Help with D850 Buffer Issue?

[tigger4t]

I use it on my z6 ii after having card hot warnings on my lexar 64gb cfexpress cards. Runs a lot cooler than the Lexar, ironically most noticeable on the Lexar cfexpress reader. I also tested it on my D500 after upgrading the firmware and works fine.
The D850 is a bit newer than the D500, so might even work a bit faster than on the D500. I am contemplating replacing the D500 with an used D850 as there are good deals to be had.

It is also a recommended card per Angelbirds compatibility checker for the D850.

Camera Compatibility

www.angelbird.com

Angelbird cfexpress cards are also the only cards with upgradable firmware afaik, with the catch being that you need an angelbird card reader to perform the update. There was several updates for older cards for better Z9 and D850/D500 compatibility.
The only complaints I have seen thus far was wit the Mk1 cards on the Z9, that have a not compatible rating on Angelbirds compatibility checker.

Fantastic - many thanks

 

[tigger4t]

Many thanks to everyone who has contributed - it's always good to get good first hand experiences to support what you've got from the manual

 

[tigger4t]

OK, so I'm definitely losing the plot now as someone from Wex Photo has just told me that the D850 cannot use cards bigger than 256GB so I still haven't cracked the seal on the 512Gb CFE card packaging yet! Can anyone confirm or contradict please as there is nothing in the manual that covers it.

Apologies, forget that - the Nikon website already shows cards up to 1Tb that have been approved. It would be good to hear if anyone has practical experience of a D850 with cards larger than 256Gb though as I am now getting slightly paranoid about opening the box.

 

[ButlerKid]

A Google search brought up this on the Nikon site......

Capacity of CFe cards goes up to 650 GB..................

 

[EricBowles]

A Google search brought up this on the Nikon site......

Capacity of CFe cards goes up to 650 GB..................

The Nikon site in the link above lists a number of cards, but it's just a fraction of the dozens of CFExpress cards available. Some of those cards are Approved (meaning Nikon actually tested them), but I would recommend you avoid them because they are slow (like Lexar CFExpress cards). Other cards recommended for the Z cameras - like Delkin Power, and Delkin Black - are not mentioned at all and work well in the D850.

Whatever you do, avoid the ProGrade Gold CF Express cards as I have tested and they are very slow in the D850.

 

[Patrick M]

The Nikon site in the link above lists a number of cards, but it's just a fraction of the dozens of CFExpress cards available. Some of those cards are Approved (meaning Nikon actually tested them), but I would recommend you avoid them because they are slow (like Lexar CFExpress cards). Other cards recommended for the Z cameras - like Delkin Power, and Delkin Black - are not mentioned at all and work well in the D850.

Whatever you do, avoid the ProGrade Gold CF Express cards as I have tested and they are very slow in the D850.

2nd on avoiding prograde . My cfexpress gold was so slow I called prograde to check, and all they did was confirm it was their latest, offered no further support, so they got the card and their card reader back by return. I hate not having support from the manufacturer.

 

[glsmith9823]

Having both a D850 & D500 & having switched from SD to XQD to CFExpress one clear factor I have noticed that is in the menu of the cameras is the image size (I believe it is marked as S, M, L of the image of what you are writing to your card. Before rushing out & buying a different card, try the following. Step 1 is Format the card. A lot of people do not. Even if images are removed off of cards software pointers remain. These occupy space and the new data does not overwrite the pointer (incredibly small), but it has to search for a new free spot & that adds to the time. Next, experiment with size of your raw images. The last culprit that I have seen & noticed my self is the setting in the menu (Custom Settings/Shooting Display) The Max continuous release is by default set to a super high number, I've turned mine way back to 35 or 40 shots. If you're shooting raw & large size the buffer may be trying to hold a super large amount of space that isnt there & as such has to wait to have data actually written to the card to free up to the buffer. Lastly, I didnt see it mentioned is if you have a second card and are using it as a backup, that may slow down things as well in writing to a card.

