated this fear by constantly pushing the next model with "even lower ISO noise". The truth is, my first DSLR maxed out at ISO 1600. Today, I can set my mirrorless camera to ISO 12,800. That is a three stop improvement, virtually allowing one to shoot in near darkness. I'll gladly accept this trade-off for a bit of noise that can easily be cleaned up in post production. As such, I've used my mirrorless camera to shoot a variety of low-light scenes without hesitation.
Myth 5: The Technology is Not There Yet
It wasn't long ago when photographers argued over the virtues of film vs digital. We all know how that turned out. Recent shifts in the industry appear to signal a similar outcome with the mirrorless debate. We've come a long way from the Espon RD1 in 2004. Smaller sensors are already able to achieve much of what full frame models can. The major camera manufacturers realize this and are planning accordingly. In September of 2014, Canon's Managing Director and Chief Executive, Masaya Maeda said "We are serious. We are really focused on mirrorless and we’re spending lots of time, and devoting a lot of manpower to scaling up mirrorless development right now." Of course other companies like Fuji, Sony, Olympus, Panasonic already have well-developed product lines for even the most demanding photographers. Will full frame DSLR's eventually become the new medium format? Only time will tell.