Really enjoy this adapter on my Sony APS-C camera for shooting old Nikon glass. It adds a stop of light and eliminates the crop factor when using a full frame Nikon lens.

Viltrox is not properly explaining the purpose of this adapter, which is a speed booster. The other reviewer is trying to use this adapter in a way it's not designed to work.

Those lenses that he mentions are intended to be used on DX (APS-C) sensor Nikons. Of course they will vignette when used with a speed booster. They already cover the APS-C sensor within their image circle and do not need the optical elements to reduce the size of the image circle to
more closely match the APS-C sensor. The reduction factor makes the image circle too small to cover the APS-C sensor, thus the vignetting.

This adapter is used to reduce the image circle diameter of FULL FRAME Nikon lenses so that they work more efficiently on APS-C cameras. It's what is known as a focal reducer, long used by astrophotographers to reduce image scale and increase brightness with a given lens at the sensor focal plane. Using this adapter with a 50mm Nikon prime will yield an effective focal length of 35.5mm (it has a .71 reduction factor). This means that this Nikon full frame lens will work like a 35.5mm on the E mount camera, which is a usable normal focal length. Using a non-optical adapter (without the lenses visible in the product photo) will simply adapt the 50mm Nikon lens to the APS-C body, and it will still be a 50mm lens...too long for 'normal' shooting but ok for portrait work.

I have and use this adapter to use my collection of Nikon prime lenses on my A6000. It works perfectly and each lens picks up about a full f stop of aperture. My Nikon full frame wide angle primes work like wide angles on the APS-C body and while there is a slight image quality loss it's not significant. It closely matches my much more expensive Metabones speed booster. This Viltrox is much better than cheaper 'lens turbo' and other speed booster adapters.

He might be able to use a Nikon F to E adapter (without optics) as long as the adapter includes an aperture control ring, since many newer Nikon autofocus lenses don't have an aperture ring (beginning with the G lenses). However, even if the adapter allows adjustment of the aperture THE AUTOFOCUS AND POWER ZOOM functions will not work. Since many newer autofocus lenses aren't really designed for manual focusing this is hardly a good idea. Even if it works it'll feel like you're focusing a junk plastic toy lens, since the mechanism is designed to be operated by a low power motor or actuator...they had to make the moving parts as light and flimsy as possible.

The way that this vignettes is vey weird. I am using a crop sensor camera so its ridiculous.
I am using Sony A6300.

On Nikon 10-24 It vignette starting at 10 and then it goes away till I zoom until 15mm
On Sigma 18-35 it vignettes starting at 18 and the it goes away when i zoom in until 23mm

It limits the range of my zoom lenses by a lot, it sucks.