 

[O]

Fantastic - many thanks

SIMPLE:
Sorry i typed XQD instead of CF Express now corrected.

I also run when needed my Z9 Pro grade 325 gig 1700/1500 CF Express cards in the D850 (software upgraded for CF Express)
I run a Genuine Grip on the D850 with the D4s D5 even on occasions Z9 D battery.

If i use lossless raw 14bit i get a ridiculous impractical number of shots in a burst with a super long buffer that just makes no sense.

I hardly ever shoot raw, i shoot Jpeg fine 98% of the time in all cameras simply for me as Jpeg fine is just that good for what i do.
If its critical and really important then Raw is it or Tiff.

If you require lots of raw HC burst all the time then you have the wrong camera, your shutter use by will quickly run out, you need a Z9 or possibly a Z8 pending.

I find my D850 performs brilliantly with or with out the genuine grip, i use SD cards mostly, if i am doing any sports action wild life then i pop in a quality CF EXPRESS cards.
You can buy a level down from the 325gig Pro grade that will suite well.

Only opinion

 

[Roy]

Hi,

I have just bought a used Nikon D850 and shooting in Large RAW 14bit Lossless Compressed files it gives me only 14 shots in the buffer when I half press the shutter release so it's not even testing the transfer rate to the card - which is a 128Gb Sandisk Extreme SDXC 150 Mb/s. I have yet to buy an XQD card as I still have the D850 on 14 day approval but I am not aware the the transfer rate of the card is an issue as (a) I am not actually shooting and (b) when I tried a much slower SD card in the slot the buffer size stayed the same at 14.

By comparison, my D7200 gives me 19 frames in the buffer and my D800E gives me 14 using the same card. I know that the D850 has much bigger files but I would still expect some improvement over my older cameras if not the 51 according to the manual (albeit with an XQD card).

Is the camera actually taking the transfer speed into consideration before I shoot or do I have a problem?

**UPDATE** After a hard reset with the same image settings as above the D850 is giving me 27 in the buffer which reduces to 20 if I turn Auto-ISO on.

All advice gratefully received.

Simon

Going to an CFexpess or enen XQD card is another level of speed over any SD card.
The D7200 should hold more frames in the buffer - it has a much smaller sensor.
The bonus is that they are much more reliable...

 

[O]

2nd on avoiding prograde . My cfexpress gold was so slow I called prograde to check, and all they did was confirm it was their latest, offered no further support, so they got the card and their card reader back by return. I hate not having support from the manufacturer.

Did they give you your money back ?

I have no experience with the Pro Grade Gold CF Express other than being told they are more for landscape, portraiture, general travel shoots not necessarily fast wild life or fast sports action, as that's not what they where specifically intended for due to the limited speeds reflected in their price.

I have no issues with the 1700/1500 Pro Grade 325gig CF Express cards on the Z9 D6 or the D850, Nikon confirmed 1700/1500 Pro Grade 325gig was the perfect spec card for the Z9, Thom Hogan told me if i want to use 20fps raw on the Z9 i would need as a minimum this standard of card, I bought 3 pairs of CF Express 1700/1500 Pro Grade 325gig cards i cant fill the buffer using raw lossless compressed in any real world shooting application.

Only an opinion

 

[Patrick M]

Did they give you your money back ?

yes I got a full refund for both the card and reader. My biggest gripe was the total lack of interest from their support people. At the least I'd have expected them to replace to card so they could check it out. Nothing but a confirmation that it was the latest card. I tested quite extensively and in all aspects it was slower than my Sony XQD - hence there probably was a fault with the card.

 

[EricBowles]

Did they give you your money back ?

I have no experience with the Pro Grade Gold CF Express other than being told they are more for landscape, portraiture, general travel shoots not necessarily fast wild life or fast sports action, as that's not what they where specifically intended for due to the limited speeds reflected in their price.

