Which would you pick for birds

[ChrisM]

That is a real dilemma you have there.
I used the D500+500PF for a few years, waited for Nikon's A1 counterpart, and as the Z9 was too big and heavy for someone who likes to hike a lot and doesn't use a tripod or monopod, I decided to give Sony a go, sold my Nikon gear and went for the A1+200-600.

The Sony combo is fantastic, the A1 thé ultimate hikers wildlife body, I love everything about it, and it made me forget my D500 quickly. I also had the original Z7 for a while, but that made me yearn for the D500 that I sold so re-purchased it and sold the Z7. So for the body, I would absolutely go for the A1 and forget about the Z6(II)/Z7(II). The AF acquisition, reliability and full electronic shutter and EVF make for a superb user experience.

Lens wise though, even if the Sony 200-600G is an astounding lens for the money on the A1, I really miss the 500PF true prime quality rendering. The 200-600 is widely praised, but I am mostly impressed with its superb AF performance on the A1. It is sharp and has very nice IQ, but it does not have the prime lens pixie dust. The colors are saturated but don't have the subtle tones of the prime lenses, the contrast is quite ok in good light, but the micro contrast in more subtle light is definitely not prime lens quality. Also the bokeh is not what I was used to from lenses like the 500PF or the Sigma 500/4. I see the 200-600 as a nice versatile lens with great performance, but it is only temporary for me.

The step up lens wise is complicated with Sony, you have to spend really big, and will get really big. Nikon has the PF lenses. Looking forward, I think I would never truly like to use a 600mm f4GM lens, just too big and heavy with a TC on. The 800PF would be so much more enjoyable.

So I would choose the 800PF, and hang whatever body on it until Nikon let's the Z9 tech trickle down to a gripless and affordable Z7III or whatever it's going to be.

 

[Snapquacky]

Well, you are posing a decision problem with a lot of constraints. If I were jumping into a new system, I would choose the Sony since the A1 is so good and Sony equipment seems more available.

But they don't have the lens you require. Nothing beats filling the frame for quality images.

For static birds, the image quality of the Z6/7ii will be as good as any mirrorless available. The Z6ii has the better low-light focus, but the image quality of the Z7ii can be better in good light, and if you can get a focus lock, programs like DeNoise in post-processing can pretty much equalize the picture quality if the light is low. (If you can't get a focus lock with either of these cameras then the light is low indeed, and maybe better to shoot another day.)

By the time you get the hang of the 800mm, which will probably have a big learning curve (don't be fooled by Steve Perry's video where he makes everything look easy), there will be a realistic stacked sensor Nikon body for your next financial conquest. And Nikon seems to be on track to providing high-quality, professional lenses at more affordable prices, and particularly at the long focal length.

On switching to the Z system, I retired some screw-drive lenses that were 20 to 30+ years old. Lenses really do outlast bodies so I would put the premium on buying the lens you really want.

Thanks John, you might have nailed it re the A1, it is so good, this has quite an influence on such a decision. You are right of course regarding lenses, I have an old 80-200 f2.8 Nikon, even older 300 f4, along with 35mm f2 and a few others, they almost always out class the body to which they are attached.

Interestingly my current 300 f4 even with a TC1.7x attached gives me 510mm, this is on crop sensor, theoretical 765mm if you multiply by 1.5, if my bizarre math is correct then that is about the field of view the 800PF would give on full frame sensor. That is interesting because even at 510mm it never seems that close to me, in fairness I really only use the 300f4 with 1.4x converter since the 1.7x is poor. I can see why even on a 600mm focal length people still add a 1.4x converter, particularly on full frame.

Plenty of food for thought here, I do appreciate all the input, it helps a lot.

 

[Snapquacky]

That is a real dilemma you have there.
I used the D500+500PF for a few years, waited for Nikon's A1 counterpart, and as the Z9 was too big and heavy for someone who likes to hike a lot and doesn't use a tripod or monopod, I decided to give Sony a go, sold my Nikon gear and went for the A1+200-600.

The Sony combo is fantastic, the A1 thé ultimate hikers wildlife body, I love everything about it, and it made me forget my D500 quickly. I also had the original Z7 for a while, but that made me yearn for the D500 that I sold so re-purchased it and sold the Z7. So for the body, I would absolutely go for the A1 and forget about the Z6(II)/Z7(II). The AF acquisition, reliability and full electronic shutter and EVF make for a superb user experience.

