Verdict

As Tamron’s first branded lens with Nikon Z-mount the 70-300mm f4.5-6.3 Di III will certainly garner quite some attention: It covers a 4.3x zoom range which is not yet available in Nikon’s line-up of Z-Nikkors and nicely complements any 24-70mm or 28-75mm standard zoom. In addition the lens is affordable, light, and relatively small. It also has a customizable focus/function ring, is thoroughly sealed against the elements, and can reach magnifications of 1:4.6 at a very usable working distance. Note the design is optically the same as the earlier version for Sony e-mount, so my optical results apply for anyone buying that version too.

In my tests it turned out to be a good all-round performer: contrast and resolution across the full zoom range and the DX image-circle, focus speed and reliability are all on a high level with colour aberrations, coma, and focus-breathing absent or at least very well controlled. And the IBIS of any full-frame Z camera body proved to be very effective even at 300mm giving the lens a 4 stop boost in handhold-ability – which is a real boon when shooting the lens at the long end.

What’s not to like? Well, the most severe issue in my opinion is field curvature at 70mm. It makes the FX-corner look soft at long distances, doesn’t respond well to stopping down, and becomes stronger the closer you focus: At minimum object distance it starts affecting sharpness already a few mm off center. Smaller issues are the dampening of flare and glare which could be better and that the lens is not perfectly parfocal – so it’s important to re-focus after changing focal length. Regarding features: My biggest gripe is with the lack of optical image stabilization although the built-in stabilization on Nikon’s full-frame Z cameras does a great job. But when you are using the lens on one of Nikon’s DX bodies you’ll sorely miss image stabilization when you want to shoot handheld at 450mm equivalent focal length. Another small issue is that Tamron’s lens utility can only update the firmware of the lens and does not offer more options for customization as with other Tamron lenses compatible with their utility.

Let’s put this into perspective and have a closer look at how the Tamron 70-300mm f4.5-6.3 Di III compares to its F-mount alternative, the Nikon AF-P 70-300mm f4.5-5.6E ED VR, and the Nikon Z 100-400mm f4.5-5.6 VR S.

Above from left to right: Nikon Z 100-400mm f4.5-5.6 VR S, Tamron 70-300mm f4.5-6.3 Di III, Nikon Z 70-200mm f2.8 VR S

Compared to Nikon AF-P 70-300mm f4.5-5.6E ED VR

In 2017 Nikon managed to release their best 70-300mm F-Nikkor to date and the lens deservedly earned high praise. My current test of the Tamron 70-300mm reminded me in many cases of the F-Nikkor: Although I had tested the latter on a 36Mp D810 the optical qualities of both lenses seem to be pretty close with the F-Nikkor showing much less field curvature. So if you already own the AF-P 70-300mm f4.5-5.6E ED VR you can continue to use it via FTZ adapter on a mirrorless Nikon Z body with good results. Especially if you plan to use it on a non-stabilized cropped Z camera: You’d sorely miss image stabilization when using the Tamron 70-300mm f4.5-6.3 Di III handheld.

For more details see my Nikon AF-P 70-300mm f4.5-5.6E ED VR review where it earned a Highly Recommended in 2017.

Compared to Nikon Z 100-400mm f4.5-5.6 VR S

If you’re looking for a telephoto zoom lens which covers the full-frame sensor and reaches beyond 200mm focal length from Nikon their Z 100-400mm f4.5-5.6 VR S is the only available Z-Nikkor. It’s bigger, more than twice as heavy and costs four times as much as the Tamron 70-300. But it produces very sharp images with almost no field-curvature or colour aberrations and is able to reach 1:2.5 magnification. It also offers optical image stabilization which delivers over 5 stops of stabilizing power on a full-frame Nikon Z camera and should be a boon when using the lens on a cropped non-stabilized Z body. It starts only at 100mm on the wide end, so leaves a substantial gap when combined with a standard zoom reaching 70mm or 75mm. But then it goes up to 400mm at the long end and works well with Z teleconverters should you need even more reach.

For more details see my Nikon Z 100-400mm f4.5-5.6 VR S review where the lens came Highly Recommended.

Tamron 70-300mm f4.5-6.3 Di III final verdict

The 70-300mm f4.5-6.3 Di III is a worthy first lens from Tamron with Nikon’s Z-mount. It fills a gap in Nikon’s line-up of Z-Nikkors and is affordable, light, and pretty well equipped with a customizable focus/function ring, thorough weather sealing, and a maximum magnifications of 1:4.6 at a very good working distance. It produces sharp to very sharp images at all focal lengths across the full frame – except at 70mm where corner performance is severely hampered by field-curvature. AF is fast and reliable and even Bokeh is quite nice for an f4.5-6.3 lens. Only the missing optical image stabilization makes the lens not the best choice for Nikon’s non-stabilized cropped sensor cameras. But other than that Tamron’s 70-300mm f4.5-6.3 Di III clearly earns a Recommendation. My optical results also apply to the earlier version of this lens for Sony e-mount cameras.

Good points:

• Good to very good resolution and contrast at all focal lengths across the full frame (except at 70mm).
• Usable close-up performance at 300mm focal length.
• Almost no longitudinal colour aberrations or purple fringing.
• Fast and reliable AF operation and very low focus breathing.
• Nice (although not great) Bokeh.
• Weather sealing and multi function focus ring.
• Light weight and low price.

Bad points:

• No optical image stabilization.
• Strong field-curvature at the short end.
• Dampening of flare and glare could be better.
• Not perfectly parfocal.
• Tamron’s lens utility does not offer lens customizations, can only update firmware.
• No lens pouch.