Tamron 17-70mm f/2.8 Di III-A VC RXD lens for Fujifilm X-mount
We found the 17-70mm f/2.8 Di III-A VC RXD lens to be a comfortable match for the Fujifilm X-T3 camera we used for our tests, which means it should work equally well with later versions of the camera, including the new X-T5. It was nicely balanced and neither too large nor too heavy to make it burdensome.
Ideally suited to travel and street photography, this lens can also be used for photographing landscapes and architecture as well as everyday snapshooting. It’s also keenly priced to be affordable by most photo enthusiasts – and even family photographers who want to be able to capture sharp stills and videos.
Tamron’s latest 17-70mm standard zoom lens is the Fujifilm version of the 17-70mm f/2.8 Di III-A VC RXD lens, which was released on January 14, 2021 for Sony E-mount APS-C mirrorless cameras. It features a constant f/2.8 maximum aperture and a 4.1x zoom ratio that covers the equivalent of 25.5-105mm in 35mm format plus a VC (Vibration Compensation) mechanism to suppress camera shake. We reviewed the lens on a Fujfilm X-T3 camera body.
Angled view of the Tamron 17-70mm f/2.8 Di III-A VC RXD lens for Fujfilm X-mount cameras. (Source: Tamron.)
The optical design of this lens consists of 16 elements in 12 groups and includes two LD (low dispersion), two GM (glass moulded) aspherical and one hybrid aspherical elements to maintain high resolution from edge-to-edge. BBAR (Broad-Band Anti-Reflection) Coating has been applied to individual elements in order to suppress internal reflections, flare, and ghosting. A nine-bladed iris diaphragm creates a circular aperture for attractive bokeh.
The optical design of the Tamron 17-70mm f/2.8 Di III-A VC RXD lens showing the positions of the exotic glass elements. (Source: Tamron.)
Autofocusing is driven by a quiet RXD (Rapid eXtra-silent stepping Drive) motor that is fast and has minimal focus breathing, making it ideal for shooting video. This lens has a minimum focus of 19 cm at 17mm and 39 cm at 70mm, with magnification ratios of 1:4.8 and 1:5.2, respectively.
A moisture-resistant construction and fluorine coating on the front element make it easy to keep clean on location shoots. Like most Tamron lenses in its class, it accepts 67 mm filters. The Fujifilm version weighs 530 grams and comes with a petal-shaped lens hood.
Who’s it For?
The 4.1x zoom range is quite modest but the wide-angle to short-telephoto coverage makes this a useful general-purpose lens for everyday shooting and travel photography. The fast and constant f/2.8 maximum aperture enables it to be used in a wide range of difficult lighting conditions and also offers good control over depth of field.
Adding to its low-light versatility is the integrated VC image stabilisation system, which expands options for hand-held stills and video recording in low-light conditions. The RXD stepping motor enables quick, near-silent autofocusing, along with full-time manual focus override.
The moisture-resistant construction and fluorine-coated front element make it ideal for outdoor use, including in inclement conditions, and easy to clean if the lens is exposed to dust, sand or spray. It is also compatible with the dedicated Tamron Lens Utility software that enables users to customise focus ring settings and install firmware updates when they are released.
Build and Ergonomics
Tamron doesn’t specify the materials used in the construction of this lens but, going on its similarity to other Tamron lenses we’ve reviewed recently, we’d say the outer and inner barrels are made mostly of composite polycarbonate on a metal mount. Build quality is very sound and up to the company’s usual high standard.
The front element is approximately 55 mm in diameter and recessed a little to allow for a threaded rim that allows 67 mm diameter filters to be fitted. The outer edge of the inner barrel has a bayonet fitting for the supplied lens hood, which is made from hard black plastic.
The zoom ring is located at the front of the outer barrel. It’s approximately 40 mm wide and mostly covered in rubber ridging that is slightly thicker than the focusing ring’s to make it identifiable by touch.
An unridged 6 mm wide band behind the rubber ridging carries markings for focal length settings for 17mm, 24mm, 35mm 50mm and 70mm focal lengths, which are lined up against an index mark on the fixed section of the barrel behind the ring. The inner barrel extends by almost 30 mm without changing its orientation when you zoom from 17mm to 70mm. Zooming is smooth and positive with no slack and the internal adjustments ensure hassle-free use of angle-critical filters and other attachments.
A 9 mm wide band separates the zoom and focusing rings. The focusing ring is approximately 14 mm wide and is entirely covered with ridging that is slightly finer than the zoom ring’s. Since focusing is driven from the camera, this ring turns through 360 degrees when power is not supplied.
Behind the focusing ring is a 16 mm fixed section of the barrel that carries the lens data (brand name and model) on the top surface with ‘Designed in Japan’ around the left had side and a ‘Made in Vietnam’ label plus a range of CE icons on the base. The barrel slopes inwards for another 11 mm to another flat 8 mm wide band that ends in a 2 mm wide slope to a silver branding ring.
The lens ends in a solid metal mounting plate with a bayonet fitting for X-mount cameras plus 10 electronic contacts inside the fitting for passing data between the camera and the lens.
Our Imatest tests showed the review lens to be an excellent performer with the best measured performance measured in the centre of the frame at the 24mm focal length with an aperture of f/3.5. As expected, resolution declined towards the edges of the frame, which is common with many zoom lenses we’ve tested.
As shown in the graph of our test results above, JPEG resolution remained high for all focal lengths and across aperture settings to around f/8, where diffraction began to take effect. It was significantly higher for RAF.RAW files, which also recorded a noticeably wider dynamic range.
