The basics

To understand how mirrorless cameras gained on DSLRs so quickly, let's go back to basics. DSLRs have a reflex mirror that lets you look directly through the lens at your subject with no electronics in between. When you take a shot, the mirror jumps out of the way to expose the sensor. All of that adds bulk and, for most models, means you can't see the decisive moment when you take a photo.

At the same time, the mirror allows DSLR-makers to put autofocus phase-detect sensors directly into the light path via a secondary mirror. Those measure the distance to your subject before you even take the picture, making autofocus nearly instantaneous. You lose that advantage, however, when you shoot videos or photos in live-view mode with the mirror up.

Mirrorless and compact cameras rely on electronic viewfinders (EVFs) or, in many cases, just a rear display. EVF quality has jumped dramatically over the past year especially, with most medium- and high-end cameras packing at least 2.4 million dot OLED models. Unlike an optical viewfinder, an EVF shows exactly what the final image will look like. Optical viewfinders have very few advantages now, other than lower (zero to be exact) power consumption.

Some mirrorless cameras, like models from Panasonic, use contrast-detect autofocus that must hunt for proper focus via a sort of trial-and-error method. However, the majority, including models from Sony, Nikon and Canon, have hybrid contrast-and-phase-detect systems. The phase-detect pixels are built right into the sensor, so in theory, they can work just as fast as the systems on DSLRs. The problem is that they reduce the sensor area and can introduce horizontal banding into images. This isn't noticeable unless you're really looking for it, however.

In general, high-end DSLRs like Nikon's D850 still have faster autofocus systems than mirrorless cameras. However, models like Sony's A9 are closing the gap, and have more sophisticated eye- and face-tracking software. In addition, mirrorless cameras have superior video autofocus, with Canon's Dual Pixel phase detection a particularly strong performer.

DSLRs and mirrorless cameras let you change lenses, but you're stuck with what's built into a compact camera. While that's great for portability, a single lens means you're going to sacrifice something. Fujifilm's X100F, for instance, has a fast but fixed 35mm-equivalent f/2.0 lens and no zoom. Sony's RX100 V has a 24-70mm zoom, but it's slower at the telephoto end (f/2.8) and less sharp than a prime lens. Because of their size, compact cameras are ideal for street and tourism photography.

DSLR vs. mirrorless vs. compact

So should you get a DSLR, mirrorless or high-end compact camera? And do you need a one-inch, Micro Four Thirds, APS-C or full-frame sensor? How many megapixels? What about the low-light sensitivity?

Let's break these things down with some nice charts. Bear in mind that the points apply in most but not all cases. For instance, recent DSLRs and mirrorless cameras have improved live-view autofocus, vastly closing the AF performance gap.

DSLR Mirrorless Compact Best battery life Less battery life Least battery life Purity/clarity of optical viewfinder, but you can't see the final result Electronic viewfinder or rear display only, less clarity but what you see is what you get Electronic viewfinder or rear display only, less clarity but what you see is what you get Fastest, most accurate autofocus for photos, good for videos Fastest, most accurate autofocus for videos, good for photos Worst autofocus Most lens options for Nikon and Canon, allows maximum creativity and choice Good lens options, lack of a mirror means smaller lenses and slightly better optics than a DSLR Only one lens means less creative control but lightest, least bulky option Heaviest and bulkiest, good for professionals but bad for tourists who want to pack light Much lighter than a DSLR but also less stable for video and when shooting with large lenses Extremely light, often pocket-size

Sizing up sensors

Larger sensors are ideal for professional photographers because they offer more control over the image. However, there's also more that can go wrong if you make a mistake.

If you wanted a full-frame mirrorless camera most of last year, you were stuck with one choice (not counting Leica, which is out of most folks' budgets). That would be Sony. Over the last year, however, Nikon, Canon and Panasonic have all unveiled full-frame mirrorless cameras. The only holdouts are Fujifilm, which is fending for itself just fine in APS-C, and Olympus, the last company to use Micro Four Thirds exclusively.

At a size equivalent to 35mm film (36 x 24mm), full-frame offers the best performance in terms of image quality, low-light capability and depth of field. It's also the most expensive and finicky. While blurred background "bokeh" can look beautiful at f/1.4, the depth of field is so razor thin that your subject's nose will be in focus, but not their eyes. This can also make video shooting difficult.