I have no issues with the 1700/1500 Pro Grade 325gig CF Express cards on the Z9 D6 or the D850, Nikon confirmed 1700/1500 Pro Grade 325gig was the perfect spec card for the Z9, Thom Hogan told me if i want to use 20fps raw on the Z9 i would need as a minimum this standard of card, I bought 3 pairs of CF Express 1700/1500 Pro Grade 325gig cards i cant fill the buffer using raw lossless compressed in any real world shooting application.

Only an opinion

The 325 GB card is ProGrde Cobalt. That card is fine and is quite fast.

The Prograde Gold 128 GB CFExpress card is much slower. I tested it in a D850 and it was slower than my old Lexar 64 GB XQD and my Sandisk UHS-II 300 MB/s Extreme Pro SD card. The 512 GB size ProGrade Gold card is much faster than the 128 GB size and is probably acceptable.

The difference in these two ProGrade CFExpress cards is the sustained write speed. In a lab environment for a short period, the Gold card is okay. But putting it in a camera, by the time the buffer is full it slows to around 110 MB/s in my testing with a D850. That means the buffer fills very quickly and is slow to clear. In addition, it only resumes peak shooting speed when the buffer is completely cleared - not when you simply give it some time and free up space for a few seconds. It takes around 10-12 seconds to completely clear the buffer in the D850 with ProGrade Gold.

 

[Calson]

Buy a CFexpress card that will work well with the D850 and with the Z9 if you decide to buy one. There is also a good deal of difference in mage file size with the 14-bit Raw being 17% larger than 12-bit Raw with the D850. This in turn affects the files that can be held in the buffer of the camera.

 

[O]

yes I got a full refund for both the card and reader. My biggest gripe was the total lack of interest from their support people. At the least I'd have expected them to replace to card so they could check it out. Nothing but a confirmation that it was the latest card. I tested quite extensively and in all aspects it was slower than my Sony XQD - hence there probably was a fault with the card.

I found them to be somewhat blunt, short, i guess maybe the DSLR Mirror less market is really becoming a new or more significant market for them, maybe dealing with a lot of new consumer type of clients rather than the technical video cinema market may be a change for them.

I cant see how something so small can be so expensive..........

Only an opinion

 

[O]

The 325 GB card is ProGrde Cobalt. That card is fine and is quite fast.

The Prograde Gold 128 GB CFExpress card is much slower. I tested it in a D850 and it was slower than my old Lexar 64 GB XQD and my Sandisk UHS-II 300 MB/s Extreme Pro SD card. The 512 GB size ProGrade Gold card is much faster than the 128 GB size and is probably acceptable.

The difference in these two ProGrade CFExpress cards is the sustained write speed. In a lab environment for a short period, the Gold card is okay. But putting it in a camera, by the time the buffer is full it slows to around 110 MB/s in my testing with a D850. That means the buffer fills very quickly and is slow to clear. In addition, it only resumes peak shooting speed when the buffer is completely cleared - not when you simply give it some time and free up space for a few seconds. It takes around 10-12 seconds to completely clear the buffer in the D850 with ProGrade Gold.

Good to know
I didn't go for any other size or brand i bit the bullet LOL

When the CF Express cards were first being promoted for the Z9 there was a lot of controversy over brands and speeds even quality issues and so on, i just Took Toms advice and Nikon's advice and just got the 6 off The 325 GB card is Pro Grade Cobalt which meant no issues or mix ups on speed or capacity, each camera was set ready to go, yes a bit more expensive or over kill but when you spend $2000 each day on a chopper out west in the outback or the Kimberly's the last thing you want to be using is a card that's well ???not fast enough or possibly suspect or even short on video capacity as you jump from stills to video and back again.

My friend went to the Antarctica 12 days, 2 cameras he had lots of cheap cards, one battery charger, and half the batteries where after market, given the cold environment and dampness, strangely he had his charger fail, and lost exceptional images from a unique outing on 2 of the 6 cards he had, he complained that the aftermarket batteries didn't last long at all.