Lens wise though, even if the Sony 200-600G is an astounding lens for the money on the A1, I really miss the 500PF true prime quality rendering. The 200-600 is widely praised, but I am mostly impressed with its superb AF performance on the A1. It is sharp and has very nice IQ, but it does not have the prime lens pixie dust. The colors are saturated but don't have the subtle tones of the prime lenses, the contrast is quite ok in good light, but the micro contrast in more subtle light is definitely not prime lens quality. Also the bokeh is not what I was used to from lenses like the 500PF or the Sigma 500/4. I see the 200-600 as a nice versatile lens with great performance, but it is only temporary for me.

The step up lens wise is complicated with Sony, you have to spend really big, and will get really big. Nikon has the PF lenses. Looking forward, I think I would never truly like to use a 600mm f4GM lens, just too big and heavy with a TC on. The 800PF would be so much more enjoyable.

So I would choose the 800PF, and hang whatever body on it until Nikon let's the Z9 tech trickle down to a gripless and affordable Z7III or whatever it's going to be.

Thanks Chris, very interesting indeed, this scenario is something I have played out in my head to some degree. I like the idea of a 200-600 for flexibility, but, in my mind I know the prime is the real goal, in reality I cannot justify one of the new generation 600 f4 lenses, even the 800PF is pushing it for hobby use, but $6200 is a whole lot better than $10000+. I guess the temptation is to go with the stacked sensor body and cheap out on the lens to some degree, reality should be the opposite, go all in on the lens and settle on a body.

Your comments on the 500PF rendering are useful, 200-600 does seem incredible for focus speed with the A9 and A1, my only slight concern with the 800PF actually, maybe this is a non issue, for video it could come into play more.

Seems like I should be considering 800PF and Z6 or Z6ii, that body might help overcome the lower light and 6.3 aperture, allow me some more room with ISO. Much as I like the high resolution sensors, could be that I look at one further down the road, when the tech trickles down as you say.

Appreciate the experience and feedback.

 

[John Navitsky]

also consider... waiting a bit longer. if, as you say, you focus on static birds, the z6ii/z7ii are going to be totally fine. however, i'm skeptical you really _mean_ that. as a nikon guy, i'm very reluctant to recommend the z6ii/z7ii for folks who have difficult af needs. one thing to consider is.. the z6ii/z7ii af situation _will_ change in the not hugely distant future. probably with the z6iii/z7iii or similar body, but also _possibly_ through a firmware update.

if you need something now, and you can really hold to that static bird statement, the z6ii/z7ii is going to be fine. if you fear you don't really mean it, the a1 is going to be the better bet.

 

[ChrisM]

Thanks Chris, very interesting indeed, this scenario is something I have played out in my head to some degree. I like the idea of a 200-600 for flexibility, but, in my mind I know the prime is the real goal, in reality I cannot justify one of the new generation 600 f4 lenses, even the 800PF is pushing it for hobby use, but $6200 is a whole lot better than $10000+. I guess the temptation is to go with the stacked sensor body and cheap out on the lens to some degree, reality should be the opposite, go all in on the lens and settle on a body.

Your comments on the 500PF rendering are useful, 200-600 does seem incredible for focus speed with the A9 and A1, my only slight concern with the 800PF actually, maybe this is a non issue, for video it could come into play more.

Seems like I should be considering 800PF and Z6 or Z6ii, that body might help overcome the lower light and 6.3 aperture, allow me some more room with ISO. Much as I like the high resolution sensors, could be that I look at one further down the road, when the tech trickles down as you say.

Appreciate the experience and feedback.

The Sony 200-600 is carrying a lot of weight on its shoulders, since it is the only solution south of the 600GM. It is put on a pedestal now and then. It is a very fine lens, but don't expect prime level rendering. It is a compromise lens regardless of what is said, but a very good one if you are willing to give up the prime level pixie dust. It takes more than an afternoon to really get to know the 200-600G, but only go that route if you are willing to live without prime lens rendering.

