Please tell me to NOT buy 600mm TC. Please. I have it sitting in a cart for last 3 hours ready to press button. I love my 800PF, but... Please tell me I'm wrong to dump $14K on something that is just marginally better but heavier. Please. I hate Nikon for these rebates.
I was agonizing last time Nikon did it, but this time it's much worse - we will never see this price again. Ever.
Would you use 600 at f4 and then 840 for most of your shooting if you had it?
Can you part with $14k and be fine? If you're here fretting about it, I assume you can afford it and also really want it...
While I am often using mine at F5.6-f8 at 600mm, I also am sometimes using the 840 at f5.6. Aside from the aperture, there IS the convenience factor of a very sharp prime+TC by way of a 2 second flip of your middle finger. How can this even be compared in practice to anything but a zoom yet none of the zooms have the other benefits of the lens? While they do have their own benefits of course.
For example, I have many times used 600 to gather a subject, then flipped to 840 as it lands or I have solid tracking locked. Or I might be tracking from farther, at 840mm, then as it gets closer, flip to 600. I just find it very versatile.
I think if cost were the same as the other options, many more people would utilize these benefits. When choosing equipment, since the mid 90's, I have always tried to first identify what would make my work or product better or more efficient or at least more enjoyable in some way, then figure out how to warrant it or pay for it.
I am fortunate that most of my stuff had some direct cost benefit as well if it could be more efficient or deliver something that another option could not, and therefor justify a higher $ cost up front.
Then, there are in fact benefits of the other lens options such as very practical aspects like size and weight both for packing but also viable movement through the course of a day. I have a Z9+Z 600 f4 TC on me for hours, walking, crouching, lying down, scrambling a bit and it's not fun after about 2 hrs LOL.
When I instead have an incredibly lighter kit like the Canon R5ii+RF 100-300/2.8, I am amazed at how nimble I feel. In fact at a bike race I had that and then the canon RF 24-15+R1 on my chest.
Usually one in the holster at my sternum and the other in hand. With the Z9+600TC, I'm pretty much just using that in front of me and anytime walking its set into the climbing holster I use while in a backpack is the Canon EF 200-400/4 TC and a body like the Z8 or R5ii.
With $ as no object, one can easily see the use case for having the Z 600/4 TC as well as other options like the 100-400 or maybe the 600/6.3 simple because of the reasons mentioned above.