I asked him when he was going back he said, cant afford to do it again.........

Only an opinion

 

[EricBowles]

You have to be a bit careful with Nikon's "advice" about cards. The manual recognizes a few established brands without regard to any variation based on card size or other factors. Yes, a card may work, but it may not perform satisfactorily. A case in point is the ProGrade Gold cards which I found unacceptable at the most popular smaller sizes where buffer size or write speed are relevant. They also don't test very many cards and miss excellent cards such as the Delkin Power and Delkin Black. It takes months for Nikon to certify cards, and scope is limited. As a result, Nikon does not go back and add cards when larger sizes, new variations, or faster cards are available.

 

[O]

You have to be a bit careful with Nikon's "advice" about cards. The manual recognizes a few established brands without regard to any variation based on card size or other factors. Yes, a card may work, but it may not perform satisfactorily. A case in point is the ProGrade Gold cards which I found unacceptable at the most popular smaller sizes where buffer size or write speed are relevant. They also don't test very many cards and miss excellent cards such as the Delkin Power and Delkin Black. It takes months for Nikon to certify cards, and scope is limited. As a result, Nikon does not go back and add cards when larger sizes, new variations, or faster cards are available.

You are absolutely correct,

in my case, i better clear up the wording of my comment "Nikon recommended"

From the coal face, My Z9 arrived 24th December 2021, weeks before I spoke with NPS and asked, what is the optimum specification card required to best harness the full capabilities of the Z9 at 20 fps RAW lossless, they didn't mention a brand but mentioned read and wright speeds required, as did Thom to the same question, i then mentioned a few brands, and i did mention the Cobalt in particular, to which NPS said, it met the specification needed and was actually on their then short approval list, see the current extended list on the link below,

https://www.nikonimgsupport.com/ni/NI_article?articleNo=000044081&configured=1&lang=en_US

Thom said the read wright speed of the Cobalt I had listed at the time was the specification required if i want to achieve 20fps Raw.


I believe Pro Grade Cobalt, Delkin Black, Angel and Nikon's own Card seem to be the go top cards to day for the Z9 20fps raw.

On occasions I use the Cobalt in the D850 as well but for most of my applications using the D850 the Sand Disk SD card is fine.

Currently my needs and direction seem to be changing or evolving differently.

When i sell the Z9 i will include 2 of the 6 Cobolt cards.

Currently for everything else i do especially sports action and some wild life the D6 D850 more than meets my needs, i am not investing into doing video.

When i look at a photograph and cant tell if its the Z9 or D850 or D6 D3X i think its time to reflect and review. (pixel peeping excluded)

The Z9 is amazing, but if the most i am shooting at is around 10-12 fps its a bit of an overkill for what i am doing, to day i am focusing more on photography story telling, something that has been left behind lately.

I would like to go small light and focus on the glass rather than the camera's, i could wake up tomorrow morning and change my direction again LOL

I feel for me the Z8 if it lives up to expectations may be a better fitting shoe if it at least does 10-12 fps which i feel it will.

In answer the the original Thread regarding the D850 Buffer issue CF Express card is the answer if its not don't be a sprayer be a photgrapher or get the right camera to meet the needs.

Only an opinion

 

[tigger4t]

This is a test situation to determine whether the D850 is functioning correctly, nothing more, nothing less.

Set at Large Lossless 14bit RAW with an Angelbird 512Gb CFE card writing at 850 Mb/s I am still only seeing a buffer size of 20 shots with the D850 slowing down after about 32 shots. Is anyone able to tell me their D850 buffer size using a comparable card (a) after a full reset i.e. Large JPEG Normal and (b) with Large Lossless 14bit RAW. Angelbird tell me that the card is recommended for the D850 and it has the latest firmware as does the D850.

