In summary
Tamron’s 28-200mm f/2.8-5.6 Di III RXD is only available with the Sony FE mount so far but its combination of an affordable price, compact size, light weight and decent performance give it an advantage over its rivals. It’s one of the best convenience zoom lenses we’ve tested.
While there are the inevitable compromises in lens speed, especially at longer focal lengths, the ability to shoot at f/2.8 for focal lengths between 28mm and 31mm is exceptional in a lens of this type. So is its focusing distance range, which provides good flexibility in working distances for close-ups.
Full review
Announced in June, 2020, the new Tamron 28-200mm f/2.8-5.6 Di III RXD (Model A071) is a contemporary update to Tamron’s first all-in-one zoom lens, the AF 28-200mm f/3.8-5.6 Aspherical (Model 71D), which dates back to 1992. In acknowledgement, the new lens has adopted the ‘71’ designation of the original lens. All the technical capabilities and know-how amassed over the last 28 years have been included in the new 7.1x zoom lens, which has been designed exclusively for Sony’s full-frame mirrorless cameras.
The Tamron 28-200mm f/2.8-5.6 Di III RXD lens, shown without end caps and lens hood. (Source: Tamron.)
The optical design for this compact and lightweight lens consists of 18 elements in 14 groups and includes two glass-moulded aspherical, two hybrid aspherical, one XLD (extra low dispersion) and two low dispersion elements. A ‘BBAR’ (Broad-Band Anti-Reflection) coating reduces ghosting and flare, while the front element is fluorine coated to repel oil and water. A rounded seven-blade diaphragm contributes to a pleasing bokeh quality.
This diagram shows the positions of the exotic elements in the optical design. (Source: Tamron.)
Autofocusing is driven by a fast RXD (Rapid eXtra-silent stepping Drive) stepping motor and algorithms that can accurately detect the position of the focus group. The compact configuration of the RXD AF drive system contributes to the size and weight reduction in the lens. Manual-focus override is possible by rotating the focus ring in AF mode.
Although it lacks integral stabilisation, the 28-200mm f/2.8-5.6 lens is compatible with the in-body image stabilisation in Sony cameras. Other Sony camera features like Fast Hybrid AF and Eye AF are supported and focusing is quiet enough for it to be used in venues that require low noise levels as well as for video recording.
The aperture range is as wide at both ends of the scale as you’d expect in an extended-range zoom lens. The table below shows the maximum and minimum apertures at the marked focal length settings.
| Focal length | Maximum aperture | Minimum aperture |
| 28mm | f/2.8 | f/16 |
| 35mm | f/3.2 | f/18 |
| 50mm | f/3.5 | f/20 |
| 70mm | f/4.0 | f/22 |
| 100mm | f/4.5 | f/25 |
| 135mm | f/5.0 | f/29 |
| 200mm | f/5.6 | f/32 |
Because exposure levels are controlled by the camera, in all but the manual exposure mode, automatic exposure adjustments will be applied when the focal length changes. Photographers wanting to make use of the widest-available apertures should take note of the increase in potential depth of field as focal length increases.
Who’s it For?
The small size and light weight make this lens ideal for walkaround photography and particularly well suited to street shooting and travel. Effective weather-resistant sealing and a fluorine coating on the front element make it usable in outdoor environments, where it should be able to withstand a light rain shower as well as blown dust or spray.
The relatively slow maximum apertures are a direct consequence of the need to keep the size, weight and price of the lens as low as possible without unnecessarily compromising optical performance. Tamron appears to have managed these tasks very well.
The minimum focus distance of 19 cm provides roughly one third life size reproduction with a working distance of just 5 cm between the front element and the subject at 28mm. At the 200mm focal length, the maximum magnification is a bit over one quarter life size with a working distance of 60 cm, which allows enough space for photographing live insects.
Potential purchasers should note this lens is not stabilised. So you’ll needs to rely on the sensor-based image stabilisation that is provided in all Sony Alpha cameras.
Build and Ergonomics
The light weight of this lens is due, at least in part, to the extensive use of polycarbonate plastic in its construction. Fortunately, build quality is generally very good with no detectable flexing when the inner barrel is extended and equally tight tolerances on other moving parts.
The smooth, low-sheen outer barrel, narrow shape and white lettering fit well with the design of Sony’s full frame cameras. Weather-resistant sealing is located at six points where ingress of moisture or dust is possible, as shown in the diagram below.
This diagram shows the locations of the various dust- and moisture-excluding seals in the lens. (Source: Tamron.)
The lens extends by 55 mm when it’s zoomed from 28mm to 200mm, which reveals two inner barrels. A 10 mm wide section at the front of the extension has an internal thread for 67 mm filters with an external bayonet mounting for the supplied lens hood.
The rubber-coated zoom ring sits at the end of the outer barrel. It’s 44 mm wide and ends in a 7 mm wide uncoated band that carries the focal length markings. Zooming is very smooth, with a nice amount of resistance. A zoom lock is located in the 15 mm wide section of the outer barrel just behind the zoom ring.
The focusing ring has narrower ridging which covers its surface. It’s 13 mm wide and turns through 360 degrees when no power is available, since focusing is driven from the camera.
Another 13 mm wide section of the barrel behind the focusing ring carries the branding and lens name. The barrel then slopes inwards to end in a solid metal mounting plate.
The lens is supplied with the HA036 lens hood, which is petal-shaped and made from plastic with a ribbed inner surface to minimise internal reflections. While it lacks a locking button it’s easy to fit and remove and reverses over the barrel for transport and storage.
