For BIF, my two primary lens setups with my D500 were the 200-500 and an older 300mm AF-S w/1.4TC (the latter being my hand holdable combination). Now that I have a Z6III, and my wallet is unfortunately a bit slimmer, I had initially planned to try the 200-500 with the new body for another season to see if I was still unhappy with the lens being slow to acquire focus (my biggest gripe with the 200-500 when using it on my D500). But I have seen a few used lenses come up for sale that are making me reconsider and possibly make my wallet even slimmer. They are:
--Ken
- a used Z-mount 100-400
- a used 500PF
- a new 180-600
- Now that I am shooting FF w/a 24MP sensor, I no longer have the crop factor to give me a bit more reach. Yes, I can crop a bit into the image, but the DX equiv. on the Z6III is less than 11MP.
- If I get the 500PF, I can still use it on the D500, and most of my birding is done at 500mm. And I still have the 300mm and a 70-200 VRII as well, so I can shoot in either mount with these lenses.
- The Z-mount 100-400 would be a good compliment to my 24-120, and give me a nice range, but it does top out at 400 unless I pick up a 1.4TC.
- The 180-600 give me the greatest reach, but it is large and I worry that its AF acquisition speed will be similar to the 200-500, and I'd rather not continue with that if possible.
- All three options are about the same price, and I could trade in the 200-500 to soften the blow to my wallet if need be
--Ken