Because the camera provides internal corrections for JPEGs, our lateral chromatic aberration measurements are based on RAF.RAW files from the X-T3 camera we used for our tests. In the graph of our test results above, the vertical red line marks the boundary between ‘negligible’ and ‘low’ CA.
Both vignetting and rectilinear distortion had to be assessed through raw files with all optical and profile corrections disabled in Adobe Camera Raw. Although we found slight vignetting at the widest apertures across all focal lengths, it was most obvious with the 17mm and 70mm focal lengths. In most cases it was gone by f/3.5.
There was obvious barrel distortion in uncorrected raw files at 17mm but by 24mm very little distortion could be seen. At 50mm, pincushion distortion became evident and it was obvious at 70mm. Both vignetting and rectilinear distortions are largely irrelevant since they are corrected automatically in JPEGs and most raw file converters.
We encountered no instances of visible flare in any of our test shots, except for some minor flare artefacts in our sunstars test shots at 70mm. The combination of an effective lens hood and anti-reflection coatings on the lens elements have obviously played key roles in this result.
Bokeh was as expected from such a fast zoom lens with a very shallow depth of field at its maximum aperture. Out-of-focus transitions were smooth, with highlights nicely rendered and little evidence of outlining around brighter areas.
Autofocusing was generally fast and accurate in widely different lighting conditions, including after dark. It was also virtually silent, enabling this lens to be used for recording videos. We found no evidence of focus breathing.
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Picture angle: 79 degrees 55 minutes to 23 degrees
Minimum aperture: f/22
Lens construction: 16 elements in 12 groups (including 2 glass-moulded aspherical, 1 hybrid aspherical two LD elements plus fluorine coating on front element)
Lens mounts: Fujifilm XF
Diaphragm Blades: 9 (rounded aperture)
Weather resistance: Moisture-resistant (sealed in nine places)
Focus drive: RXD (Rapid eXtra-silent Drive) stepping motor mechanism
Minimum focus: 19 cm at 17mm / 39 cm at 70mm
Maximum magnification: 1:5.2 at 70mm
Filter size: 67 mm
Dimensions (Diameter x L): 74.6 x 119.6 mm
Weight: 530 grams
Standard Accessories: Front and end caps, petal-shaped lens hood
Distributor: Blonde Robot, (03) 9023 9777
Based upon JPEG files taken with the Fujifilm X-T3 camera.
Based on RAF.RAW files recorded simultaneously and converted into 16-bit TIFF format with Adobe Camera Raw.
Vignetting at 17mm f/2.8.
Vignetting at 24mm f/2.8.
Vignetting at 35mm f/2.8.
Vignetting at 50mm f/2.8.
Vignetting at 70mm f/2.8.
Rectilinear distortion at 17mm.
Rectilinear distortion at 24mm.
Rectilinear distortion at 35mm.
Rectilinear distortion at 50mm.
Rectilinear distortion at 70mm.
17mm focal length, ISO 100, 1/500 second at f/9.
24mm focal length, ISO 100, 1/500 second at f/9.
35mm focal length, ISO 800, 1/13 second at f/11.
50mm focal length, ISO 800, 1/15 second at f/11.
70mm focal length, ISO 800, 1/15 second at f/11.
From RAF.RAW file with corrections disabled; 17mm focal length, ISO 160, 1/85 second at f/8.
Crop from the above image at 100%magnification showing edge sharpness and absence of coloured fringing.
Close-up at 17mm f/2.8; ISO 160. 1/1900 second.
Close-up at 17mm f/2.8; ISO 160. 1/2500 second.
Close-up at 17mm f/2.8; ISO 160. 1/5800 second.
Close-up at 35mm f/2.8; ISO 160. 1/2000 second.
Close-up at 35mm f/2.8; ISO 160. 1/2700 second.
Close-up at 35mm f/2.8; ISO 160. 1/5000 second.
Close-up at 70mm f/2.8; ISO 160. 1/2000 second.
Close-up at 70mm f/2.8; ISO 160. 1/2700 second.
Close-up at 70mm f/2.8; ISO 160. 1/1700 second.
Sunstar at 17mm f/22; ISO 160. 1/17 second.
Sunstar at 35mm f/22; ISO 160. 1/20 second.
Sunstar at 70mm f/22; ISO 160. 1/26 second.
Low light AF; 70mm focal length, ISO 3200. 1/4 second at f/4.
Low light AF; 17mm focal length, ISO 3200. 0.71 second at f/5.
17mm focal length, ISO 250. 1/25 second at f/5.
70mm focal length, ISO 500. 1/105 second at f/5.6.
38mm focal length, ISO 400. 1/50 second at f/5.6.
26mm focal length, ISO 400. 1/30 second at f/5.6.
70mm focal length, ISO 800. 1/40 second at f/5.
62mm focal length, ISO 800. 1/50 second at f/5.6.
70mm focal length, ISO 160. 1/80 second at f/6.3.
17mm focal length, ISO 160. 1/170 second at f/11.
70mm focal length, ISO 160. 1/100 second at f/5.
52mm focal length, ISO 160. 1/210 second at f/5.
17mm focal length, ISO 800. 1/25 second at f/16.
70mm focal length, ISO 160. 1/140 second at f/8.
- Build: 8.9
- Handling: 9.0
- Image quality: 9.0
- Autofocusing: 8.9
- Versatility: 8.9