Tamron 70-300mm f/4.5-6.3 Lens Review

bythom tamron 70-300mm.jpg

What is It?

The Tamron 70-300mm f/4.5-6.3 is the first autofocus Z-mount lens released by one of primary Japanese third-party lens vendors. Interestingly, Tamron has Sony as their majority shareholder (this has typically ranged between 20-25% of the stock). I write "interestingly" because it was it was almost six years before Tamron introduced a Sony FE-mount lens after the initial Sony Alpha full frame mirrorless cameras appears, while here it is just four years after Nikon’s entrance. Tamron has made their move faster with the Z mount than the FE mount. 

A version of this Tamron lens first appeared for the FE-mount in 2020 (originally US$549). I write "a version" because my brief testing with that lens on the Sony cameras produces somewhat different results than I got with the Nikon version. While the optical formula doesn't seem to have changed, I wonder if there's been an adjustment of something else in the Nikon Z-mount version. It could also be the difference in how Nikon does UVIR filtering (thinner stack) and manages microlenses on the image sensor. 

The optical design is 15 elements in 10 groups, with an unspecified number of low dispersion elements. The lack of image stabilization and special elements probably are what contribute to the low price of the lens. Tamron claims BBAR coating, though it's unclear where this is applied to the lens.

Apertures range from f/4.5 to f/22 at 70mm, from f/6.3 to f/32 at 300mm. The progression in maximum aperture goes something like this:

  • 70mm — f/4.5
  • 85mm — f/4.8
  • 110mm — f/5
  • 140mm — f/5.3
  • 180mm — f/5.6
  • 205mm — f/6
  • 260mm — f/6.3

The aperture diaphragm is a simpler 7-blade one.

Focus is performed using Tamron's usual RXD motor, a rapid stepper motor, which is essentially silent (seems a bit quieter than Nikon's stepper motors). Closest focus varies with focal length, with 70mm focusing to just under three feet (0.8m) and 300mm being just under five feet (1.5m). Maximum magnification is a disappointing 1:9.4 at 70mm, but a more reasonable 1:5.1 at 300mm. This is not a close focusing lens, by any measurement, but the 300mm end has a more normal, expected close focus distance. The lens supports M/A mode (e.g. manual focus override), as well as all of Nikon's autofocus modes. 

Overall, the lens is 5.9" in length (150.3mm) when collapsed. When zoomed to 300mm, the lens extends to almost 8.5" (210mm). The barrel extension is done via a typical inner sleeve. Unlike many such extensions, I see no play or wobble in the extension on my sample. While the lens is 77mm (3") overall in maximum diameter, the up-front filter ring is Tamron's usual 67mm (and doesn't rotate on zoom or focus). This means that if you pick up any of the Nikkor-labeled Tamron f/2.8 zooms (17-28mm, 28-75mm, 70-180mm) and this lens, you can get by with one 67mm filter set.

The lens is a scant 20.5 ounces (580g), which is light for a significant telephoto zoom. A lot of that is thanks to Tamron's choices of materials, though the lens does have a metal lens mount ring. The lack of extra controls also probably contributes to the light weight, too.

While the Tamron 70-300mm f/4.5-6.3 has no additional controls, it does feature a USB-C port for using Tamron's Lens Utility software, all in-camera lens corrections are supported, and you get an HA047 bayonet-type lens hood with the lens. Other than the wider mount area, the Z-mount version of the lens looks pretty much the same as the Sony FE-mount one. Tamron claims moisture-resistant construction, as well. 

The Tamron 70-300mm f/4.5-6.3 is made in China, and sells for US$699 in the Z-mount. 

Tamron's Web page for the lens

Source of the reviewed lens: purchased

How's it Handle?

There's not much to write about, as the lens has basically only two controls, the focus ring and the zoom ring.