The next size category is APS-C (around 23.5 x 15.6mm for most models and 22.2 x 14.8mm for Canon), offered on Fujifilm's X-T3 and X-T30, Sony's A6400, Canon's M-series mirrorless models and several compacts, among others. It's cheaper than full frame, both for the camera body and lenses, but still brings most of the advantages. You get still get dreamy bokeh, high ISOs for low-light shooting and relatively high resolution. With a sensor size equivalent to 35mm movie film, it's ideal for shooting video, and focus is less demanding than with full-frame cameras.

Micro Four Thirds (17.3 x 13mm), a format and mount shared by Panasonic and Olympus for their mirrorless cameras, is the next step down in sensor size. It offers less bokeh and light-gathering capability than APS-C and full frame, but it allows for smaller and lighter cameras and lenses. For video, you still get a reasonably tight depth of field with good prime lenses, and focus is easier to control.

The other common sensor size is Type 1 (1 inch). That's used mostly by compact models like Sony's RX100 VI and Panasonic's FZ-1000 II superzoom. The size permits a smaller camera body and lens but still offers much better image quality than a smartphone. Most high-end compacts, unlike many DSLRs and mirrorless models, offer 4K video.

It's worth mentioning that Sony makes the sensors for nearly all other camera manufacturers nowadays, with the exception of Canon and, in some cases, Nikon. Oddly, Sony's latest APS-C–equipped A6400 packs an older sensor, while Fujifilm's latest X-T3 and X-T30 have all-new, higher-resolution X-Trans sensors, presumably made by Sony.

Full-frame APS-C Micro Four Thirds Type 1 Largest consumer size (36 x 24mm) and highest resolution, up to 50 megapixels Second-largest common size (22.2 x 14.8mm Canon and 23.5 x 15.6mm others), resolution up to 24 megapixels 17.30 x 13mm sensor size, resolution up to 20 megapixels 13.20 x 8.80mm sensor size, resolution up to 20 megapixels Largest pixels for dimly lit photos and video with less noise, usable up to ISO 104,200 Pixels still big enough for low-light photos but more noise than full frame Not the best for low light, with the exception of purpose-built models like Panasonic's GH5s Even the best models like Sony's RX100 V will be noisy above ISO 6400 Razor-thin depth of field for artistic bokeh The sweet spot for video but fewer artistic bokeh possibilities than full frame Decent but not spectacular bokeh You'll need to zoom in and use a low f/stop for blurred backgrounds Narrow depth of field creates problems with focus and bright sunlight Easier to control focus and shoot in bright light Focus and light more easily controlled Relatively easy to nail focus, even wide open

*The above chart doesn't include medium format (which is larger than full frame) or APS-H (which is larger than APS-C, but smaller than full frame) because they are not common in consumer cameras.

Video

If you're buying a mirrorless or DSLR camera because of video and decent photos are just a bonus, then you'll have different needs. For vlogging, you probably want a selfie-type flip-out rear screen -- an item that's found on models like Canon's EOS R and the Panasonic GH5. Sony's latest A6400 does have a pop-up display, but as I discussed in my review, a hot-shoe-mounted external microphone will block it.

Here are a few other things you need to ponder. Does your camera line-skip for video recording or read out the whole sensor? Sony's A7 III, for instance, reads the entire sensor to produce crisp, artifact-free video. However, the more expensive A7R III can only do that in cropped APS-C mode due to the higher resolution. It can handle full-frame 4K, but does line-skipping, which produces so-called moire (rainbow colors) and aliasing (jagged diagonal lines).

The same applies to Nikon's Z6 (full-frame readout) and Z7 (cropped) and the Panasonic S1 (full-frame readout) and S1R (cropped). Sony's A6400, the Fujifilm X-T3/X-T30 and Pansonic's GH5 all scan the entire sensor and super sample, giving you crisp video with no nasty artifacts.

Is rolling shutter, or the "jello" effect that can skew video, well controlled? Almost all digital cameras have it, but it varies a lot by model and resolution shot. It's pretty brutal on Sony's A7 III at 4K, for instance, but much better on Fujifilm's X-T3 and the Panasonic GH5.

