Last Updated on May 7, 2023 by Photography PX
The 24-70mm focal length is a long-standing go-to lens, and the jack of all trades range in a photographer’s arsenal. With this focal length alone, photographers can shoot anything from wide-angle landscapes to medium telephoto portraits or macro photography. And for that reason, it’s often the first go-to lens for the level of versatility it offers to meet the demands of virtually every situation.
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The 28-75mm Di III RXD lens is the result of Tamron’s bold ambition to pack cutting-edge technology into a compact, high-speed zoom lens, ideally suited to match the mirrorless digital camera ideal.
Initially released in the summer of 2018, this is their first lens specifically designed for use with Sony mirrorless ecosystem. And, of the lenses they’ve released to date, this is arguably their most critical release thus far. This lens aims to compete directly with the first-party competition, most notably the Zeiss 24-70 f/4. Considering this is Tamron’s first attempt at Sony mirrorless, can they succeed at such a grand ambition? Today, we will assess its strengths, weaknesses, and answer whether or not this lens can tackle the mirrorless giant.
What are the designations that Tamron uses?
What is Di?
The first designation is Di, which stands for Digitally Integrated design. This term represents a generation of lenses that Tamron designed for use with a specific subset of cameras. In this case, Di III represents their lineup of lenses designed and engineered specifically for use with mirrorless cameras.
What is RXD?
The second designation is RXD, which means Rapid eXtra-silent stepping Drive, which is a newly developed autofocusing motor designed for mirrorless cameras. Essentially, RXD uses a stepping motor to drive focusing without gears or vibrations to deliver accurate focusing that’s completely silent during motion. And it also uses a sensor that determines the lens’s current focus setting for added precision and speed. Overall, this type of configuration makes these lenses ideally suited for focusing on moving subjects and capturing video. At this time, Tamron currently holds two RXD lenses, one of which is the 17-28mm f /2.8.
What mounts does this lens support?
Tamron specifically designed this lens to maximize the potential of Sony E-mount mirrorless cameras, be they full-frame and APS-C formats. Since this lens was designed from the ground up for use with this platform, it can also fully take advantage of all software-based technologies offered in Sony cameras.
Build Quality, Construction, and Design
Some general specifications, this lens opens to f/2.8 and closes to f/22, which is an incredibly strong range. It uses the 67mm filter thread and weighs 1.2 lbs or 550 g. One of the most advertised and strongest highlights of this particular lens is its Minimum Object Distance, which Tamron calls MOD. In addition to shooting anything from portraits to landscapes, this lens also shines for close-up macro work, opening a new world of possibilities, particularly at the wide-angle end. Unlike the competition, this lens doesn’t suffer from a fixed MOD throughout its entire focal range.
Instead, at 28mm, it provides a MOD of 0.19m or 7.5 inches. In this setting, it also provides a working distance of 5.7cm (2.24 in) from the front element for incredibly close-up shots, which gives an interesting sense of perspective unique to wide-angle lenses. While at 75mm, it delivers a MOD of 0.39m or 15.3 in, which provides close-up images that easily rival a comparable macro lens.
Internally, the optical construction combines 15 elements into 12 groups. Two of which are Low Dispersion elements to combat chromatic aberration and color fringing, and three aspherical elements to minimize distortion. Tamron also uses a nine-blade circular diaphragm, which produces beautiful round defocusing bokeh. It also features 6 leak-resistant seals throughout the lens barrel, providing a moisture-resistant construction and added protection. While not to the same level as the G Master, it does offer better protection than Sony’s own FE 28-70. Nevertheless, build quality and construction remain excellent.
Tamron has also treated the front element with their proprietary BBAR coating, which dramatically reduces unwanted flare and ghosting. It does this by suppressing the reflections that otherwise occur, thus maintaining contrast and detail. They’ve also coated the front element with a fluorine compound that is both water and oil-repellent. This fluorine coating makes the lens easier to clean and less vulnerable to the damage caused by dirt, dust, and moisture.
For the autofocus, the lens uses the all-new precision AF drive system with the RXD motor. This combination delivers silent autofocusing and uses a sensor that detects the current position of the lens for added precision. This system makes the lens ideal for shooting moving subjects and recording video, as it’s both smooth and quiet. Gone are the days of worrying about picking up background noise caused by a drive motor as the lens autofocuses.
At this point, the lens uses the camera as an interface for updating the firmware. This occurs through a downloadable software from Tamron’s support page, and this process is straightforward and intuitive.
The images this lens produces are gorgeous. And image quality remains sharp wide-open throughout the entire zoom range, with a soft and smooth bokeh rendering. 28-75mm is also an excellent overall range, providing ample versatility from shooting wide-angle street or landscape to portraits and macro photography. At 75mm, the lens also offers a reasonable working distance and an impressive 1:4 reproduction ratio, or 1:3 at 28mm.