The zoom ring is marked at 70, 100, 135, 200, and 300mm, and rotates through those focal lengths in less than a quarter turn. While the zoom ring on my sample was mostly smooth in rotation, it was a bit stiff through most of the rotation with a somewhat free-er turn from 200 to 300mm. The zoom ring is wide, easily found, and at the natural point where you'd be supporting the lens.

The focus ring is slightly stiffer than Nikon's versions, but still quite smooth. I would have preferred a deeper and bolder set of grooves on that ring, as when I try to move focus using my usual ring finger flick (due to supporting the lens with my palm), I can't get enough grip on the ring.

How's it Perform?

FocusI can’t say that I saw anything useful to write about in terms of focus performance. The lens focused quickly and reliably in my testing. It seemed up to handling birds in flight on my Z6 II. 

Sharpness: Central performance is excellent at f/4.5 at 70mm, and declines slightly until diffraction begins to be the primary contributor. Corners, however, are a different story. I'd judge them as poor wide open and you really have to stop down two stops before they become acceptable. They don't hit very good until f/11, where you start dealing with diffraction on most of the Nikon cameras. This corner performance appears to be mostly due to field curvature, so you might not always see it, but it absolutely will show up on flat subjects, such as test charts ;~). There's some spherical aberration, too, but it's not the primary contributor to corner fuzziness. f/8 is very good to excellent from the center to just beyond the DX frame, and the corners, while soft, start to become usable. 100mm and 135mm also show much the same pattern.

At 200mm, however, things change. The lens is suddenly very good from center to corner at f/8 (a bit less sharpness in the corners versus center, but not enough to change my wording). Moreover, the lens stays very good through f/16. Technically, f/11 is the "best" test chart result, but I'd say use the lens at f/8 to get the best compromise of results and sharpness. 300mm is much like 200mm, though not quite as sharp in the corners. At f/11 the center is excellent and the corners very good. 

The above was at closer "test chart" type of distances. I was actually expecting more of a change at long distance than I got. Again, at 70mm, the lens shows field curvature in the corners, though less than at close distance. The DX corners are a solid good at f/5.6, and improve again at f/8, where the extreme corners start to get into the good category. If there's a difference at the longer distances, it comes in the 100mm and 135mm focal lengths, where the corners snap into place faster. F/5.6 corners are actually in my good category at 100mm, and f/8 adds some additional contrast.

As with closer distances, the center declines slightly from excellent to very good+ at 200mm, and the corners are much closer to the center to the point where this lens is quite usable as a long distance landscape lens. At 300mm, the corners fall off a bit more, but I'd judge them to still be in the fair+ to good- range.

These results are a bit "old school" optical design, and not quite the far crisper results across the frame we've seen from the S-line Nikkors. But this is also a budget telephoto lens (particularly compared to the 70-200mm f/2.8 VR S). The Tamron 70-300mm f/4.5-6.3 is overall good but not great when it comes to MTF and contrast, whether it be overall or fine line. However, watch those corners in the wider end of the focal range, particularly as your focus distance comes closer to you. That’s probably the worst attribute of the lens.

Many of you have asked me to compare the Tamron to the Nikkor 70-300mm f/4.5-5.6E AF-P used on an FTZ adapter. I’d say the Nikkor is stronger in performance from 70-135mm, the Tamron stronger from 200-300mm. Most of you will want to opt for the Tamron if you don’t already have the AF-P Nikkor. If you have the AF-P, I’d say there’s not a strong incentive to switch, though someone always using the lens at 300mm would probably prefer the Tamron.

Chromatic Aberration: Surprisingly a bit of longitudinal CA wide open (not usual with a slow variable aperture zoom), though nothing that I'd worry about in normal results (it does show up in bokeh). Lateral CA seems reasonably well corrected up to 100mm, but with between one and two pixel's worth of impact at longer focal lengths on the Z7 II that's easily corrected.

Linear Distortion: 70mm is nearly linear and does not need correction. However, highly visible pincushion distortion (2%+) begins to show up at 100mm and peaks at 200mm (3%+). 

