Sony a9 Vs. Nikon D850: No, I'm Not Switching

Last year Sony released the a9, the pinnacle of mirrorless camera technology. Since then I have not stopped hearing about this camera. I know I'm late, but I finally got my hands on one, and I was able to play with it for a couple of weeks. How does it compare to my Nikon D850? Let's find out. 

Mirrorless Versus DSLR

A DSLR or digital single-lens reflex camera has a mirror that reflects the scene from the lens up into an optical viewfinder. When you take a picture, the mirror flips up, blacking out the viewfinder while it exposes the image. Most point-and-shoot cameras don't have a mirror and may not have a viewfinder at all, but professional Sony mirrorless cameras have digital viewfinders that mimic what is on the screen on the back of the camera. You can choose to use the screen on the back of the camera or use the digital viewfinder if you are in bright lighting conditions. 

Many photographers prefer mirrorless cameras because the cameras can be physically smaller and they may actually prefer a digital viewfinder. We will talk about the pros and cons of mirrorless cameras as we go through each facet of the a9 camera.

Form Factor

The Sony a9 is significantly smaller than any other professional DSLR I've used. Some photographers (who have small hands) will love it while others, like myself, will find it uncomfortably small. Someone pointed out to me that Sony sells a hilarious product to fix this very issue. Maybe I could get used to this over time, but throughout my entire trip, I was constantly upset with how the a9 felt in my hand. 

Digital Viewfinder

The digital viewfinder in the a9 is good, but it's not quite as good as I was expecting. At this point I am accustomed to ultra-high resolution displays on my computers and on my cell phone. The a9's digital viewfinder is sharp but you can definitely still see pixels. If you're used to working with an optical viewfinder, this will take a little getting used to, but it's much better than digital viewfinders of the past, and most photographers these days seem to prefer digital viewfinders. 

Battery Life

I wasn't able to do any scientific tests with the a9's battery, but I only charged the battery once during my 10 days with the camera. Keep in mind I was only using the camera for a few minutes each day, but this still felt like a major improvement over older Sony cameras I've used. 


The autofocus on the a9 seemed very similar to my D850. It was fast and accurate but it wasn't magical. I still got the occasional blurry shot and in dark situations, I found the autofocus still hunting for contrast. Apparently, I missed one of the best features on the a9 which is "Eye AF" which can track a human eye and will maintain focus on the front eye of your subject. I'm sorry that I overlooked this feature but I did want to mention it since a9 owners seem to love it. 

Autofocus while recording video, even in 120 fps, was superb. For the first time ever I was able to rely on a camera to pull focus for me and it was liberating. Because I am shooting more videos than stills these days, this was probably the feature that I was most envious of especially since my Panasonic GH5 cannot autofocus at all in 120 fps. 

Image Quality

The Sony a9 was created with sports shooters in mind. For that reason, speed was given a priority over megapixels. The a9 has 24 megapixels, which to me is plenty of resolution, especially for something like sports or weddings. 

I wasn't able to do any side by side tests when it came to image quality, but all of my shots looked great. The files looked very similar to the photos taken with my Nikon cameras but seemed to be lacking that neon red Nikon images tend to have. 

Video Recording

The a9 is capable of shooting in 4K but in my tests the camera "punched in" and only used the center of the sensor to record because I was shooting in 30fps. Apparently the camera uses the entire sensor if you shoot in 24fps but crops at 30fps. The camera also shoots in 1080p and in that resolution it will not crop the sensor. It also shoots up to 120 fps at 1080p and the footage looks solid. 

The footage out of the a9 looks great but when you compare the video features side by side with the GH5, I still prefer the GH5. 


The a9 has 5-axis stabilization built into the sensor. I have to admit, I'm so spoiled by the magical stabilization of my Panasonic GH5 that I didn't really notice that the Sony stabilization was working at all. I'm sure it was working to some degree but it just can't compete with the 5-axis stabilization of the smaller sensor in the GH5. 

