I am headed to Alaska in a little over a week to photograph brown bears in Katmai NP. The trip leader recommends a 100-400 mm lens. When I made plans for this trip (almost 2 years ago and pre-covid), I had expected that the 100-400S lens in Z mount would be out by now. I also sold my 80-400 mm G lens (I had a good copy) last year. I plan to take a Z7II, Z6II and either a D500 or D850. I'm set on the shorter end (14-30 f4, 24-70 f4, and 70-200 f2.8 in Z mount). But still debating what to take for a longer lens or lenses.
I'm thinking about:
200-500 mm Nikon zoom. Good lens and a zoom, but a bit heavy (the PFs have spoiled me) and not the fastest AF. The zoom takes a fair amount of turning to go from the short end to the long end or back.
500 mm PF. My favorite lens, but no zoom flexibility and may be a bit long for many shots. So I could pair it with a 70-300 mm AF-P FX lens (on the D500 or D850) or the 70-200 f2.8 with a 1.4x TC in Z mount (on the Z6II) and carry two bodies/lenses on a double black rapid strap. (We will likely be shooting handheld most of the time.)
70-200 mm f2.8 with the 2x TC in Z mount, giving me a 140-400 mm f5.6 on a Z7II. Playing around with this combo some this week. Wonder how it will do with autofocus and fast action.
Any thoughts or suggestions?
For me I would Listen to "The trip leader recommends a 100-400 mm lens" this speaks volumes and gives you the answer your looking for already, my guess is that 200-300 will be the optimal range.
Your D850 or Z7II will give you an extra 200mm in crop ability if ever needed at all.
There are always to many choices or alternatives and it creates often a dilemma so we get dressed up like RAMBO take the whole bag full of stuff and use only very little.
The Kiss principal for me is the best I find.
I would take 2 lenses one camera one 1.4 TC as reserve, Light monopod.
The 70-200 2.8 step back or forward a little and you have added versatility length and F2.8 tack sharp on your Z7II or D850, you have speed sharpness fast accurate focus crop ability dynamic range, DX option in a heart beat of flicking a switch.
I would take a light mono pod and the 200-500 because while you wont be so far away all the time it will give you the option for tight compressed shots with great background blur.
2 lenses 70-200 and 200-500 on a FF 45mp you should kill it, remember 90% of the result comes from you not the gear.
I would carry a 1.4 TC for the 70-200 only if really needed.
The TCs work slightly better on a Z camera.
Forget about the weight of the 200-500 you will be so glad you took it. So many friends like their 500PF but complain about the lack of flexibility more often than not.
The worst thing I find is overthinking it makes things heaver when there not or makes issues where there aren't any.
If I jumped a plain tomorrow to do what your doing, I would use the D850/ Z7 II.
The 70-200 .......200-500 nothing else other than that 1.4 tc and a light mono pod.
I prefer versatility and have found it to be so much more successful especially if there are other creatures around to photograph.
Remember the Kiss principal[, cover 70-500 and sleep at night peacefully.
I would spend my time focusing and planning on composition tactic's, how can I get shots that are different to what everyone else takes.
Only an opinion
Oz down under