I hope Sony is looking closely at Nikon, their new 400mm f4.5 will knock it out of the park again no doubt. There is room for lenses inbetween the 200-600G and the 600GM, a lót of room.

 

[Snapquacky]

also consider... waiting a bit longer. if, as you say, you focus on static birds, the z6ii/z7ii are going to be totally fine. however, i'm skeptical you really _mean_ that. as a nikon guy, i'm very reluctant to recommend the z6ii/z7ii for folks who have difficult af needs. one thing to consider is.. the z6ii/z7ii af situation _will_ change in the not hugely distant future. probably with the z6iii/z7iii or similar body, but also _possibly_ through a firmware update.

if you need something now, and you can really hold to that static bird statement, the z6ii/z7ii is going to be fine. if you fear you don't really mean it, the a1 is going to be the better bet.

Thanks John, you are probably right to be sceptical, I could live with focus suitable for static only but would very much like a stacked sensor, with all the goodness it brings! long term at least. I wonder how much difference firmware will make to the z6 and z7 range going forward, if Nikon gets their algorithm nailed down.

 

[John Navitsky]

I wonder how much difference firmware will make to the z6 and z7 range going forward,

many of us wonder that, and many of us have _hopes_, but we need to be willing to accept the answer *may* be zero. but... there will cameras below the z9 with significantly improved af over the existing z6ii/z7ii, it's just a matter of when and how. that is to say, i wouldn't buy a z6ii or z7ii with the _expectation_ that it will get substantially better via fw.

 

[Paul T]

Can I suggest and if within your budget and time frames to hire both combinations for a week or two. At least then you can make your final purchase decision based on personal experience.

 

[Snapquacky]

Can I suggest and if within your budget and time frames to hire both combinations for a week or two. At least then you can make your final purchase decision based on personal experience.

Thanks Paul, that is a sensible suggestion, unfortunately it isn't easy for me to hire and the cost would eat into resale profit, if I were to move the kit on short term. I plan not to be in that position, would like to think this purchase will be lasting me 5-6 years or more, hopefully 8-10 years based on my last camera. Logically I should wait for Nikon to get their 200-600 and Z8 released but you can keep waiting for new releases, I have been doing this in many respects since the D500 in fact. I was going to pickup a D850 then Z6/7 happened and the waiting began again never ending cycle which I hope to end this year

 

[BLev65]

I just finished reading the majority of the posts, and it does not look like anyone articulated the key difference in your decision process. As an advanced level biology teacher who views the nature of life through an evolutionary and ecological "lens," I often break most decisions into a more objective frame. As such, much like the evolutionary process, your decision relies on a rather sterile "cost/benefit" analysis.
In life, energy and reproductive output determine the retention of most phenotypes (traits), in your decision, things boil down to your personal "value" per dollar spent. Your budget is around $8000 for a birding kit. This should not be understated, as $8000 (US) is not a trivial amount of money to most people. You need to ask yourself... for that amount of money, what do you value the most? If you value camera functionality and responsiveness, then the Sony A1 (from your option set) is the way to go. If, on the other hand, you value best in class optics that are unique to the 800mm PF, then the Nikon kit is your best option.
To be clear, your Sony kit WILL get you the "shot" and probably result in more keepers per outing. On the other hand, when "nailed," the Nikon kit will yield best in class sharpness... though you will likely have fewer images from which to choose.

Final point... if you were to have $8500 to spend, and this was a long-term decision, it might be better to entertain other options to compare with the Sony. I shoot Nikon, but given the stark choice you've presented, I'd probably go with the Sony set.
On the other hand, for a budget of $8500, I personally would game out what the Z9 + "best lens", R5 + "best lens," vs A1 vs "best lens." As someone who has been shooting the Z9 for a few months now, I completely understand how the new tech in high end cameras have revolutionized our ability to capture fleeting moments.

regards,
bruce

 

[Snapquacky]

