Kenko TELEPLUS HD pro 1.4x DGX Teleconverter for Nikon F

Lens tested: Nikkor AF-P 70-300 4.5-5.6E D7500: Drastically reduced AF performance on the long end (slow focus acquisition, lens pulsates heavily) esp. when shifting focus on various distances. Focus lock quite sensitive, easily confused, shifted and dropped. My Workarounds: Set Group Area AF (both AF-S/AF-C) for improved AF performace, pulsating is still there but acceptable. Set the Camera Focus tracking with Lock-on to 5. Retract the lens, re-focus and zoom-in when I really struggle to lock focus.. Works well on bright days and high contrast subjects. Low light performance is inconsistent. Image quality is Good, better than expected. Z7 (w/ FTZadapter): Lens + TC won't work at all if mounted normally. Camera must be switched-on before Lens + TC is attached; thereafter, all functions are working. Try to avoid resetting the camera or letting it into sleep mode. AF-S/AF-C both work, although not as smooth, but way better experience than with that of D7500's (IMO). Tracking works too Good image quality as well. General: Build quality and finish is very good, matches the camera/lens exterior, and very compact, Quite unnoticeable when mounted. Hope that Kenko/Tokina are able to patch the mounting issue, this combination is quite promising with the Z series bodies Bought this TC for practice, while saving up for that longer telephoto lens. Did quite some advance reading as this is my first TC. Nikon and Kenko did warn of some issues, so those AF and IQ compromises were easier for me to swallow. Never had high hopes really, but quite surprised with its performance, especially with the image quality and when mounted on the Z7. I like it actually. (attached photos are SOC, screen cap from Fastone Image Viewer)

I bought this teleconverter planning to use it with my 70-300mm AF-P lenses, both DX and FX, on my D500 and Z7 (via the FTZ adapter). First and foremost, neither lens will autofocus at all using the FTZ. They register on the camera as manual focus lenses and focus-by-wire doesnt work. On the D500, the FX lens works in both AF-C and AF-S, but the teleconverter does not show up in AF fine tune, meaning the setting defaults to the adjustment set for the lens only. The lens will AF fairly quickly to *almost* in focus, and then it takes another second or two to lock, but this is only on high contrast subject matter in outdoor sunlight. Images appear to be correctly focused but lacking in acuity. With the 70-300mm DX lens, using AF-C generates a jumpy image in the viewfinder and the lens seldom finds focus. With AF-S, the jumpy image issue is less pronounced; and in good light on contrasting subject matter, fairly sharp images with decent acuity are produced whenever the camera is able to lock focus. Build quality of the teleconverter appears to be okay, and it isnt defective. Its unfortunate, though, that the people most likely to buy this item, long lens shooters, are the ones most likely to be disappointed with it.