In summary
The SP AF 45mm f/1.8 DI VC USD and its 35mm focal length companion have been designed for purists; photographers who require top performance with few, if any, compromises.
The 45mm focal length will be attractive to owners of ‘full frame’ cameras because it provides field-of-view coverage that is similar to normal vision. Its diagonal is marginally narrower than the diagonal of a 36 x 24mm image sensor, which gives this lens a slightly different perspective from a standard 50mm lens.
We tested the review lens on both the Canon EOS 5D Mark II and EOS 7D camera bodies to show any differences in performance between a ‘full frame’ DSLR and one with an APS-C sensor. Subjective assessments of test shots showed the lens to be a good performer on both camera bodies, although, as expected, there was slightly less edge softening on the camera with the smaller sensor because it crops out the edges of the frame.
Full review
Tamron’s new SP AF 45mm f/1.8 DI VC USD prime lens has few rivals, being slightly wider than a standard 50mm focal length, having a fast (f/1.8) maximum aperture and including weatherproof sealing and integrated stabilisation. It’s also usable on DSLRs with APS-C cropped sensors, where its equivalent focal length is 67.5mm for Nikon or 72mm for Canon. Tamron offers this lens in Canon and Nikon mounts, with a Sony mount version without in-built stabilisation to come. (Sony Alpha DSLRs have built-in stabilisation.)
Angled view of the SP AF 45mm f/1.8 DI VC USD prime lens without its lens hood and end caps. (Source: Tamron.)
The optical design comprises 10 elements in 8 groups and includes one LD (Low Dispersion) element to minimise chromatic aberrations and two moulded glass aspherical elements to ensure edge-to-edge sharpness and even light transmission throughout the aperture range. Proprietary eBAND (Extended Bandwidth & Angular-Dependency) and BBAR (Broad-Band Anti-Reflection) coatings have been applied to reduce surface reflections and prevent lens flare and ghosting.
The diagram above shows the positions of the exotic lens elements in the optical design. (Source: Tamron.)
Nine diaphragm blades close to a circular aperture for smooth background blurring. The lens is supplied with a petal-shaped hood plus front and end caps. SILKYPIX Developer Studio 4.0 for Tamron software is included with the lens; but we’d advise against using it as there are many better-performing alternatives, including Adobe Camera Raw and PhaseOne Capture One.
Who’s it For?
The SP AF 45mm f/1.8 DI VC USD and its 35mm focal length companion have been designed for purists; photographers who require top performance with few, if any, compromises. The 45mm focal length will be attractive to owners of ‘full frame’ cameras because it provides field-of-view coverage that is similar to normal vision. Its diagonal is marginally narrower than the diagonal of a 36 x 24mm image sensor, which gives this lens a slightly different perspective from a standard 50mm lens.
On cropped sensor cameras, the perspective isn’t quite so novel. The 67.5mm for Nikon and Sony cameras or 72mm for Canons are covered by most standard zoom lenses so the main advantage of the Tamron 45mm lens is its fast maximum aperture.
Check out the feature list below to see whether this lens merits a place in your camera bag.
1. The f/1.8 maximum aperture allows the lens to be used hand-held in dim lighting and also provides a high level of selective focus control.
2. Built-in VC (Vibration Compensation) stabilisation enables photographers to shoot with slower shutter speeds, further extending low-light capabilities.
3. Autofocusing is driven by an Ultrasonic Drive (USD), with an actuator that converts ultrasonic waves into rotational motion. The system is fast, quiet and accurate and manual over-ride is always available while the AF system is operating.
4. The lens is sealed to prevent moisture from entering and damaging its internal mechanisms. This allows it to be used outdoors in adverse conditions.
5. Advanced lens coatings produce sharp, crisp images and suppress ghosting and flare.
6. The minimum object distance (MOD) of 29 centimetres provides some scope for shooting close-ups. Tamron claims this lens offers best-in-class close focusing, thanks to its floating element design.
Build and Ergonomics
The metal outer barrel, moisture-resistant sealing and solid plastic lens hood and end caps add up to superior build quality and help justify the relatively high price of this lens. It also feels quite solid and it half-kilogram weight makes it better suited to larger DSLRs, such as the Canon EOS 5D II and EOS 7D bodies we used for our tests.
The front element is recessed by about 12 mm behind the filter ring. It’s a bit over 4 cm in diameter and has a fluorine coating to repel moisture and grease, making it easy to keep the lens clear of fingerprints and smudges.
The supplied lens hood attaches to a bayonet mounting on the outer surface of the lens. Immediately behind it is the focusing ring, which is 28 mm wide and has a finely-ridged grip band covering 25 mm of its width.