I just finished reading the majority of the posts, and it does not look like anyone articulated the key difference in your decision process. As an advanced level biology teacher who views the nature of life through an evolutionary and ecological "lens," I often break most decisions into a more objective frame. As such, much like the evolutionary process, your decision relies on a rather sterile "cost/benefit" analysis.
In life, energy and reproductive output determine the retention of most phenotypes (traits), in your decision, things boil down to your personal "value" per dollar spent. Your budget is around $8000 for a birding kit. This should not be understated, as $8000 (US) is not a trivial amount of money to most people. You need to ask yourself... for that amount of money, what do you value the most? If you value camera functionality and responsiveness, then the Sony A1 (from your option set) is the way to go. If, on the other hand, you value best in class optics that are unique to the 800mm PF, then the Nikon kit is your best option.
To be clear, your Sony kit WILL get you the "shot" and probably result in more keepers per outing. On the other hand, when "nailed," the Nikon kit will yield best in class sharpness... though you will likely have fewer images from which to choose.

Final point... if you were to have $8500 to spend, and this was a long-term decision, it might be better to entertain other options to compare with the Sony. I shoot Nikon, but given the stark choice you've presented, I'd probably go with the Sony set.
On the other hand, for a budget of $8500, I personally would game out what the Z9 + "best lens", R5 + "best lens," vs A1 vs "best lens." As someone who has been shooting the Z9 for a few months now, I completely understand how the new tech in high end cameras have revolutionized our ability to capture fleeting moments.

regards,
bruce

Thank you kindly Bruce, very interesting viewpoint, I will read over this again later when my workload drops off a bit. I like your Z9 + "best lens", R5 + "best lens," vs A1 vs "best lens" idea. Much as I know settling on a non stacked sensor is not a massive problem, I'm very keen to step into this new tech after living with average focus for both still and tracking.

Suspect putting together best options ignoring the price initially would be a sensible plan, then filter from there.

Side note, some excellent images on your website, will look through some more later.

 

[ChrisM]

I just finished reading the majority of the posts, and it does not look like anyone articulated the key difference in your decision process. As an advanced level biology teacher who views the nature of life through an evolutionary and ecological "lens," I often break most decisions into a more objective frame. As such, much like the evolutionary process, your decision relies on a rather sterile "cost/benefit" analysis.
In life, energy and reproductive output determine the retention of most phenotypes (traits), in your decision, things boil down to your personal "value" per dollar spent. Your budget is around $8000 for a birding kit. This should not be understated, as $8000 (US) is not a trivial amount of money to most people. You need to ask yourself... for that amount of money, what do you value the most? If you value camera functionality and responsiveness, then the Sony A1 (from your option set) is the way to go. If, on the other hand, you value best in class optics that are unique to the 800mm PF, then the Nikon kit is your best option.
To be clear, your Sony kit WILL get you the "shot" and probably result in more keepers per outing. On the other hand, when "nailed," the Nikon kit will yield best in class sharpness... though you will likely have fewer images from which to choose.

Final point... if you were to have $8500 to spend, and this was a long-term decision, it might be better to entertain other options to compare with the Sony. I shoot Nikon, but given the stark choice you've presented, I'd probably go with the Sony set.
On the other hand, for a budget of $8500, I personally would game out what the Z9 + "best lens", R5 + "best lens," vs A1 vs "best lens." As someone who has been shooting the Z9 for a few months now, I completely understand how the new tech in high end cameras have revolutionized our ability to capture fleeting moments.

regards,
bruce

I may not have formulated as well as you, but your post is very much in line with how I see it: the A1 when the camera counts most, the 800PF when the lens counts most. But I am now thinking there is a viable third option. The coming 400mm f4.5 appears to be a spectacular lens going by the previews, and that lens on a Z9 with the Z1.4TC might just beat the Sony kit optically, whilst staying close to the budget, and being 560mm f6.3.

 

[BLev65]

Thank you kindly Bruce, very interesting viewpoint, I will read over this again later when my workload drops off a bit. I like your Z9 + "best lens", R5 + "best lens," vs A1 vs "best lens" idea. Much as I know settling on a non stacked sensor is not a massive problem, I'm very keen to step into this new tech after living with average focus for both still and tracking.

Suspect putting together best options ignoring the price initially would be a sensible plan, then filter from there.

Side note, some excellent images on your website, will look through some more later.

Thank you for your kind comment about my website. I am working on a new gallery that will encompass the two pandemic years... I hope to post it by this time next week.
Good luck w/ your choice.

