Thomas902 Loc: Washington DC

"...Nikon 70-300 AP DX VR..." Bob makes an interesting (and cost effective) inference here albeit it's build quality falls a tad short for serious commercial assignments. That said it has a special place in my kit as it's size/weight/image quality ratio is nothing short of amazing (even wide open!). However it's bigger sibling (the FX variant is far superior in virtually every aspect (even mounted on a DX body)).

Caveat: This is one DX lens I would never consider purchasing "Previously Owned" in that it is rather fragile. It has a plastic mount like the AF-P Nikkor 18-55mm f/3.5-5.6G ED VR. Both of these Nikkors are not likely to withstand much abuse, enough said.
Best to pony up for a new copy with a warranty.
https://www.bhphotovideo.com/c/product/1275036-REG/nikon_20062_afp_dx_nikkor_70_300mm.html

Ruby-throated Hummingbird (Archilochus colubris) AF-P Nikkor 70-300mm f/4.5-6.3G ED VR; 300mm; f/6.3; 1/1000

(Download)

FreddB Loc: PA - Delaware County

When I looked for one, none compatible with Nikon - have to check again.

CHG_CANON Loc: the Windy City

You can check again, the incompatibility has not changed.

There are two issues:

1. The Nikon versions literally 'extend' into the attached lens. The 18mm-to-whatever lenses don't have the necessary space inside the rear of the lens, at the mount point, to allow you to physically attach the extender / teleconverter to the target lens. Canon and Sony are similar in this design.

2. The variable aperture of these zoom lenses is such you'll lose autofocus, even if you could attach the extender. This is why 3rd party models that might attach (overcoming issue #1) will still not be a desired solution if the 1-stop or 2-stop change in effective aperture pushes the max aperture smaller than f/5.6, definitely when smaller than f/8 on any type DSLR.

Thomas902 Loc: Washington DC

"...The variable aperture of these zoom lenses is such you'll lose autofocus..."
Paul speaks with wisdom & authority here.

I noticed that my AF 70-210mm f/4-5.6D with a Kenko 1.4X Teleplus PRO 300 DGX will not AF on my D7200 or D3x while my epic AF 70-210mm f/4 has no problems with the Kendo 1.4 Tele Extender!

So yes an F-Stop can be a game changer.
Another issue that folks overlook is that a bright f/2.8 will "lock" focus instantly while an f/5.6 is sluggish (to say the least)... Once I immigrated to an AF 300mm f/2.8 my "hit" ratio tripled on League Soccer matches. Now only use my AF-S 200-500mm f/5.6E for causal Portraiture and Fashion Editorials... The AF 300mm f/2.8 rules for Sports Action!

Hope this helps... Thank you Paul for bringing clarity into the Main Photography Forum, far too many uncorroborated "options" clutter this space thus sometimes make it questionable at best...

If you're not shooting primes you are missing out on what is actually possible to achieve.
Experience is a brutal yet highly effective teacher...
Cheers! All the best moving forward into 2022 :)

FreddB Loc: PA - Delaware County

I did. You’re right.