Vignetting: At 70mm, strong clipped corner vignetting of about two stops at f/4.5 that improves to my usual level of ignorability by f/8 and is visually undetectable by f/11. By “clipped” I mean that there’s a large central area mostly free of vignetting, but you see a distinct image circle when you look at the full frame. The “good” image circle area extends almost to the left and right frame boundaries (long axis), but not quite. 

Vignetting improves as you zoom in, a somewhat typical result with most telephoto zooms. At 300mm, the corner clipping is down to just over a stop wide open, and visually undetectable at f/9. 

Flare: The lens is not particularly prone to flare with frame-edge light sources, but it can absolutely show up with fully in-frame light sources, and consists of small, colored ghosts and a dip in overall contrast. This problem increases with focal length, and surprisingly, with smaller and smaller apertures.

If I’m interpretting the results correctly, there’s a bit more back flare (light bouncing off the filter over the image sensor, hitting the back element, and reflecting back into the image sensor) than I’ve seen on other telephoto lenses. 

Bokeh: Some minor onion rings, but one issue for many will be the bright ring that tends to pick up longitudinal chromatic aberration coloring wide open (magenta forward, green back). The bigger issue, however, is both cats eye and cutoff as you move out towards the corners. Round circles become quite strange-looking and inconsistent in the extreme corners, particularly at f/4.5 through f/5.6. That said, this lens is short and slow enough that you're not often reducing distant backgrounds to small blur balls. It's probably better to just assess the focal plane to blur transition, which you'll most often see at f/4.5 and 300mm. There I'd say that the lens is not at all dissatisfying. A slight bit on the "busy" side, but not the objectionable busy you may have seen with the old Nikon 70-300mm AF-P lens with its VR engaged.

Here’s an image from the lens at its best focal length under very tough conditions:

A complete lack of anything to complain about. Let’s look at it at 100%:

The background blur is very nicely rendered and un-busy. Foreground sharpness is very good (the grass here is slightly in behind the focus plane). I’m pretty happy with this type of rendering. 

Final Words

Yes, the Tamron 70-300mm f/4.5-6.3 is a bit of a conundrum. It's reasonably priced compared to the S-line Nikkors, but that also means it doesn't deliver the same level of optical performance. At the same time, this Tamron fills a gap in Nikon's telephoto lineup, where your other choices are the 70-200mm f/2.8 VR S or the 100-400mm f/4-5.6 VR S, both of which are considerably more expensive and heavier. 

There's another conundrum hidden in the lens, though, and that shows up most with DX cameras. While the 70-300mm f/4.5-6.3 performs quite well optically on the Nikon DX cameras, the lens doesn't have image stabilization, and the current DX bodies don't have sensor-based VR, as do the FX bodies. 450mm equivalent is tough to hold steady, so you'll want to opt for very fast shutter speeds on DX bodies. But the maximum aperture is f/6.3 when you’re using this lens for reach, so you're fighting a number of key factors simultaneously on the DX bodies. If your usual shutter speed is up above 1/1000, it's definitely a lens to consider for the Z50, but remember that your viewfinder won't be stabilized, and you’ll be at f/6.3, so may have to boost ISO. However, this brings up the Nikon 70-300mm f/4.5-5.6E AF-P VR again, as it does have built-in VR that would work with the DX bodies.

Which brings me to this: the camera this lens best aligns with is the Nikon Z5: you're picking affordability for some sacrifices in capability. A Z5 with the Nikon 24-70mm f/4 S and the Tamron 70-300mm f/4.5-6.3 provides a solid 24-300mm range in two lenses that are easy to travel with. You're weakest at the 100-135mm focal range, but perfectly fine from 24-70mm and 200-300mm. 

I like that we have this new travel friendly option. But it probably isn't for everyone. Thus, I'm not going to put a blanket recommendation on it. If you were happy with the F-mount 70-300mm choices, you'll probably be happy with this one on an FX body.

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