Focal ratio: All lenses in this comparison have a focal ratio which becomes smaller the further you zoom in. The Tamron 70-300 starts at f4.5 at 70mm focal length and reduces its focal ratio to f4.8 from 88mm, f5.0 from 116mm, f5.3 from 144mm, f5.6 from 175mm, f6.0 from 217mm, and f6.3 from 268mm onwards. The F-Nikkor 70-300 is a bit brighter (1/3 of a stop at the long end), same with the Z-Nikkor 100-400. [0] Sealing: All three lenses in this comparison have a rubber grommet at the lens-mount plus further weather-sealing throughout the construction. [+] Aperture ring and other control elements: The focus ring on the Tamron 70-300 can be assigned in camera to operate the aperture, exposure compensation, or ISO sensitivity – or simply switched off. This is similar to the multi-function control ring on the Z-Nikkor 100-400 but there are no other control elements/buttons/switches. The F-Nikkor 70-300 has no aperture ring but sports two switches to control focus and VR mode. [+] Image stabilization: No, the Tamron 70-300 solely relies on the sensor based stabilization of Nikon’s full-frame Z-mount bodies. Both Nikkor lenses have optical stabilization (VR). [0] There are two types of lens hoods, a “hard” lens hood and a “soft” lens hood. The first type of lens hood covers the lens barrel from the front side with a hardened cover, also known as a “cold lens hood”. It is usually of a two-piece construction. This type of lens hoods, if fitted properly, can reduce the intensity of stray light. On the other hand, if the lens hood is not fitted properly, then stray light transmission through it can be increased, and this can decrease image quality. The second type of lens hood is a “soft lens hood”, which is often covered by a third, more flexible and softer material, with an integrated attachment ring. The soft lens hood, on the other hand, can reduce the intensity of stray light. When should I use a lens hood?

Size (diameter x length): 77 x 150mm (3.0 x 5.9in.) plus 67mm for the lens hood. The F-Nikkor 70-300 is 81 x 146mm + 78mm lens hood. Add 30mm for the FTZ adapter to use it on a Nikon Z camera. The Z-Nikkor 100-400 is 98 x 222mm + 65mm lens hood. All three lenses in this comparison extend when zoomed to their longest focal length: The Tamron 70-300 extends to a maximum total length (incl. lens hood) of 277mm, the F-Nikkor 70-300 to 310mm (incl. FTZ adapter), the Z-Nikkor 100-400 to 336mm. [+] At the long end a 100-400mm zoom offers 33% more reach/magnification than the Tamron 70-300. To get the same angle-of-view of 400mm focal length you need to crop 1.33x into an image shot at 300mm. This would result in a reduction of resolution from e.g. 45MP to around 25MP – which might still be enough for the intended purpose. Among 300mm-capable telephoto zoom lenses for full-frame mirrorless cameras (As of August, 2022: TAMRON) To make the 300mm telephoto focal length more fun and accessible, TAMRON focused intently on designing a telephoto zoom lens that's both small and lightweight. Turning the conventional concept of a telephoto lens on its head, the 70-300mm F4.5-6.3 is only 148mm (5.8 in) in length with a maximum diameter of 77mm and a weight of just 545g (19.2 oz). This gives users the freedom to concentrate fully on shooting without worrying about lens size or weight. In addition to those wishing to pursue real telephoto shooting for the first time, the lens is also recommended for people who use cameras that have built-in image stabilization because they can leave the tripod at home. Of special significance, when paired with the APS-C mirrorless cameras, this zoom adds additional telephoto reach and while remaining comfortable to handle. Users can enjoy shooting with even higher power telephoto effects at a maximum equivalent focal length of approximately 450mm 3. Always place your lens hood where it will be needed when you take your picture. That way it will cover any part of the lens that might be visible in the photograph. If your hood is completely fitted around the lens, you can get away with only a slight gap at the nose of the hood itself, which you can cover with your hand or a small object. If not, you can use a little cleaning cloth or something similar to cover that gap to ensure that the lens hood does not disturb the image in any way. Properly placed lens hoods make your pictures look clearer, with less vignetting and fringing and depth of field Which lens hoods are best? ConclusionLens performance differs depending upon directions. Solid lines show performance in the sagittal (radial) direction while dotted lines indicate performance in the meridional (circumferential) direction. When sharp lenses capable of delivering uniform optical performance over the entire image field are tested, MTF charts show curves plotted in good balance. In October 2020 Tamron introduced the 70-300mm f4.5-6.3 Di III RXD (model A047) for the Sony E-mount. Now this 4.3x zoom becomes Tamron’s first lens for the Nikon Z-mount – and it’s currently the only lens for Z-mount with this zoom range. Nikon is clearly adopting a two-pronged approach with respect to licensing: for some lenses, Nikon’s decided to build or brand their own versions of Tamron’s optical designs (for example, the Z 18-28mm f2.8, Z 28-75mm f2.8, Z 70-180 f2.8), while the 70-300mm here is clearly a Tamron-branded model and more are likely to follow. This is good news as the portfolio of autofocus lenses for Nikon Z-mount is sure to expand even further and offer more choices for photographers using Nikon mirrorless cameras.