I get a buffer size of 55 for (a) and 20 for (b) whereas the manual says I should be getting 200 and 51 respectively with what I assume to be a slower Sony XQD card. The buffer size also stays the same whether I use the 850 mb/s CFE card or a much slower 150 Gb/s SD card. Everything I've read here and on other sites suggests that there is something wrong with the D850 and I'm now just trying to determine whether it needs to go back to the shop.

All constructive help appreciated but some validated figures for (a) and (b) above are really what I'm looking for please.

 

[EricBowles]

This is a test situation to determine whether the D850 is functioning correctly, nothing more, nothing less.

Set at Large Lossless 14bit RAW with an Angelbird 512Gb CFE card writing at 850 Mb/s I am still only seeing a buffer size of 20 shots with the D850 slowing down after about 32 shots. Is anyone able to tell me their D850 buffer size using a comparable card (a) after a full reset i.e. Large JPEG Normal and (b) with Large Lossless 14bit RAW. Angelbird tell me that the card is recommended for the D850 and it has the latest firmware as does the D850.

I get a buffer size of 55 for (a) and 20 for (b) whereas the manual says I should be getting 200 and 51 respectively with what I assume to be a slower Sony XQD card. The buffer size also stays the same whether I use the 850 mb/s CFE card or a much slower 150 Gb/s SD card. Everything I've read here and on other sites suggests that there is something wrong with the D850 and I'm now just trying to determine whether it needs to go back to the shop.

All constructive help appreciated but some validated figures for (a) and (b) above are really what I'm looking for please.

You should be getting 4-6 seconds at 7 fps before the buffer causes any slowing. At 32 frames that's the lower end of that range but sounds reasonable. Your indicator should initially show around 20 remaining and then gradually count down as the buffer fills. When it slows down depends on the card and file size. File size varies depending on the file type, scene you are photographing, and ISO. If Backup mode is used that would fill the buffer much faster.

Angelbird makes several types of cards and it's hard to tell them apart. Some are slow and others are faster. We need more details on the specific Angelbird card you are using. Is it the Angelbird Pro SE?

You are not going to get peak card speed in a D850. When the D850 was developed and configured, fast CFExpress cards did not exist, so the bus can't hit the sustained write speed Angelbid publishes. The top end write speed of the D850 is around 210 MB/s or less. That's around 3.2 fps written to the card, and the balance (round 3.8 fps) is in the buffer until the buffer fills.

I'm pretty sure the 200 / 55 frame numbers are using a 12 bit loss compressed file or a JPEG - you'll have to check the fine print. That's not a number for 14 bit lossless compressed.

I don't think it is a problem with the D850 outside of simply a hardware limitation. It's working properly.

 

[tigger4t]

Thanks Eric, it's interesting (and reassuring) to hear that the indicator should show 20 which is precisely what I get. The card is an AV Pro CFexpress SE Type B (800 Mb/s continuous and 850 Mb/s max). I guess it's a question of managing expectations as I had expected the D850 to have a much deeper buffer than my D800E even allowing for the much bigger file sizes on the basis that the D850 has always had such great reviews.

For JPEG Normal I get 55 against the Nikon manual's 200 and for Lossless 14 bit I get 20 against the manual's 51 - the only caveat they put on it is that the images count is at ISO100. I've attached the manual page below for info but it's odd that the differences are so great.

Time to put it to a real test with a trip over the weekend though - thanks again for your help.

 

[Bennvdm]

Per these older tests done on D850 & xqd, 30 uncompressed raw with Lexar 2933x Xqd, rated max write speed 400MB/sec - data right at the top.
Manual screenshot shows 29 for uncompressed 14bit raw.

Best Memory Cards For The Nikon D850 | Alik Griffin

A real world comparison between all the best XQD and SD (UHS-II) memory cards for the Nikon D850. All cards are tested in-camera to see which cards are the fastest and perform the best.

alikgriffin.com

Turn off image review when testing buffer, as it has a huge impact on buffer

I doubt that cfexpress will be faster on a D850 than a good QXD, but you should get similar speeds as likely limited by camera bus size etc.

