Originally Posted by
billtils
This is not a case of "NAS", but rather an admission of getting older! I find my 150-600mm lens is now a burden rather than a delight because of its over 2kg weight and it has to go.
The only reasonable alternatives in terms of weight, reach, and a recreational budget appear to be the Nikon AF-S 300mm f/4E PF ED VR with a 1.4x TC, and Nikon 70-300mm f/4.5-5.6E VR AF-P FX. Both are under a kilo and the PF is getting great reviews. However, it is a prime (or 2 primes with the TC option). When I look at my catalogue, most of my keepers are in the 300 to 450mm range so it should do, but it would leave a gap between 100 and 300 with the remaining lenses, and a birding buddy asked me "what would you do about the bird that's flying towards you"?. That gap would be filled with the 70 - 300, the VR AF-P version of which also gets good reviews, but I have the previous generation and it is not good enough at over 200 to be a serious replacement for the big Tamsron. The new one seems much better but according to Nikon it is not compatible with the TC so is out ...
... unless I change the body to a D500. Having gone from a crop (D7100) to the FF D750, the very idea would have been unthinkable until now, but looking at the D500 reviews it seems to have exceptional IQ, even at very high ISOs. It also has a fast burst rate and very large buffer capacity.
All comments and advice, whether on DO or DON'T are welcome. Additional background that may help, more than half of my catalogue images are wildlife/nature, mainly birding or macro. Other favoured genres are portraits, sport, and table top. I've flirted with street but struggle with landscape.