In every field of technology, there are liminal moments when the new begins to outpace the old, and the bell begins to toll for the previous generation's greatest achievements. As I look past the Sony a9 across my collection of digital SLRs, I can hear a distinct ringing.

Mirrorless cameras have always had promise. The ability to preview a shot properly, including exposure, through an electronic viewfinder (EVF). The potential for smaller, lighter bodies with fewer clunky moving parts. The ability to shoot photos without swinging a mirror around and having to deal with that noise and vibration issue.

But there's been barriers for serious shooters. The EVFs weren't great to look at, and early on they were a touch laggy. The autofocus was slow, because it used contrast detect systems instead of the much quicker phase detect systems built into DSLRs. The shots looked good, but the experience of shooting with some of these cameras felt slow and clunky and … maybe a bit cheap.

Sony a9: that sensor, that wonderful sensor Loz Blain/New Atlas

As my couple of weeks with the Sony a9 come to an end, it feels to me like those barriers have been smashed through, and the DSLR's days are numbered. It's just that good. This is the future of the professional-level camera, and it kicks all kinds of ass.

We've already discussed the a9's ludicrous 20fps burst speed, compact size, 693-point phase detect autofocus system and frankly rude low-light ability in our first impressions piece from two weeks ago. Here are some more observations I've made in the interim, along with a heap of sample photos.

Sony a9 Sample image: ISO 4000, f/5.6, 1/125 sec Loz Blain/New Atlas

Entry-level accessibility

This is not the kind of persnickety beast that some high-end cameras can be. It needs no special treatment, and a rank amateur can leap into green mode and blow themselves away with image quality without ever needing to know what A mode stands for. The buttons are all in nice, intuitive places, with the exception of an exposure compensation wheel that's easily bumped out of whack, and I never found myself hunting for things for long.

I've (reluctantly) handed this camera to a number of people to play with, and they've all found it very friendly to operate, no matter how much I've instinctively cringed as they held AU$11,200 worth of camera out in front of them and shot stills looking at the rear screen.

That says to me that the a9 won't just be a high-end tool for imaging professionals. It'll also make a terrific buy for people with a bunch of money and not much interest in rolling the sleeves up to figure out how cameras work. And that's no bad thing for an industry that's losing sales to ever-improving smartphone cameras every year.

Sony a9 Sample image: ISO 320, f/2.8, 1/160 sec Loz Blain/New Atlas

Ridiculous continuous autofocus performance

The a9 can shoot 20 full-frame RAW photos per second, for more than 240 shots continuously, and using an electronic shutter it can do so without ever interrupting your view through the EVF.

That kind of performance is pretty mind-blowing in itself. What makes it even more impressive is that it's focusing three times faster than that, 60 times per second, using those aforementioned 693 points of phase-detect autofocus that cover almost the entire frame.

The end result is that you can open this thing up to f/2.8 at 200mm – giving a razor-thin focus plane – and fire away like a gatling gun at a rapidly moving subject, and the a9 nails almost every shot.

I tested this with predictable subjects; motorcycles coming down a racetrack straight right at me at full speed at the BMW G310R launch. I think I shot around 200 photos that day, and focus and exposure were perfect on just about every one. I promise you, I'm not that good. Here's one example for you, a bunch of others from the same sequence can be found in the gallery.

Sony a9 burst mode autofocus test. Subject approaching at over 100km/h. Burst mode set to maximum speed at 20fps. Photos cropped in to accentuate detail. Loz Blain/New Atlas

I also tested this with the most unpredictable subjects I could think of, by taking the a9 down to a local dog park, again at f/2.8 and 200mm, to challenge the autofocus as much as possible. That was a blast, let me tell you. Dogs are even more hilarious frozen in time than they are being their normal wacky selves. And while I did miss focus more often, I'd still put my hit rate at over 85 percent.

Sony a9 sample shot: ISO 100, f/2.8, 1/1600 sec Loz Blain/New Atlas

Face and eye detect modes also do a great job of making sense of what the sensor is seeing, and placing focus where we're most likely to want it.

That's not to say you don't get bad photos. Of course you do – it's just that they're bad because of composition, or the face somebody's making, or balance, or a hundred other reasons that are not autofocus performance. That is to say, if your photos are crappy on the a9, it's probably not the camera's fault, it's yours.

Video considerations

As good as autofocus is in stills shooting, it's not ready for prime time in video mode. The a9 shoots beautiful 4K video, sharply detailed and impressively stabilized, and it does have full-time autofocus. But it's slow, and if your subject moves around, it doesn't seem to be able to hold it.

It's strange; 20fps stills focus like lightning, 25fps video is much, much slower – even when you set the focus speed to fast.

