Just My Opinion, So Here It Goes:
Sony's mirrorless cameras are fine for some photographers, but even with its newest addition, the a7 version II, I still wouldn't consider it a contender for my attention. And here's why: lack of diverse excellent, native lenses.
I've read a ton about the a7 series cameras. Heck, who wouldn't be tempted, it's a 24 MP full-frame sensor on a small mirrorless camera body. Not only that, but Sony is the one who makes the sensors for our tried-and-true Nikon DSLRs, so this isn't their first foray into the world of full-frame sensor-making. So where does Sony go wrong?
Almost every professional photographer attempts to use prime lenses whenever possible. Primes are clear, sharp, and optically superior to zoom lenses. They also have the one weakness of being inflexible when it comes to zooming in or out. And that's fine most of the time. But it isn't fine all of the time. That's why most professionals have two trusty lenses in their arsenal for those times: 24-70 f/2.8 and 70-200 f/2.8. The f/2.8 is essential for shallow DOF and shooting in low-light. Well, Sony has decided not to offer these lenses in f/2.8, only at a maximum aperture of f/4. The 24-70, 70-200, 16-35, and the 28-135 all suffer from being stuck at f/4 wife open. For this photographer, that's not ideal. So in regards to native lens support, it's not looking good. So how about using other manufacturer's lenses?
Lens Adapters to Infinity:
The FE-Mount wasn't Sony's original mount for DSLRs or mirrorless cameras. Odds are it won't be their final attempt either, which in itself is frightening. No photographer want's to invest money into a system that isn't guaranteed to be around in the near future. Let's take a look at all of the mount adapters Sony offers (link to this fantastic post highlighting all of the mount adapters):
- Sony LA-EA3
- Sony LA-EA4
- Metabones Canon EF to Sony E-Mount Smart Adapter IV
- Techart Canon EF to Sony NEX AF Adapter III
- Viltrox EF-NEX II Auto Focus Canon EF Lens to Sony NEX and Full-frame A7/A7R Cameras
- Metabones Leica M Mount Lens to Sony E-Mount Adapters
- Voigtlander VM-E Close Focus M-Mount to Sony E-Mount Lens Adapter
- Metabones Nikon F to Sony E-Mount Adapter II
And this list actually continues, these are just the highlights. Some might think this is a great thing - the Sony a7 series cameras can essentially be system-agnostic. Yeah, but not really. Each of these lens adapters behaves a little differently than the other (some retain AF abilities, some don't, some don't communicate metadata, others do) - you'll have to dig through the menus to manually allow focus peaking (if it works with that particular adapter) - and this doesn't even touch the image quality issue. Personally, I think the images look fine from the adapters, but I've read many instances where people aren't completely satisfied with the IQ of the images the adapters produce. So not only is it not a seamless solution to getting great glass on your camera body, the biggest flaw is physical: you're taking this tiny, mirrorless body and using huge, DSLR lenses on it with an adapter. This isn't a step forward, it's a step to the side. Just click that link where the adapter post is located, view the picture the author took. It's the minuscule a7 coupled with what appears to be a 300mm lens? Is this a joke? Are we really proud of this solution? The whole point of the making the camera smaller is to make it more portable, ergonomic, and less intrusive. We're really going to pair it with a gigantic DSLR lens to do work?
It Feels Like an Unsupported Platform:
The lens adapter solution isn't for me. It might be for some people, but it certainly isn't one that I can stand by. Successful camera systems are built on great camera bodies coupled with great first-party optics. When the first party (the camera manufacturer) doesn't care enough to make great lenses for its own camera, and instead relies on competitors, what does that really say about the platform? For this photographer, it says 'This camera system is not for me.'