Silent Shooting

Perhaps the most incredible feature of the a9 is the silent shooting mode. For a camera to do this, it has to digitally turn the sensor on and off rather than using a physical shutter. The technical hurdle where most cameras fail has been with the "rolling shutter" issue. Most full-frame sensors have incredibly slow read rates that produce a rolling shutter in both stills and video since the sensor has to read from top to bottom, one pixel at a time. The a9 has the fastest sensor I have ever tested. I've read online that the digital shutter is equivalent to 1/160 of a second. This actually makes silent shooting a professional option now as it can create flawless looking images without any warping. 

High-Speed Shooting

The incredible speed of the a9 sensor and digital shutter allows the camera to shoot put to 20 frames per second, totally silently, without any blackout. Imagine if you could record video and silently pull 25-megapixel frames from that video without any loss in quality. That's basically what the a9 is capable of doing. 

I personally never shoot rapid fire like this so the feature isn't of much value to me, but if you shoot sports, animals, or any fast moving subjects, this camera may be the best option for you. 

Should You Switch to Sony?

The short answer: maybe. The Sony a9 is amazing, but it's not better in every way when you compare it to the best that Nikon and Canon have to offer. It's just different. 

There is one feature, however, that stands out to me that is significantly better: the silent shooting mode. If you shoot on a movie set and you're currently using a sound blimp to reduce noise, sell your gear and buy the a9 today. I'm not sure any camera on the market can compete with the a9 in this arena. 

But for everyone else, even sports shooters, the a9 is pretty equivalent to other cameras on the market. Maybe it's a little faster but the battery life is a little worse. Maybe it has no blackout shooting but it's uncomfortable to hold. You should test it out for yourself and decide which camera is right for you before buying this new camera. 

Just a few years ago I didn't think that Sony cameras were as good as top of the line DSLRs, but I did say that I thought they would be the future and the future is here. At this point, Sony has created technology that is equivalent if not better than top of the line DSLRs. Today, I'm still very happy with my Nikon D850 and my Panasonic GH5 but if Sony keeps improving, even I might be making the switch to Sony in the near future.

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Jonathan Brady's picture

Good read and seems fair/balanced. Can't believe you missed out on eye AF though. My A9 will track my kids eyes while they run at me with 90%+ in focus.

Simon Patterson's picture

The video comparison did consider autofocus (with the A9 getting a very good rap) although it didn't specifically mention all the autofocus modes that were used on each camera.

Going into that level of technical detail would probably be over the top for a "real world" comparison video like this one.

But you're right - I see in the article he says he didn't use the eye af. All accounts are that it is very good.

Jorge Cevallos's picture

Yout videos are the best, Lee!

Jon Tascon's picture

Seems like 2018 is the year of mirrorless because Nikon, Canon and Sony have plenty of announcements down the road. You may be completely switching to mirrorless eventually, whether you like it or not, depending on how hard the major brands push the mirrorless button. For my money, I am not switching either, because I have been shooting Sony since 2010 and A7RIII is where my money is at these days with A7RII as second body. Tried the A9 but doesn't work for me: too expensive, hated the top left selector (prefer to change those settings in the menus) and I want my full 42 Mp, please.

Bjarne Solvik's picture

To me face detection and eye autofokus are important, and it works well most of the time. Autofocus is good, but you need to set if camera should only fire when in focus, or balanced, or loose. If set to af-priority it will not fire less in focus. Default settings will give some blurry images.
( Priority Set in AF-C most likely AF-S also)
I don't understand why anyone would want to have it set balanced, and get blurry images. But the original A7 as well as M2 will fire off even if not in focus and do not have option to change it. You need the beep before you fire with those.