Mind you, I'm not aware of any full frame camera that can nail video autofocus as yet –heck, the wonderful Panasonic GH5 can't even do a decent job with the much wider focal plane of a micro 4/3rds sensor. Perhaps video autofocus is still a few years away.

And to be fair, other video functions are reasonably well handled; the on-board microphone's not too bad, you get audio levels on your screen and zebra striping as an option. Focus peaking and auto-magnification are available to assist with manual focus.

Frame rate options are a little disappointing, though. That beautiful 4K image only goes as far as 30 frames per second, and slow motion in 1080p gives you 120 frames per second. It's a little odd, given the obscene speed at which this camera writes stills. Realistically, it's enough for the majority of jobs; and perhaps Sony needed to leave themselves somewhere to go with the inevitable a9 II.

Sony a9 sample shot: f/2.8, settings unknown Loz Blain/New Atlas

High ISO Performance

We've already touched on the a9's amazing low light performance, but doing an ISO noise test really pounded home for me the enormous gap between Sony's sensors and the disappointing efforts from Canon lately.

Sticking the camera on a tripod, I took a series of photos of a motorcycle helmet, then cropped in to a small portion of the image and made a PDF contact sheet out of them. You can download that ISO test contact sheet here, to zoom in and see the results at the pixel level. But at full size in a crunched-down Web format, let's see how we go:

Sony a9 ISO test: ISO 6400 Loz Blain/New Atlas

The uncropped image above was shot at ISO 6,400, where a Canon sensor is starting to fall apart. There's a little bit of noise in the a9 image if you look for it. Let's go to ISO 16,000:

Sony a9 ISO test: ISO 16000 Loz Blain/New Atlas

OK that actually somehow looks smoother and less noisy than the first one, probably due to our photo-butchering image compression engine. How about we jack it to ISO 64,000?

Sony a9 ISO test: ISO 64,000 Loz Blain/New Atlas

Still thoroughly usable in an online format. What if we max this thing out to a ludicrous ISO 204,800?

Sony a9 ISO test: ISO 204,800 Loz Blain/New Atlas

Aha! Finally, a photo that looks actively crappy at this resolution. Check that ISO test contact sheet to zoom right in where things get noisy a lot faster. I can't say enough about Sony's sensor technology, it really does set the standard for full frame imaging sensitivity.

Complaints

Beyond a few video niggles, this is a short list. I don't like the fact that it's not super quick to delete all the files on a card. Instead, Sony makes you delete images by date, which is a handy solution if you've already started shooting and you forgot to clear your card first. I'm sure there's a "format card" or "delete all" option somewhere, but it didn't present itself to me immediately and I don't see why it can't be right there in the "delete one/delete multi/delete all from this date" menu.

The flip-out screen doesn't fold out sideways, it stays in line with the body. That works OK in most situations, but not with a handheld stabilizing gimbal like the Moza Air, which are becoming more and more common in small-scale video production.

On many mirrorless cameras I'd complain about the battery life – after all, it's constantly running the sensor and either the rear screen or the EVF as well as everything else it has to do. But the battery life on the a9 is actually very impressive, pounding out about 480 shots, or more than 100 minutes of continuous video recording, on a full battery.

Sony a9 Sample image: ISO 100, f/2.8, 1/1600 sec Loz Blain/New Atlas

Conclusions

In all, this remains the best camera I've ever laid my hands on. The a9's bombastic burst speed is a thrilling diversion that never fails to impress, but let's not let bells and whistles distract us from how well this thing does the basics.

Image quality is wonderful. Dynamic range is superb. Color is terrific. Low light performance is extraordinary – not next-level like Sony's A7SII delivers, but outstanding compared to anything in the Canon range. Sensor noise is well controlled up to ISO 6400 or so, and under the right circumstances, images are usable up to ISO 60,000. Which is utterly ludicrous.

Autofocus is damn near unbelievable in stills shooting, and that furious burst rate is so fast you're almost shooting video, with every frame a RAW photo. The body is small and light enough to hang off your shoulder all day, at least until it's paired with a beastly piece of glass like the FE 70-200mm f/2.8 GM OSS lens Sony sent out with it. And it's also fairly good at video, even if it's not a world beater in that regard.

Sony a9: large rear screen is good, the EVF is even better Loz Blain/New Atlas

At AU$6,999 (US$4,499.99) for the body alone, and an extra AU$4,199 (US$2,599.99) if you want this amazing lens, the Sony a9 is going to be well out of reach for most people. And that's OK, it's a pro-grade imaging tool and a lot of those who buy it will be expecting to make their money back.

But to me, this camera is significant in that it takes on the DSLRs at their own game, and equals or beats them at every turn. Mirrorless is no longer a compromise, it's a pure advantage. I can't see myself ever putting money down on a DSLR again. Bravo, Sony, you have built a magnificent machine and pushed the state of the art forward.

Product page: Sony a9