However, you do have to get significantly closer to take advantage of that magnification. With this type of flexible working distance and zoom range, the lens is supremely suited as an ideal all-rounder for those without the budget for additional lenses. Overall, the lens performs admirably, with little, if any, chromatic aberrations and is free of noticeable tints.
However, there are a few things to note on performance. Firstly, this lens does suffer from barrel distortion at 28mm, which is particularly problematic when shooting video if you have older Sony cameras without the profile to correct it in-camera. Barrel distortion is a type of distortion that causes parallel or straight lines to slightly curve inwards. While it is possible to fix this type of distortion in post during videos, it’s quite challenging.
If you plan on shooting video with this lens, do bear this in mind. Secondly, the lens does have quite a noticeable vignette when shot wide open, but this is easy to fix in post, so it isn’t anything substantial. But more importantly, the lens delivers average performance when it comes to ghosting and flares if shooting in backlit conditions, a problem-plagued by most zoom lenses to be fair.
Tamron has installed low dispersion elements to minimize its effect, but they remain present. If you shoot in backlit conditions often, take caution as the ghosting can potentially ruin your shot.
Autofocusing performance is excellent, precise, and fast. We tested this lens in combination with the Sony a7. And, while its focusing system is archaic compared to more recent iterations, the combination delivered an incredible performance. The RXD drive motor installed on the lens also delivers entirely silent autofocusing. So, users can rest assured knowing that there won’t be any microphone pickup under any circumstance.
For video specifically, know this lens is parfocal. Parfocal means it maintains focus even while zooming, and it’s a must feature for using a lens for video. However, the lens does have a small amount of focus breathing, where objects enlarge as the lens approaches the minimum focusing distance. But, this is acceptable considering this is primarily a stills lens and not a video lens.
As this lens is designed for Sony E-mount mirrorless cameras, it also supports the full gamut of advanced features they offer. These include hybrid AF, Real-time tracking, Eye AF, DMF, and any in-camera lens correction supported. It’s impressive to see such cross-compatibility provided by a third-party manufacturer, as this typically isn’t the case.
The focusing collar works quite well for both photos and videos. It uses a focus by wire system, which is a direct connection to the camera that requires the camera to send signals to the focus motor to change distance. Thankfully, this system is linear. However, it does have a small amount of latency that takes some familiarization to master. And while this is not the preferred method for manual focusing, as it doesn’t allow for pre-focusing when the camera’s off, the focusing it provides remains excellent.
Lastly, comparing the Bokeh rendering. When compared to other Sony lenses, the bokeh displays more of an artistic appeal, similar to a vintage lens that swirls slightly. And for some, you may dislike this particular rendering depending on your taste. For us, this wasn’t an issue.
In the end, this lens strikes a beautiful balance between performance and size. And Tamron has executed the design well. Its compact size and lighter weight provide a distinct edge in its favor compared to the competition. While some reviewers and journalists may claim it feels on the cheaper side, this is not the case. Tamron has tailored the construction and design of this lens towards the traditional mirrorless ideal. That ideal, in of itself, is to remain compact, yet capable. The fact that it’s lightweight and still provides this level of performance makes it a far more compelling option. It’s especially a good option for those who frequently travel or want added discretion when shooting.
The only minor limitation is its focal length does reach 24mm. This extra 4mm could be a potential drawback to users who like to shoot ultra-wide angles that don’t have an equivalent lens at this focal length already. The reality is that sometimes moving back further isn’t always an option. In those situations, the extra length on the wide end does become beneficial. However, considering the added bulk and weight involved with designing a 24mm f/2.8 lens, this trade-off for the minor inconvenience is worthwhile.
In value, it also provides a far better proposition for those who lack the budget for Sony’s flagship 24-70 GM lens. Under normal circumstances, this lens delivers largely identical autofocusing speed, sharpness in the center of the frame, and less chromatic aberrations at the edges. For this reason, it makes for an excellent budget-friendly option for those looking for a zoom lens in this range. It’s only real drawbacks in comparison to the GM are the lack of a manual focusing toggle and the missing focus hold button. Many reviewers have compared this lens directly to the 24-70 GM, but truthfully this isn’t a fair comparison.
Sure, they both deliver 2.8 apertures with broadly similar focal lengths. However, the Sony GM lens is in another league. And this is not the league Tamron aims to compete specifically with this lens. This comparison would be more plausible if this were an SP 24-70mm entry in their lineup, but it’s not. And the truth is Tamron has done extraordinarily well to create an excellent all-in-one traveling companion or hybrid shooter that dominates the competition. And it is undoubtedly one that will remain relevant for years to come.
In the end, the Tamron 28-75mm is an extraordinary release by the manufacturer. Tamron has once again shown their prowess and engineering capabilities. This lens also proves that they’re competitive in both DSLR and mirrorless domains as well. There’s no questioning why this lens is so popular. It’s easily one of the best lenses you can get for the Sony E-Mount platform.