Mr Hogwallop's picture

If the form factor is the same as the A7 then it will feel a little awkward, that's the second reason I almost always use the battery grip. The Sony doodad might help, like the wooden handle helped the old Pentax 6x7.
But after shooting Sonys for 2 or 3 months I needed my Canon 5d part deux with a 24-105 Siggy for an event...that sucker weighed a ton...ok I exaggerate but it was heavier than the stealthier A7s (without grip, because I wanted to be stealthy) Once I got used to the EVF I loved it and was annoyed by the Canon OVF. LoL

Dan Donovan's picture

Having the focus points cover nearly the entire frame is a HUGE benefit for Sony. And the electronic viewfinder lets you see the exposure without needing to take a photo and then chimp. This is fantastic. And oh yeah, the histogram can be displayed in the viewfinder as you compose and shoot (not just afterwards when looking at a photo that has been shot). Finally, as a people photographer, the eye-af is a really, really big deal.

Jake Lindsay's picture

Pretty fair comments especially coming from DSLR world. They only things I would push back on are the real world application of 12-14fps vs 20 and silent shooting modes. For professional sports this is absolutely a game changer. For golf you are only allowed to start shooting after the player has completed their transition and is right at impact, and if you're timing isn't perfect you're kicked out and likely losing your job. And the difference between 20fps and 12-14 offered by canikon sports camera could easily be the difference between an incredible image that tells a story vs an ok run of the mill shot. I also think the silent mode would be invaluable for weddings/church events. Just my two cents.

Chad D's picture

I shot enough with the Olympus I want my FF to be mirrorless

but I think many need to quit the thought of switching to sony and think switching to mirrorless ?

if when Nikon and Canon comes out with their FF variants and if they are good how many will switch to the same brands they are on now I do think the DSLR days are numbered

if we go back in time to the 80s you had to shoot med format mocking to them 35mm c
then the 90s came and 35mm was cool and med format was on its way out
then 2k the digital and the same med format guys that finally switched to 35 were saying never to digital I reckon those are the same folks saying no to mirrorless as in it taking over :) not about switching to sony again about mirrorless taking over sony is way out front but fuji and oly are making great gear for many to

H T's picture

I found most of your assessment fair, but saying the auto focus in stills mode is comparable to other systems but not mentioning the eye auto focus or almost full sensor focus coverage doesn't tell the full story. Also, the crop in 4k video is mild (less than 20%) and only happens in 4k 30. No crop in 4k 24.

Josh Tatro's picture

I think it's fair to suggest that the combination of stills and video quality you get from the D850 and GH5 combined is enough to prevent you from switching, but it seems a little unfair to pit one Sony camera against two flagship cameras built to satisfy two different sets of users (videographers with the Panasonic, photographers with the Nikon). If that's the test, wouldn't it be more apt to compare an A7S and A7R III combo to your preferred dual camera set up? In the end, it's not really the "Sony A9 vs. Nikon D850" when you swap for the GH5 whenever video features are concerned - especially when the A9's usability in video (e.g. live view AF) is head and shoulders above the D850's.

Luke Adams's picture

Boom. Mic drop.

Lou Bragg's picture

He’s comparing apples to oranges. Two cameras with completely different characteristics, each one with its weaknesses and strengths. BTW, I prefer strawberries....

Samatcha Apaisuwan's picture

At my 52-year-old eyes, I really need to review my shots in those EVF, rear LCD is no use for detail checking

Deleted Account's picture

My eyes are a bit older than yours. I rarely review my shots in camera (Thanks years of shooting with film!) and couldn't see it very well even if I tried. ;-)

mad xam2's picture

Beside the test i thought they had stopped open door helicopter flights over manhattan, because
of the accident that happens some time ago, what´s the story here?

Lee Morris's picture

They upped safety but the company out of New Jersey still allows doors off.

Patrick Hall's picture

What does doors on or off have to do with a helicopter sinking into the river? It wasn't the doors off that caused the tragedy.

mad xam2's picture

Because doors off flights require a harness to be strapped in the helicopter and not just
a simple strap?? Because the fact that the normaly used type of harness could not easily
be cut off in a emergency situation by a person wo has not undergone a seal team training

Adrian Luca's picture

You should compare you D850 to Sony A7iiiR, that would be fair comparison. The A9 is in the D5 territory in my opinion.