 

[EricBowles]

Thanks Eric, it's interesting (and reassuring) to hear that the indicator should show 20 which is precisely what I get. The card is an AV Pro CFexpress SE Type B (800 Mb/s continuous and 850 Mb/s max). I guess it's a question of managing expectations as I had expected the D850 to have a much deeper buffer than my D800E even allowing for the much bigger file sizes on the basis that the D850 has always had such great reviews.

For JPEG Normal I get 55 against the Nikon manual's 200 and for Lossless 14 bit I get 20 against the manual's 51 - the only caveat they put on it is that the images count is at ISO100. I've attached the manual page below for info but it's odd that the differences are so great.

Time to put it to a real test with a trip over the weekend though - thanks again for your help.

View attachment 47010

When Nikon refers to the Buffer, they refer to the number of frames in a burst before the buffer fills and the camera has to slow. I think of that as Maximum Burst Length - but they call it buffer. When you look at your camera's display during a burst, the is a number of frames remaining shown. It's something like "r20" at the first shot, and gradually counts down as images fill the cache.

In my testing, I shot a 35 second burst and then counted the number of frames in each full second. You can use this simply by viewing the image detail information in the playback. The time the image was taken is shown in full second intervals. The initial images start in the middle of a single second even though it is at peak speed.

Depending on the card, my frames in each second are 4-7-7-7-7-7-4-5-4-5-6 etc. The initial 4 frames are over a fraction of a second. The 4 frames after the series of 7's is a partial or full second at peak rate. Keep in mind you can get some odd rounding and I'm only recording full seconds.

Here is a graph of the data from my D850 test with three cards. Your card should be faster than any of the cards I tested. The Lexar XQD card is actually pretty good in this camera. The vertical axis is the number of frames in a second. The horizontal axis is the sequential number of the one second interval in the burst.

You can only see EXIF info for this image if you are logged in.

I was testing three cameras and had to repeat tests on several occasions. Be sure you format the card in the camera before the test. It can be extremely slow if you have formatted it in a different camera. Be sure you are able to sustain a maximum frame rate of 7 fps at the beginning - there may be specific settings required to hit that speed. I tested on a tripod with a subject that had moderate detail so every image was about the same. My images were at ISO 100 to minimize noise and keep file size down to normal levels.

One finding I had with this testing was that once you fill the buffer, the camera does not return to peak frame rate until the buffer is completely cleared. That's true even if you pause for a few seconds and most of the buffer has cleared. It won't return to 7 fps until it is fully cleared.

 

[tigger4t]

Thanks Eric - that is extremely helpful, much appreciated. I guess that all comes back to controlling your burst length then.

 

[ButlerKid]

Thanks Eric, it's interesting (and reassuring) to hear that the indicator should show 20 which is precisely what I get. The card is an AV Pro CFexpress SE Type B (800 Mb/s continuous and 850 Mb/s max). I guess it's a question of managing expectations as I had expected the D850 to have a much deeper buffer than my D800E even allowing for the much bigger file sizes on the basis that the D850 has always had such great reviews.

For JPEG Normal I get 55 against the Nikon manual's 200 and for Lossless 14 bit I get 20 against the manual's 51 - the only caveat they put on it is that the images count is at ISO100. I've attached the manual page below for info but it's odd that the differences are so great.

Time to put it to a real test with a trip over the weekend though - thanks again for your help.

View attachment 47010

The virtues of the D850 are many.........but buffer wasn't one of them. Image quality, features, focus/tracking just a bit below the D5.....etc.

Go shoot the thing and enjoy it! LOL!