Other things to consider: How's the form factor for video (smaller isn't necessarily better)? How long can you shoot before the camera heats up or stops? Does it support 10-bit HDR video? Is there a microphone and/or a headphone jack? (If you do a lot of interviews, it's preferable to have both.) How's the video autofocus? With its fast, accurate Dual Pixel AF, Canon models like the EOS R are the gold standard for vloggers and one-man-band shooters, but Sony's latest models are catching up.

Our top picks: Mirrorless

Sony Alpha a7 III BUY If money isn't an issue and you're looking to get one of the best full-frame mirrorless cameras on the market, then look no further than Sony's A7 III. This top-of-the-line shooter has features including a 24.2-megapixel CMOS sensor, 10-frames per second high-speed shooting and arguably the fastest autofocus system of any full-frame mirrorless camera. On top of that, the A7 III can shoot 4K video at 24 frames per second, and it uses the entire 24.2-megapixel (6K) sensor to make footage incredibly sharp. It costs around $2,000, body-only, but for being a great all-around camera for photographers and videographers alike, it's worth every penny.

Nikon Z6

The Z6 is Nikon's answer to Sony's stellar A7 III and beats it in some areas, especially video. It delivers crisp, full-frame 4K, but unlike its rival, outputs 10-bit, 4:2:2 video for maximum dynamic range.

It features 5-axis in-body stabilization, has excellent low-light capability and delivers sharp, color-accurate images. Nikon has five lenses, including three zooms and two primes, and you can adapt F-mount DSLR lenses with a $250 adapter. The single XQD card slot is a mark against it, however, and the autofocus is slow in continuous-tracking mode.

Panasonic Lumix DC-GH5

The Panasonic DC-GH5 is widely used by professional videographers, and for good reason. It delivers ultrasharp video and gives producers lots of options in post with support for both internal and external 10-bit 4K 60fps video.

At the same time, you can shoot sharp, color-accurate 20.3-megapixel photos and save them on dual UHS-II card slots. Where the GH5 falls down is with its contrast-detect AF, which tends to be slow and "hunt" for focus when you shoot video.

Fujifilm X-T3

Fujifilm's X-T3 is, quite simply, the best X-Series camera the company makes. The company has really stepped up its video game in recent years, and the X-T3 pushes the envelope with 4K60 capture and pro-grade features like 10-bit video with log and separate headphone and mic sockets.

Of course, the X-T3 is also a more-than-capable camera for stills, with Fujifilm's trademark traditional dials, fast and very configurable autofocus, rapid shooting, and an excellent selection of lenses to choose from.

Canon EOS R

Canon's EOS R takes the 30MP sensor from the flagship 5D Mark IV and packs it into a lightweight mirrorless body with a fully adjustable screen. The EOS R takes great images and puts Canon's innovative dual-pixel autofocus to good use, complete with face and eye-detection, though it can struggle a little to continuously track focus.

If you're focused on video, however, you may want to look elsewhere: The EOS R lacks in-body stabilization, and while it can record 4k video, it does so with a pretty extreme 1.8 crop factor, making wide-angle shots hard to capture.

Our top picks: Affordable mirrorless

Fujifilm X-T20

Often, the best affordable camera isn't a purpose-built "budget" model but an older shooter. Fujifilm's X-T20 is a generation behind the latest and greatest but, at its current price, more than holds its own. It includes the company's superb 24-megapixel "X-Trans III" sensor, solid a 3-inch high-res tilting display, and an OLED viewfinder.

You also get access to the same high-quality lenses as any X-Series camera. Sure, you lose some autofocus performance and its video options aren't as robust as the X-T30 that replaces it, but if you're on a tight budget, the hundreds of dollars you'll save make the tradeoffs worth it.

Olympus OM-D E-M10 Mark III

Olympus has designed the E-M10 series for entry-level photographers who want better image quality and, more important, versatility than a smartphone. The latest model, the Mark III, packs a 16.1-megapixel sensor, five-axis image stabilization and an OLED viewfinder into a petite camera body.

The Mark III also has a tilting touchscreen and two customizable buttons. At $649, it's the perfect gateway into Micro Four Thirds (M4T) photography and, depending on your budget, could leave you some extra cash for lenses and accessories.