Lee Morris's picture

I agree. I actually have a a7riii here I need to review.

Luke Adams's picture

Actually, I think it would be good to stick to comparing the Sony A9 to just one camera. This article is framed as the A9 vs the D850, but you switch to comparing the A9 to the GH5 wherever it’s more convenient to support your thesis (why you wouldn’t switch). I don’t personally care what camera brand people use (as long as it’s not Canon!), but the article seems to have a built-in bias for sure.

Lee Morris's picture

Well the D850 is also cheaper than the A9 so that's not really "fair" either. I see what you're saying though and if I had to shoot video with one of them, I would choose the A9 over the D850. But I still like shooting video with the GH5 over both of them.

Luke Adams's picture

Price is a consideration/factor in any “vs.” argument. But, It doesn’t make it an unfair comparison in and of itself.

David Crossley's picture

We throw in a 100-400 rigged A9 for video on multi day backcountry assigns now that Sony has the battery capacity improved. Lack of teles longer than 400mm keeps me from switching.

Quincy Fivelos's picture

Good review Lee. My D850 has solidly supplanted my D5 & D800. The D5 now mostly does video duty so it and Ronin-S (formerly Moza Air) are setup together. I've not had anything action wise that made me think I needed the D5 instead of the D850.

I'm in no rush to move to mirrorless. For what I'm doing my D850 does as well or better than any of the Sony's. The Z6 may move me in that direction depending on specs but I'll likely wait until at least 2nd generation and possibly 3rd unless there's something really compelling (which the NOCT just might do depending on price).

Jose Ribeiro's picture

I changed to Sony from Nikon 2+ years ago, currently on A7r3. For scene (TV, Movies etc) the silent mode is a must This was enough reason for the change. Eye autofocus is great.
If you need flash assist autofocus for events, then Sony A7 / A9 are a no go.
If you don't need silent mode there is no reason to change from Nikon or Canon to Sony.
Nikon has everything else better.

Deleted Account's picture

Having used SLRs since the very first Nikon F and being 76 years old and shooting since I was 11, I think I will stick with my 2 D500s and the D850 and leave the mirrorless cameras to people who shouldn't be looking in mirrors anyway.

Frank Pryor's picture

Hi Lee,

This question has been bugging me since I saw the D850 images at Dpreview: Can you speak to the real-world moire performance of the 850? I shoot primarily product photography and in the past I've had deal-busting moire produced by cameras in the 12~14 megapixel range when shooting packaging, tweed jackets or anything printed with a half-tone dot pattern. Morie from the 850 looks really bad in their test target image ( Note the wood-cut portion of the test target) but I wonder how this translates to actual working conditions.



Lee Morris's picture

It hasn't been a problem for me but I'm not shooting stuff that would cause morie anymore. I would check with a fulltime wedding photographer (someone who shoots people in fancy clothes) and they will be able to tell you if it's a problem.

Espen Grimstad's picture

Good stuff. Sealed the deal for me - not switching either. I am curious though to know what kit you'd would be carrying with you on a holiday for those quick, fun and decent quality snap shots? I've searched high and low and can't seem to land on a good overall (weight, size and quality vs cash) camera+glass that will allow me the holiday snaps and make ok'ish video.Closes I got was the Sony a6500, but the choice of glass was not impressive. HELP!

Jay Huron's picture

A battery grip takes care of the size and the battery life. (which really isn't that bad) I can shoot for a couple/ hours using the wifi mobile app running with the AR7ii. I'd think that would extend a couple more hours. Granted I could shoot for like 8 or more on a Canon 7D (no wifi, EVF, in body stabilization, sucking the battery down obviously) So as long as you are okay with swapping a battery twice as often it's not an issue. (or get the battery grip)
My biggest gripe with Sony is their ergonomics and menu. They need to take a page from Olympus' design team. They are amazing! (menus are okay)