Performance
Outstanding performance is seldom expected from extended-range zoom lenses because of the compromises made in designing this type of lens. However, when tested on the Sony Alpha 1 camera, the review lens delivered surprisingly good results.
Our Imatest tests were conducted with all the in-camera corrections in the Alpha 1 camera enabled (although we also checked a selection of raw files captured simultaneously to identify areas that were potentially problematic). Meeting resolution expectations for a 50-megapixel sensor is a big ask but the highest resolutions measured for this lens in both JPEGs and converted ARW.RAW files came very close.
The best results were obtained at f/5.6 with the 35mm focal length although the overall performance of the lens was surprisingly consistent across its aperture and focal length ranges. Relatively high resolutions were maintained up to the f/11 aperture setting, where diffraction began to take effect, as shown in the graph of our test results below.
Lateral chromatic aberration in JPEG files remained mostly within the ‘negligible’ band for all focal length and aperture settings. (The red line marks the border between ‘negligible’ and ‘low’ CA in the graph below.)
However, with raw files it had nudged up into the ‘low’ range and our test results showed the main problem was in the blue channel, where significant deviation occurred. We found no evidence of coloured fringing along high-contrast boundaries in JPEG images, confirming effective in-camera corrections. Fringing was barely visible in uncorrected raw files, confirming this aberration is not a problem for this lens.
Because both vignetting and rectilinear distortion are automatically corrected by the camera’s JPEG processing, we had to assess these potential problems by looking at uncorrected raw files. Vignetting was barely noticeable with maximum apertures at shorter focal lengths but had become visible by 200mm at the maximum aperture of f/5.6. Stopping down one stop caused it to disappear.
There was slight barrel distortion at 28mm, which had transitioned to just detectable pincushion distortion at 35mm and increased as the lens was zoomed in.
We found the review lens to be quite resistant to ghosting and flare, thanks in part to the generous lens hood and BBAR coating. There was little evidence of either defect, even with a bright light at the edge of the frame.
Autofocusing was usually fast and accurate with medium-distance subjects in good light. The only time we encountered bothersome hunting was when the subject was close to the focus limits and this occurred at all focal length settings.
Bokeh at the widest apertures was a bit choppy and highlight outlining was common. On the plus side, highlights remained roughly circular close to the edges of the frame at all focal length settings.
Conclusion
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SPECS
Picture angle: 60 to 24 degrees
Minimum aperture: f/16-f/32
Lens construction: 18 elements in 14 groups (including 2 GMA, 2 hybrid aspherical, 1 XLD and 2 LD elements)
Lens mounts: Sony FE
Diaphragm Blades: 7 (circular aperture)
Weather resistance: Yes, 8 rubber gaskets plus fluorine coat on front element
Focus drive: an RXD (Rapid eXtra silent stepping Drive) stepping motor, internal focusing
Stabilisation: No
Minimum focus: 19 cm at 28mm, 80 cm at 200mm
Magnification ratio: 1:3.1 at 28mm, 1:3.8 at 200mm
Filter size: 67 mm
Dimensions (Diameter x L): 74 x 117 mm
Weight: 575 grams
Standard Accessories: End caps, petal-shaped lens hood
Distributor: Blonde Robot, (03) 9023 9777
TESTS
Based on JPEG files taken with the Sony Alpha 1 camera.
Based on ARW.RAW files recorded simultaneously and converted into TIFF format with Adobe Camera Raw.
SAMPLES
Vignetting at 28mm f/2.8.
Vignetting at 50mm f/3.5.
Vignetting at 100mm f/4.5.
Vignetting at 200mm f/5.6.
Rectilinear distortion at 28mm.
Rectilinear distortion at 50mm.
Rectilinear distortion at 100mm.
Rectilinear distortion at 200mm.
28mm focal length, ISO 100, 1/400 second at f/11.
200mm focal length, ISO 100, 1/320 second at f/11.
Close-up at 28mm focal length, ISO 100, 1/400 second at f/2.8.
Close-up at 50mm focal length, ISO 100, 1/1250 second at f/3.5.
Close-up at 200mm focal length; ISO 100, 1/320 second at f/5.6.
Backlit close-up at 28mm focal length, ISO 100, 1/1600 second at f/2.8.
200mm focal length, ISO 100, 1/320 second at f/7.1.
Crop from the above image enlarged to 100%.
200mm, ISO 100, 1/800 second at f/10.
Crop from the above image enlarged to 100%.
110mm focal length, ISO 100, 1/800 second at f/10.
Crop from the above image enlarged to 100%.
129mm focal length, ISO 500, 1/40 second at f/16.
Crop from the above image enlarged to 100%.
151mm focal length, ISO 100, 1/800 second at f/5.6.
Crop from a raw file captured of the above image with no corrections enlarged to 100% to reveal any coloured fringing.
140mm focal length, ISO 100, 1/1250 second at f/5.
Close-up portrait; 200mm focal length, ISO 125, 1/50 second at f/5.6.
200mm focal length, ISO 100, 1/1000 second at f/5.6.
174mm focal length, ISO 100, 1/1250 second at f/8.
144mm focal length, ISO 100, 1/50 second at f/14.
200mm focal length, ISO 125, 1/640 second at f/6.3.
200mm focal length, ISO 100, 1/1000 second at f/5.6.
130mm focal length, ISO 100, 1/320 second at f/5.6.
Close-up at 28mm focal length, ISO 100, 1/1600 second at f/5.6.
Rating
RRP: AU$1299; US$729
- Build: 8.9
- Handling: 9.1
- Image quality: 8.9
- Autofocusing: 8.9
- Versatility: 9.0
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