So youve been trying to pick out a camera, not sure what to get, but you have heard of these hot new Sony and Fuji mirrorless cameras, eh? What makes these new Mirrorless cameras so popular? I thought DSLRs were better? All the pros use DSLRs right? Well, lets go over what it means for a camera to be a DSLR or a Mirrorless (Mirrorless Interchangable Lens Camera, or MILC).
First off, lets jump straight to this point: There is absolutely no difference in image quality between a MILC or a DSLR. None. Zilch. Nada. In fact, many MILCs have superior image quality to DSLRs (this is mainly attributed to the fact that everyone and their mom gets their sensor from Sony, and Sony saves the best for themselves). The only defining factor between a MILC and a DSLR is in the name
the Mirror. When a DSLR takes a photo, that mirror flips up out of the way, meaning that it has ZERO impact on the actual photo taken. All the same settings are there, all the same photos are possible, all of that is the same. The only things that change are the bits that happen before the photo is taken.
So what does change? First, foremost, and arguably most importantly, the viewfinder. A DSLR uses its mirror to reflect the light away from the sensor through a piece of glass that you look through you see the actual light passing through your lens. With a MILC, instead, it hits the sensor directly, then reprojects that image from a little screen on the viewfinder.
So what are the consequences? Well, with a DSLR, youre not looking at pixels. That can make the image clearer, and not prone to pixilation. In low light, *in general* (not always the case) a DSLR will fare better, as your eye will be able to adjust better than the camera. Thats not always the case, as the A7S cameras can fucking see in the dark because they are built from goddamn Predator technology.
Now, I can reasonably assume everyone has at least *used* a DSLR and has used a viewfinder, so its probably easier from here to describe an EVF (aka the MILC viewfinder) as a comparison. With an EVF, it is a *screen*, so it is done with, well, pixels. Imagine how your phone screen displays, but its coming through a viewfinder instead of just the rear of the camera. But, theres some major advantages that come with using an EVF First and foremost is exposure preview. What does that mean? Well, it means that you can see the effects of your exposure settings before you take the shot. With a DSLR, changing your shutter speed and ISO have zero effect on your viewfinder, so youre left to either use the Light Meter and your imagination, or take a test shot. An EVF shows you, more or less, the photo youll get at the correct brightness, so it really helps to show you what effect the settings you have are making. Personally, I really loved learning on MILC, as I could really know what effect the shutter speed was having, or the aperture, etc.
This next point is mainly an advantage if youre interested in vintage or manual lenses namely, MILCs kick fucking ass when it comes to these. Firstly, a MILC can use almost literally any lens designed for any DSLR or Rangefinder camera. Found a random Canon AE1 in a garage sale? You can use that lens. Grandpa left you a Leica? You can use that lens. Have a modern Canon DSLR? You can use that lens. You can use fukken anything. Its amazing. And not only that, but any manual focus lenses ARE BETTER on a MILC, because a MILC can use Focus Peaking to show you whats in focus! Seriously, its amazing.
But its not all sunshine and roses. Theres no clear, flat out winner between MILC and DSLR. While MILCs are a lot smaller body wise, lenses largely dont get any advantage out of that a 70-200mm 2.8 is, ultimately, going to be a 70-200mm 2.8 regardless of whether its made for a MILC or a DSLR. This is two fold some people say that the gigantor lenses are better balanced on a large, pro DSLR body (think of a giant cinderblock, with a camera in it), and prefer that; it feels better in the hands to match a large lens with a large body. But, conversely, a 50mm prime cant shrink down a pro DSLR body but a full frame Sony camera with a 50mm lens on it is freaking tiny in comparison. Personally, I lean towards feeling that while a Sony camera with a pro zoom can become large, a pro DSLR can *never* become small, but this is just personal opinion.
Another plus to DSLR is that they have larger room for batteries they put that size to work. They also only need to energize the sensor when taking a shot, which leads to further battery life. A DSLR will pretty handily have the advantage in battery life, and its not a small margin. On a MILC this can be *managed*, either by choosing when to have the camera on, and when to have it off, or by using the saved space to pack an extra battery, but ultimately if battery life is king, youll want to lean towards DSLRs.
Another plus for DSLRs is that they have an advantage in native glass. While MILCs can use fucking any lens they want more or less, they arent native old vintage lenses obviously dont have Auto focusing or other conveniences, and adapters for newer lenses are expensive and often not quite perfect. DSLRs have been around for a long time, and have built up a collection of lenses for anything and everything, and have even had the time to become cheaper in most cases. As MILCs continue to thrive and exist, this advantage will start to wane however, and for *most* cases theyll have a lens to suit your purposes its mainly in the super zoom category that youll be left wanting on MILC side.
Autofocus is a tricky subject MILCs are still very much in a rapid progression, so what was true two years ago isnt true today, and AF is VERY much a prime example of this. Youll REALLY need to view this on a case by case basis, as even just going from the A7II and the A7RII, theres a large difference in AF capability. Just know that, unless youre already used to pro DSLR levels of AF, you probably wont be disappointed with MILC AF on the latest bodies. Hell, I think the A9 actually matches those blow for blow.
TL;dr
DSLR pros: lotsa (native) lenses, more natural viewfinder, better battery, possibly better ergonomics when using large lenses
DSLR cons: Viewfinder doesnt show how your settings affect the image, a DSLR can never be small, manual focus is a pain at best and vintage lenses dont really work IMO
MILC pros: Near infinite vintage lens compatibility, viewfinder shows you your exposure, manual focus is piss easy
MILC cons: AF can suck on older (2~ years old) cameras, eats battery if youre not careful, native lenses are still a WIP