Panasonic Lumix DMC-GX85

Here's why a 3-year-old camera is on this list: Panasonic's Micro Four Thirds GX85 mirrorless camera is really cheap and still really good.

For just $500, you get 4K video, 8 fps shooting speeds, 5-axis in-body stabilization and, typical these days, two free lenses. All of that fits in a compact, stylish body, making it ideal as a street photography or walking around camera -- especially when paired with a lens like Panasonic's tiny Lumix G 20mm f/1.7.

Sony Alpha a6300

With the newer and more powerful A6400 and A6500 out, it's easy to forget that Sony's Alpha A6300 is still around. But even if it was launched in early 2016, the A6300 continues to be one of the best midtier mirrorless cameras. thanks to its 24.2-megapixel APS-C sensor, 4K video and 11-frames-per-second continuous shooting.

The best part is you can now find it on sale for about $700, which is much less than the $1,000 it retailed at when it launched.

Sony Alpha a7

This is the only full-frame camera on our affordable list. There's no doubt Sony changed the mirrorless-camera game when it introduced its A7 in 2013. Six years later, while it isn't the most powerful full-frame mirrorless anymore, the A7 is still a great choice for people looking to get into photography.

A big reason for this, aside from its 24.3-megapixel CMOS sensor and 5-frames-per second shooting, is that the A7 is compatible all of Sony's native full-frame E-mount lenses, of which there are more than 48 to choose from. Probably the best feature of the A7, though, is that it's almost half the price of the A7 II that replaced it.

Our top picks: Compacts

Canon PowerShot G7 X Mark II

Looking for a trusty point-and-shoot with a versatile lens and don't want to spend $1,000? The Canon PowerShot G7 X Mark II -- with a 20MP sensor and strong low-light performance -- might be the camera for you.

The G7 X Mark II's lens is 24-100mm equivalent, and it comes with a tilting screen, manual control ring that can be used to adjust aperture, focus or zoom (among others), and even a tilting pop-up flash. Its 12-bit raw files give a lot of flexibility in editing, and while its battery life falls a little short of the competition, if you need a travel or social camera, the G7 X Mark II has a lot to offer.

Sony Cyber-shot DSC-RX100 VI

Sony's RX100 line offers tremendous image quality in a stupidly small form factor. The latest model, the mark VI, is arguably the best compact camera on the market. It has a 21-megapixel sensor that can shoot gorgeous stills and crispy video footage at both 4K and 1080p resolution.

The 24-200mm lens is versatile, and the auto-focus is ridiculously fast. We also love the pop-up viewfinder that helps you frame shots in any lighting condition. The downside, of course, is the price-tag: At $1,200, it's a huge investment for most people.

Fujifilm X100F

To the untrained eye, it might seem like Fujifilm has been making the same camera for 8 years. Rest assured, it hasn't. The X100F is the fourth in a line of fantastic point-and-shoot cameras. It borrows the X-Trans sensor from the company's last flagship, pairs it with a sharp 23mm (35mm equivalent) f/2 lens, a ton of traditional dials and a hybrid viewfinder that blends the best of rangefinder and conventional systems.

Yes, 1080p video might be outdated in 2019, but in every other way, the X100F is a photographer's dream. Well, as long as your dream is to spend DSLR money on a point-and-shoot.

Fujifilm XF10

Despite Fujifilm's spec sheet screaming about 4K video, the XF10 is for one thing: shooting photos. It has an APS-C sensor, superb JPEG processing, great high-ISO performance, its lens is sharp and its controls are simple. It's light, it's, let's be honest, really quite pretty, and it charges over USB.

The XF10 doesn't quite stand up to the rest of the cameras on this list -- not least the confusingly closely named X100F -- but we love it all the same. It's a lot of fun to shoot with, and it's (comparatively) very cheap.

Panasonic Lumix DC-LX100 II

If you're looking at Sony's RX100 VI but want a larger sensor and cheaper price, the LX100 II might be your compact camera. It has a 17-megapixel Micro Four Thirds sensor, 24-75mm f/1.7-2.8 zoom (35mm equivalent) and 4K video.

Then there's the handsome body and some manual controls, which make it great for tourism and street photography. The main drawbacks compared to the RX100 VI are the fixed rear screen and inferior viewfinder.