 

[O]

Hi,

I have just bought a used Nikon D850 and shooting in Large RAW 14bit Lossless Compressed files it gives me only 14 shots in the buffer when I half press the shutter release so it's not even testing the transfer rate to the card - which is a 128Gb Sandisk Extreme SDXC 150 Mb/s. I have yet to buy an XQD card as I still have the D850 on 14 day approval but I am not aware the the transfer rate of the card is an issue as (a) I am not actually shooting and (b) when I tried a much slower SD card in the slot the buffer size stayed the same at 14.

By comparison, my D7200 gives me 19 frames in the buffer and my D800E gives me 14 using the same card. I know that the D850 has much bigger files but I would still expect some improvement over my older cameras if not the 51 according to the manual (albeit with an XQD card).

Is the camera actually taking the transfer speed into consideration before I shoot or do I have a problem?

**UPDATE** After a hard reset with the same image settings as above the D850 is giving me 27 in the buffer which reduces to 20 if I turn Auto-ISO on.

All advice gratefully received.

Simon

I wonder if what your trying to achieve or expect is worth the effort,
Your wanting better buffer, faster auto focus i assume from what i am reading, and to know if the D850 you have is defective or not.

The D850 like any other camera is only a tool that fits a purpose for what it was designed for.

If you have the slightest concern about the D850 you have on loan take it back and get another one.

If the same lack of expectations exist then there are several possibilities to consider

1) use the best possible CF EXPRESS card you can afford
2) make certain the camera is formatted and set up optimally, especially with focus and release settings that can adversely effect focus speed and frame rates.
3) question your technique and what objective you have in mind and how the D850 tool fits that purpose.

Or get a genuine grip and use the D5 D6 Z9 battery for that boosted responsiveness in focusing attack speed and increased frame rate.

4) ask your self about your set up , your technique, what your doing, and if its all correct, then ask if the the D850 is the right tool.

I find the D850 flawless used and set up properly, i use it with out the grip and with the Grip, with the grip i use a D5 D6 Z9 battery, a CF Express card, in my case the Cobalt only because i have them from the Z9, i do find with the grip on the D850 the focusing attack speed seems slightly more responsive, the frame rate is faster, the buffer exceeds all my expectations for that tool and i never clog up in the buffer even in raw Lossless compressed HC 9FPS because i don't with my technique spray and shoot endlessly, also that's not what the the D850 was designed to do, the D850 does respectfully meets all my expectations wildly, i have zero issues buffer speed or focusing.

With the D850 I do birds in flight, wild life, sports action like soccer, surfing, rodeo, basket ball etc.
The right glass can also effect performance as we know.

If the D850 doesn't do what you want it to do and you have accessed your self first as doing all things correctly and your using the optimal card then you have the wrong tool.

If i need super fast focus attack speed with a series of demanding repetitive HC burst after burst then I use a D4s D5 D6, if i need that demanding performance at 45mp raw Lossless then i use a Z9, as its the right tool.

I give all these tools the right cards, settings and GLASS to match the APPLICATION as i do equally the D850......Happy Days no issues what so ever.

Again I find the D850 is brilliantly capable as an all rounder do everything well tool, i have even replaced my D4s and D5 with 2 x D850 units, one recently sold as i now have the Z9.

If i find the D850 doesn't meet the needs in an application which is rare, its not the cameras fault, its mine because i am expecting something from a tool it wasn't meant to do.

We can analyze, search, question, compare and overthink or over complicate the situation till the sun sets, its all horses for courses.

Example: I mean i like the Z9 20 fps 45mp good tracking, but gee i still love the D6 as its a different tool that for me in low light super fast indoor sports action or in very challenging conditions the D6 focus attack, tracking and stickiness simply is better than mirror less in any brand, now its a tool that i find fits better for that purpose yet that doesn't take away from the Z9 or other mirror less brands, the Z9 it offers other benefits like 20 30 fps 45mp etc, excellent video, i respect a tool for what it was designed to do, and the D850 is the best DSLR Nikon has ever made, used properly.

Only an opinion