 

[Snapquacky]

I may not have formulated as well as you, but your post is very much in line with how I see it: the A1 when the camera counts most, the 800PF when the lens counts most. But I am now thinking there is a viable third option. The coming 400mm f4.5 appears to be a spectacular lens going by the previews, and that lens on a Z9 with the Z1.4TC might just beat the Sony kit optically, whilst staying close to the budget, and being 560mm f6.3.

The 400 will be on the short side for me, especially on full frame, a native 500mm would possibly work. There is no doubt that A1 and 800PF seem to be the two rising to the top here, my heart says Nikon can catch up with Sony for tracking etc, my head says it might take them another year or two. It makes sense that they are behind, Sony had a head start, they also make the sensors which does give them an advantage.

 

[Snapquacky]

OK, just thinking out loud and with some help from @BLev65 my options from the big three:

Z9 + "100-400Z" = $7400
R5 + "RF 800mm" = $4200 ($5200 non grey market) maybe this should be an R3 + RF 800mm ($6000) but resolution is lower than the Z9 and A1.
A1 + "200-600G" = $6500 ($8000 non grey market)

These are specifically based on budget of around $7500-8500, native lenses only. Best prices on all kit for my area, including grey market R5 and A1.

Interestingly Canon are very limited on any higher quality long lenses, in this budget! and Nikon really only have the 100-400 at the moment, so until Nikon let the 200-600Z out of the bag, for the longer end I would say Sony are still ahead within the budget above. Again, this is quite specific and using flagship (exception the R5, see above) bodies from all three.

I guess on the long end at 600mm this is a win for the Sony bundle. Being honest with myself, even when the Nikon 200-600z arrives, I am hesitant about whether it will really top the Sony offering, hopefully Nikon prove me wrong, just a hunch on my part. Canon clearly have some catching up to do with their tele range though.

 

[Calson]

For most wildlife photographers the best choice is Sony which has a very wide range of lens that are available to buy today. It is also easier to get two of the same model camera which I greatly prefer. I often have a super telephoto on one camera and a zoom telephoto on a second camera, like the 600mm with a 100-400mm for example.

Something I liked with my D850 cameras was the ability to use a battery pack grip that could take a full size pro level battery. With mirrorless this is not an option from any manufacturer which is one reason I chose the Z9 camera. Having 3-4 times as many shots per battery is great in the field but terrific when traveling as I can put a battery in the charger and grab it in the morning. With smaller batteries I either need a power strip and multiple chargers or keep checking the batteries and when fully charged put another battery in the charger.

 

[John Navitsky]

Being honest with myself, even when the Nikon 200-600z arrives, I am hesitant about whether it will really top the Sony offering,

not trying to start a thing, but i think you're wrong. imo the nikon 100-400 is (incrementally) better in every way over the sony 100-400 which is a very good lens. whoever is last has the advantage and nikon is taking no prisoners when it comes to glass. there is no way the nikon 200-600 is going to fall short of the sony 200-600. ymmv

 

[Snapquacky]

not trying to start a thing, but i think you're wrong. imo the nikon 100-400 is (incrementally) better in every way over the sony 100-400 which is a very good lens. whoever is last has the advantage and nikon is taking no prisoners when it comes to glass. there is no way the nikon 200-600 is going to fall short of the sony 200-600. ymmv

Thanks John, like I said, hopefully Nikon prove me wrong and the 200-600z is both sharper and faster focusing. If I was running Nikon then I would make the 200-600z the best bar none, fastest focus motors, sharpest glass, best bokeh, end of story. But, I ask myself this question, why would Nikon do this, in my logical mind it makes total sense, I suspect Nikon might have other ideas, budget will likely come into play along with some separation from the 400f4.5, 800PF and future 600f4.

I want to be wrong, more than most people I'm hoping Nikon knock it out the park with this lens

 

[Snapquacky]

For most wildlife photographers the best choice is Sony which has a very wide range of lens that are available to buy today. It is also easier to get two of the same model camera which I greatly prefer. I often have a super telephoto on one camera and a zoom telephoto on a second camera, like the 600mm with a 100-400mm for example.