Above: Nikon Z 100-400mm f4.5-5.6 VR S coverage on a full-frame camera at 100mm (left) and 400mm (right) All lenses in this comparison cover full frame sensors or can equally be used on a cropped APS-C/DX camera body. [+] Use with teleconverters: No, neither the Tamron nor the F-Nikkor can be used with Nikon teleconverters. Only the Z-Nikkor 100-400 can use Nikon’s Z TC-1.4x and Z TC-2.0x. [0] Indicators/display: The Tamron 70-300 does not feature a distance or dof indicator on the focus ring like the F-Nikkor. The Z-Nikkor 100-400 has an OLED display indicating focal length, aperture, or focusing distance (in m or ft.) and depth-of-field. [0] To test the effectiveness of the image stabilization with the Tamron 70-300mm f4.5-6.3 Di III on a Nikon Z 7 camera body, I did a series of 140 test-shots hand-held at 300mm focal length with shutter speeds from 1/320 of a second down to 1/10 sec. I used the shots at 1/320 sec with VR=off as reference of how good my handholding was at the time of the test and Reikan FoCal did the chore of evaluating the sharpness of all shots.Autofocus: All lenses in this comparison offer autofocus with built-in focus drive. Manual-focus override is by simply turning the dedicated focus ring. On the Tamron 70-300 the focus ring turns the way Nikon users are used to and it has the non-linear gearing which most lenses for mirrorless cameras offer. But although the lens has a USB-C port to connect via computer to Tamron’s lens Utility (TLU) you cannot switch between variable or linear gearing nor can the direction of the ring be reversed – as you can do with the Z-Nikkor 100-400. Focus on the F-Nikkor 70-300 works differently as it has a direct linear mechanical coupling between the focus ring and the focus action. [+] The purpose of a lens hood is to prevent incident light from the side from being reflected by lenses or mount parts and thus reaching the image sensor or film or even the eyepiece. This stray light can lead to considerable impairment of the image, for example through optical overlaps in the form of light fringes in the shape of the lenses, i.e. usually circles or rings – the so-called lens flares. Furthermore, the image of the photographed or observed object becomes dull and low in contrast due to stray light. Why is stray light a problem? The Tamron 70-300 comes without a pouch or tripod mount but the reversible lens hood is included. Both Nikkors come with a pouch, the Z-Nikkor also has a tripod foot. [0] If you shoot with telephoto lenses, for example when photographing people or birds, the case is slightly different. With these lenses, light is scattered during the zooming so as to put the rays of light from the front of the subject onto the image sensor or film. In contrast, these same rays of light do not scatter when the lens is aimed straight ahead. This means that stray light from the front of the subject cannot be reflected in the image, thus reducing the amount of incident light from the front of the subject on the image sensor or film. Consequently, the pattern of stray light from the front of the subject is seen through the aperture blades of the lens and the resulting photographic image is more sharp. How often should I use a lens hood? How do I use a lens hood?

Let’s compare the new Tamron 70-300mm f4.5-6.3 Di III (“Tamron 70-300” for short) to theNikon Z 100-400mm f4.5-5.6 VR S (“Z-Nikkor 100-400”) and Nikon AF-P 70-300mm f4.5-5.6E ED VR (“F-Nikkor 70-300”) which was introduced in 2015 and still can be used via FTZ adapter on Nikon’s Z cameras. As usual I’ve rated the features with a [+] (or [++]), when it’s better than average or even state of the art, a [0] if it’s standard or just average, and [-] if there’s a disadvantage.Price: The Tamron 70-300 costs 660 EUR (incl. 19% VAT) / 700 USD / 660 GBP. The F-Nikkor 70-300 currently sells for 600 EUR / 600 USD / 630 GBP, the Z-Nikkor 100-400 is much more expensive 3000 EUR / 2700 USD / 2600 GBP. [+] Weight: At 577g (1.3 lb.) plus 62g for the lens hood the Tamron 70-300 is almost 100g lighter than the F-Nikkor 70-300 even before accounting for the 133g of the FTZ adapter you’ll need for the F-Nikkor. The Z-Nikkor 100-400 is much heavier at 1355g + 63g lens hood + 82g tripod foot. [+]

Focus accuracy and repeatability is critical to consistently produce sharp shots. Repeatability (the accuracy of focus on the same subject after repeated focus-acquisition) of the Tamron 70-300mm f4.5-6.3 Di III is very good (measured 98.7% in Reikan FoCal) with no outliers over a series of 40 shots. The lens focuses in around 0.5 sec from infinity at 200mm focal length to 2.17m (1:10 magnification), which is similar to the Z-Nikkor 100-400 but a bit slower than the F-Nikkor 70-300 (on a D810). MTF (Modulation Transfer Function) curves describe to what extent the tested lens can faithfully reproduce contrast of the subject in images it captures.

This small focus error probably is not relevant when shooting video, but when shooting stills it’s best to re-focus after changing the focal length. Minimum object distance is 0.67m (2.2ft.) with a magnification of 1:7.4 and a working distance of 0.50m at 70mm focal length. At 300mm focal length maximum magnification is 1:4.6 which is not bad and results in a working distance of 1.2m. A magnification of 1:10 is achieved at 3.06m. The F-Nikkor 70-300 achieves 1:3.8 at 300mm focal length and 0.97m working distance. The Z-Nikkor 100-400 achieve its maximum magnification of 1:2.5 at 400mm focal length and 0.68m working distance. [0]