Nikon introduced two new teleconverters with its professional Z 70-200mm f2.8 VR S telephoto zoom: The Z TC-1.4x and TC-2.0x teleconverters are designed for Nikon’s Z-series mirrorless cameras and corrected for full-frame sensors. Teleconverters are mounted between the lens and the camera body and magnify the image by 1.4x or 2.0x thus effectively increasing the focal length of each lens by the same amount. Unfortunately lenses have to be designed to work with teleconverters and currently the Nikon Z 70-200mm f2.8 VR S is the only lens which can be used with Nikon’s new TC-1.4x and TC-2.0x. But Nikon will certainly add more lenses to their Z line-up in the future which can use teleconverters.
Physically and optically teleconverters are pretty simple affairs: 6-8 lens elements in a sturdy short metal barrel with no moving parts, switches or controls. Still a good teleconverter is not a cheap affair: They are listed at 613 EUR (incl. 16% VAT) / 547 USD / 549 GBP for the TC-1.4x and 662 EUR / 597 USD / 599 GBP for the TC-2.0x. As you cannot judge the quality of a teleconverter on its own I tested both on the Nikon Z 70-200mm f2.8 VR S (which is an excellent lens) and compared image quality with and without the use of teleconverters. PS – if you’re interested in my in-depth review of Nikon’s professional tele-photo zoom lens I tested the teleconverters with have a look at my Nikon Z 70-200mm f2.8 VR S review.
Facts from the catalog
Let’s have a closer look at the features and functions of Nikon’s new Z teleconverters. As usual I’ve rated the features with a [+] (or [++]), when it’s better than average or even state of the art, a  if it’s standard or just average, and [-] if there’s a disadvantage. For comparison I use the the Nikon AF-S TC-14E III and AF-S TC-20E III (“F TCs” for short).
Size: The diameter of both TCs is 72mm (2.8 in.). The length is 19mm (0.7in.) resp. 33mm for the TC-1.4x and TC-2.0x – not counting the protrusion at the front which extends into the mounted lens. The F TCs are 64mm in diameter and 25mm resp. 46mm in length. 
Weight: 220g (7.8 oz.) for the TC-1.4x, 265g (9.4 oz.) for the TC-2.0x. Both TCs are massive affairs with fully metal bodies and no moving mechanical parts. The F TCs are 190g and 330g resp. 
Optics: 6 elements in 4 groups for the TC-1.4x, 8 elements in 5 groups for the TC-2.0x. Both teleconverters have one aspherical element and employ fluorine coating at the front and back. The F TCs have 7/4 and 7/5 elements/groups and also have fluorine coating (at least the F TC-14E III). [+]
Closest focus distance and maximum magnification: The closest focus distance of the lens attached to a teleconverter does not change – except for the length of the TC. Maximum magnification is multiplied by the factor of the teleconverter. So if you use the Nikon Z 70-200mm f2.8 VR S on a TC-1.4x you get a maximum magnification of 1:3.3, with a TC-2.0x the lens achieves 1:2.4. These are very good magnifications and the TCs don’t change the working distance: still a very good 0.72m. And the lens still focusses to infinity, something you cannot achieve with a close-up filter like the Canon 500D. The same holds true with the F TCs. [+]
Filter-thread: no need to buy new ones. The same filters still can be used at the front of the lens. Which in case of the Nikon Z 70-200mm f2.8 VR S are 77mm diameter. [+]
Image stabilization, auto focus, additional functions: Everything works as expected as the teleconverters don’t interfere with the functions and features of the attached lens. EXIF data for focal length and aperture are adapted and the identifier for the lens also reflects the use of TCs. Even the display of the Z 70-200mm f2.8 VR S shows the correct values for aperture and focal length. [+]
Focal ratio: Here’s the one and major disadvantage of teleconverters: TCs make your lens less bright. You lose one stop with the ZC-1.4x and two stops with the TC-2.0x. So the Nikon Z 70-200mm f2.8 VR S becomes a 98-280mm f4.0 lens on the TC-1.4x and a 140-400mm f5.6 lens on the TC-2.0x. [-]
Lens profile: Each Z-Nikkor comes with a lens profile for lateral color aberrations, vignette control, diffraction compensation and distortion control. The profiles still work when a TC is attached. [+]
The TCs principally work with lenses corrected for full-frame sensors or smaller. Unfortunately the Nikon teleconverters don’t work with every Z lens: only the Z 70-200mm f2.8 VR S can be used with TCs so far. 
Works with FTZ-adapter: NO, don’t try it! The protruding glass elements of the TCs will not fit into the FTZ-adapter and you may damage the optics. Would have been nice to use all F-mount lenses via FTZ-adapter on the new Z TCs – but no. [-]
Price: 613 EUR (incl. 16% VAT) / 547 USD / 549 GBP for the TC-1.4x and 662 EUR / 597 USD / 599 GBP for the TC-2.0x. This is a mark-up of roughly 20% over the prices of Nikon’s teleconverters for F-mount. 
The teleconverters come with a pouch that’s just as flimsy as the pouch of the Z lenses and has no strings to pull it close. 
Sealing: yes, a rubber grommet at both lens-mounts. [+]
The score in the “features-department” is 2[-]/5/6[+]. The biggest disadvantage when using teleconverters is the reduction in focal ratio by 1 stop for the TC-1.4x and 2 stops for the TC-2.0x. But that is the laws of optics at work – and not the fault of Nikon. The other [-] is the inability to use the new TCs in combination with the FTZ-adapter. Not sure how good the image quality would have been. But Nikon deliberately precluded this combination so we will never know. You may also not like the relatively high price compared to the street price of Nikon’s F-mount TCs. But if the optics are good the teleconverters are worth their money.
The best thing about the teleconverters is that they integrate transparently into the Z system with all the correct EXIF-data and that lens-profiles, image stabilization, auto-focus, etc. are working as expected.Check prices on the Nikon Z TC 1.4x at Amazon, B&H, Adorama or WEX! Check prices on the Nikon Z TC 2x at B&H, Adorama or WEX. Alternatively get yourself a copy of my In Camera book or treat me to a coffee! Thanks!
If you have F-mount teleconverters from Nikon you can still use them via FTZ-adapter on a Nikon Z camera body. But those naturally work only with F-mount lenses. If you want teleconverters for your Z-mount lenses there’s only Nikon’s Z TCs available. But if you want to use the Z teleconverters for your F-mount lenses, tough luck: the FTZ adapter does not fit on the Z TCs.
And in case you’re wondering if you need teleconverters at all: Here is the angle of view that the Nikon Z 70-200mm f2.8 VR S covers with its 2.9x zoom compared to the reach of the lens in combination with the Z TCs:
A pretty impressive difference! And if you’re wondering whether you can achieve the same results by simply cropping: Yes, you can. To achieve the same angle of view of the TC-2.0x you simply need to crop the image without TC by a factor of two. But then you’re losing 75% of pixels and end up with an 11MP photo instead of the original 45MP. Which might well be enough for the intended print or viewing size: a modern 4k Monitor only has 8MP and printing an 11MP photo at a very fine pixel-density of 240 dpi still yields a print of 17×11 in. or 44 x 29cm.
On the next page I compare the quality of an image shot with the TC-1.4x at 280mm cropped down to the angle of view of 400mm focal length with an image shot with the TC-2.0x at 400mm. Prepare to be surprised!
Next check out my quality results!Check prices on the Nikon Z TC 1.4x at Amazon, B&H, Adorama or WEX! Check prices on the Nikon Z TC 2x at B&H, Adorama or WEX. Alternatively get yourself a copy of my In Camera book or treat me to a coffee! Thanks!