Something I liked with my D850 cameras was the ability to use a battery pack grip that could take a full size pro level battery. With mirrorless this is not an option from any manufacturer which is one reason I chose the Z9 camera. Having 3-4 times as many shots per battery is great in the field but terrific when traveling as I can put a battery in the charger and grab it in the morning. With smaller batteries I either need a power strip and multiple chargers or keep checking the batteries and when fully charged put another battery in the charger.

Very valid points Calson, additional batteries are not a show stopper but carrying them isn't ideal, neither is charging them as you pointed out.

 

[John Navitsky]

If I was running Nikon then I would make the 200-600z the best bar none, fastest focus motors, sharpest glass, best bokeh, end of story.

if you look at the various z-mount glass, and the s-line in particular, i think this is more or less nikon's strategy when it comes to glass. all their z-mount glass is at the very least very good, and the s-line glass even more so.

But, I ask myself this question, why would Nikon do this, in my logical mind it makes total sense, I suspect Nikon might have other ideas,

it'll likely be best of class, where "class" is an important part of the phrase. it'll likely be better than the sony 200-600 (ie, the class leader), but it's not going to be better than a 600 f/4 s-line.

 

[BLev65]

OK, just thinking out loud and with some help from @BLev65 my options from the big three:

Z9 + "100-400Z" = $7400
R5 + "RF 800mm" = $4200 ($5200 non grey market) maybe this should be an R3 + RF 800mm ($6000) but resolution is lower than the Z9 and A1.
A1 + "200-600G" = $6500 ($8000 non grey market)

These are specifically based on budget of around $7500-8500, native lenses only. Best prices on all kit for my area, including grey market R5 and A1.

Interestingly Canon are very limited on any higher quality long lenses, in this budget! and Nikon really only have the 100-400 at the moment, so until Nikon let the 200-600Z out of the bag, for the longer end I would say Sony are still ahead within the budget above. Again, this is quite specific and using flagship (exception the R5, see above) bodies from all three.

I guess on the long end at 600mm this is a win for the Sony bundle. Being honest with myself, even when the Nikon 200-600z arrives, I am hesitant about whether it will really top the Sony offering, hopefully Nikon prove me wrong, just a hunch on my part. Canon clearly have some catching up to do with their tele range though.

I have shared the following advice with my workshop clients in the past...
The best bang for the buck wildlife kit WAS the D500 and 200-500VR. At the time, you could get both for $2500-$3000
As soon as Fuji releases their 150-600 f/8, the Fuji XH2s + 150-600 will be the highest performing wildlife kit per dollar spent.

Once you examine the "best" overall camera, things become very complicated.
Were I to enter nature photography today, or to ignore my years with Nikon, the Sony A1 + 200-600G is the best "starting kit," for the amount it costs to "play."
If you believe the R5 is your best option, then you should look for an EOS lens that can be adapted. The 400 DO ii is readily available for $3500-4500. I've seen EF 500mm f/4 IS (i) for as low as $2800. If you want to stay in the RF family, then consider the 100-500 over the 800mm DO. Canon's RF DO lenses are entry-level "also" lenses.
Nikon currently has only one mirrorless camera that could be at the center of your kit... the Z9. Your point of compromise will need to be like the RF system. While the 100-400 S is a marvelous lens, it is not for the birds. Unless you have a blind where you can coax your subject to be closer, you will want to have a 500m (+) lens. Here the adapted 500PF is a great option. The latter is permanently mounted to my Z9 until I can either afford the 400mm f2.8 w/ built-in converter, or Nikon develops a professional quality lens that approaches 600mm. My alternative would be the 800PF, but I fear that this is too long for the way I see and photograph the world.

I know many people who shoot and own the A1/200-600 combination... there is almost no sacrifice if you choose to go that route.

regards,
bruce

 

[bleirer]

I don't think the Canon rf800 is in the same ballpark. A fixed aperture f11 lens. The rf100-500 perhaps with a 1.4 tc would be more in the ballpark.

 

[ElenaH]

@Snapquacky , I've read almost all and would like to share my thoughts.
You wrote you have old screw-driver lenses from Nikon. I have 180/2.8, for exaple and I must say that there are no such lens like old Nikon screw-driver lens in terms of colour and overall rendering. Yes, they have horrible CA's and cannot focus on mirrorless but they give a special look : the saturated deep colours, sharpness (oh, yes, they are sharp) and some kind of 3D-effect.

