This feature uses the resolution of the image sensor to 'zoom' the video in rather than needing to zoom the lens. It's smooth and works well for me. I really love this little gem they added (Z9 has it also).
I'll put my Z8 photos here: www.thephotographyhobbyist.com/CAMERAGEAR/Nikon-Z8-Gallery/ Also, regarding the conditions for Hi-Res Zoom to work, Nikon says... Hi-Res Zoom is available when all the following conditions are met: [FX] is selected for [Image area] > [Choose image area] in the video recording menu, [ProRes 422 HQ 10-bit (MOV)], [H.265 10-bit (MOV)], [H.265 8-bit (MOV)], or [H.264 8-bit (MP4)] is selected for [Video file type] in the video recording menu, and a frame size and rate of from [3840×2160; 30p] to [3840×2160; 24p] or from [1920×1080; 120p] to [1920×1080; 24p] is selected for [Frame size/frame rate] in the video recording menu. Also a few more caveats: - AF-area mode is fixed at [Wide-area AF (L)]. The focus point is not displayed. (this one confused me because I was wondering why I couldn't select the AF Area Mode (now I know why, need to turn off Hi-Res Zoom) - [Electronic VR] in the video recording menu is fixed at [OFF]. Nikon User Manual for Hi-Res Zoom: onlinemanual.nikonimglib.com/z8/en/hi_res_zoom_guid-8e678b69-ce7d-5442-a145-d7db8104b565_39.html
So, you'll notice you can't use it when shooting 4K 60p, which is a bummer...but pretty much all the 1080 frame rates are supported for hi-res zoom (120p down to 24p)
It's available in 4k but not 8k. The conditions/details are shown here: onlinemanual.nikonimglib.com/z8/en/hi_res_zoom_guid-8e678b69-ce7d-5442-a145-d7db8104b565_39.html
I had the 24-120 mounted in this case but I was not zooming the lens. It works with prime lenses also. The image sensor supports 8K resolution so I think what they do is if you're in 4K/30P for example, the camera is oversampling and using 6K or 8k, so when you start to 'zoom' in, it's really just cropping the video to zoom, BUT you're not losing resolution. If you shoot in 4K you'll still get 4K. Same for 1080. If you shoot in 1080 and use hi res zoom, you still get 1080. It's not degrading the video.
It doesn't work above 30p in 4K but it works from 24p up to 120p in 1080. I just confirmed on my own camera. Nikon info: onlinemanual.nikonimglib.com/z8/en/hi_res_zoom_guid-8e678b69-ce7d-5442-a145-d7db8104b565_39.html