So, 800PF is closer to those lenses than 200-600 of Sony. My partner has Sony A7R IV and 200-600 and Z9+800PF. After he has got 800PF, he doesn't use Sony anymore. Moreover, he has 400mm/2.8 FL (F-mount excellent lens) which he used with TCs and now he doesn't use it anymore, too. What is good for me ;-) becasue I can use it. Bur 800PF focuses much better/faster on Z9 than Z9+400FL and I think that Z9+800PF is overall better than Z9+400FL+2xTC. So, 800PF is amazing lens.

So, what I want to say is that you'd think what you like more: the look of pictures shoot by Sony or Nikon. Let's say you will buy Sony and don't like the pictures (the bokeh of 200-600 is so "olalala...," for example), than you spent your money and perhaps, you are not unhappy but don't have so much joy and fun like you would with 800PF (what I can guarantee - you will have a LOT of joy)

Perhaps you should rent both combilation and try.

The other thoughts are about Z7 vs Z6. If you take pictures of birds than normally there is already light or there is a short period of dusk. Normally. the birds sleep at night (ok, if you will take pictures of owls than it is different). And there is an excellent software to reduce the noise. I think, the noise will not be an issue but more pixel is better.
If your ever want to take part on some photo-contest then you need a high-resolution camera. The requirements for picture-resolution for contests are very high. So, I would go for Z7. If you additionally do some other kind of photography like astro or nightscapes then Z6 will be better.

 

[Snapquacky]

I don't think the Canon rf800 is in the same ballpark. A fixed aperture f11 lens. The rf100-500 perhaps with a 1.4 tc would be more in the ballpark.

I agree totally Bleirer, but it is the only native lens Canon have which is close, this is why I also left the Nikon 500PF out of the equation, trying to stick with native lenses.

 

[Snapquacky]

I have shared the following advice with my workshop clients in the past...
The best bang for the buck wildlife kit WAS the D500 and 200-500VR. At the time, you could get both for $2500-$3000
As soon as Fuji releases their 150-600 f/8, the Fuji XH2s + 150-600 will be the highest performing wildlife kit per dollar spent.

Once you examine the "best" overall camera, things become very complicated.
Were I to enter nature photography today, or to ignore my years with Nikon, the Sony A1 + 200-600G is the best "starting kit," for the amount it costs to "play."
If you believe the R5 is your best option, then you should look for an EOS lens that can be adapted. The 400 DO ii is readily available for $3500-4500. I've seen EF 500mm f/4 IS (i) for as low as $2800. If you want to stay in the RF family, then consider the 100-500 over the 800mm DO. Canon's RF DO lenses are entry-level "also" lenses.
Nikon currently has only one mirrorless camera that could be at the center of your kit... the Z9. Your point of compromise will need to be like the RF system. While the 100-400 S is a marvelous lens, it is not for the birds. Unless you have a blind where you can coax your subject to be closer, you will want to have a 500m (+) lens. Here the adapted 500PF is a great option. The latter is permanently mounted to my Z9 until I can either afford the 400mm f2.8 w/ built-in converter, or Nikon develops a professional quality lens that approaches 600mm. My alternative would be the 800PF, but I fear that this is too long for the way I see and photograph the world.

I know many people who shoot and own the A1/200-600 combination... there is almost no sacrifice if you choose to go that route.

regards,
bruce

Thank you Bruce, appreciate the input greatly. Fuji have some interesting cameras, I was not totally aware of this, let alone realising they were using stacked sensors! Nikon and Canon certainly have a good collection of longer lenses, especially if you include the 'pre-mirrorless' options, I suppose for this example I was trying to stick with native mount glass only, to keep things even.

I totally agree that 400 is not enough for birds, another reason I dismissed the upcoming Nikon 400f4.5. Like you I have reservations with the 800PF, if subjects are closer, you have nowhere to go, well, other than backwards very quickly! I can see how the 500PF would work well at the moment on the Z9, no doubt the future Nikon 600f4 will be a monster, potentially with a built in TC, surely this will be $12000-15000 also.

It seems that right now if you want 600mm native, then the Sony bundle still looks quite favourable.