This ring turns smoothly as it is rotated through the 190 degrees required to span the focusing range. A recessed distance scale is located just behind the focusing ring on a 44 mm long section of the lens barrel. It carries Imperial and metric distances spanning from 0.35 metres to infinity.
Slightly behind the distance scale and around the left hand side of this section of the lens barrel are slider switches for engaging auto or manual focus and switching the VC stabilisation on or off. The words ‘Designed in Japan’ are stamped on the outer barrel to the left of the VC on/off switch.
The outer barrel ends in an 8 mm wide brushed silver ring that surrounds the narrow, soft rubber gasket sealing off the interface between the lens and the camera body. Inside it is the metal mounting plate, which surrounds the gold-plated electronic contacts. The rear element of the lens is about 30 mm in diameter and recessed into the inner barrel.
The lens is supplied with end caps and a generous, petal-shaped lens hood, all made from solid black polycarbonate plastic. Unlike some other manufacturers, Tamron doesn’t supply a carrying pouch with this lens.
Performance
We tested the review lens on both the Canon EOS 5D Mark II and EOS 7D camera bodies to show any differences in performance between a ‘full frame’ DSLR and one with an APS-C sensor. Subjective assessments of test shots showed the lens to be a good performer on both camera bodies, although, as expected, there was slightly less edge softening on the camera with the smaller sensor because it crops out the edges of the frame.
Imatest confirmed our subjective assessments and showed the lens to be capable of meeting the expectations for the camera’s sensor at most focal length settings with measurements in the centre of the frame. Resolution fell below expectations at the widest apertures and also from about f/8 on, where diffraction kicked in. The graph below shows the results of our tests.
Lateral chromatic aberration remained within the negligible band for all focal length and aperture settings with both cameras. We found no significant coloured fringing in any of our test shots. In the graph below showing the results of our tests, the red line marks the border between negligible and low CA
.
Some vignetting (edge and corner shading) was observed in test shots taken at f/1.8 with both cameras but assessments of uncorrected raw files showed little in the way of corner darkening by f/2.8. Very slight barrel distortion could be seen in converted CR2.RAW files from both cameras. Both distortions can be corrected in-camera in the latest DSLRs as well as post capture in standard raw file converters so neither problem is a deal-breaker for this lens.
Autofocusing speeds weren’t quite as fast as we’d like, particularly when moving between the closest focus and infinity, which took a little over one second. However the AF system operated almost silently, thanks to the USD (Ultrasonic Silent Drive) motor. Manual focusing was straightforward, thanks to a solid focusing ring, which turned smoothly.
We tested the capabilities of the VC (Vibration Compensation) stabilisation system with the EOS 7D body because it magnifies any vibrations by 1.6x. We were able to hand-hold the camera at shutter speeds as slow as 1/8 second and obtain more than 60% of the images we recorded sharply focused. This is equivalent to approximately 3.5 f-stops of shake compensation, which matches the manufacturer’s claims.
Strong backlighting was handled extremely well, and it was difficult to force the lens to reveal signs of flare and ghosting, even when a bright light source was inside the image frame. Contrast remained high in backlit shots and there were no signs of veiling flare.
With a close focusing limit of 29 cm, this lens isn’t ideal for shooting close-ups but it can be used to photograph larger flowers and small animals. Bokeh at f/1.8 was a mixed bag. We found strong outlining when bright out-of-focus highlights were present in the backgrounds with both cameras. However, when backgrounds were more evenly lit, out-of-focus areas were pleasantly smooth, remaining so until about f/2.8 when the wider depth of field made background details visible.
Conclusion
There was plenty of media hype when Tamron announced its new f/1.8 prime lenses so it was good to have a chance to see how much of it was based on real life experiences. The answer is complex.
In some ways the new 45mm f/1.8 lens is a good performer; not great, but certainly good. Our Imatest tests showed it to be capable of reaching expectations for the sensor resolutions of the two cameras we tested it on, neither of which is the latest model in its line. But it didn’t exceed expectations to any degree and we feel it might not be able to match the resolutions of newer and higher-resolution sensors.
Vignetting, distortion and chromatic aberration were all relatively low; but all three are easily corrected either in-camera or in post-production. Bokeh could be smooth or choppy, depending on the nature of the background. Autofocusing was adequate but not really fast.
There’s plenty of competition in the standard focal length arena, particularly at the 50mm position where all the major manufacturers have at least one relatively fast prime lens. Many of them ““ including some with f/1.8 maximum apertures ““ are quite a bit cheaper than the Tamron lens.
So if you’re pondering on whether to add this lens to your kit, ask yourself just how important the 45mm focal length is to your photography and whether you really need a prime 45mm lens with weatherproof sealing. Then shop around for a competitive price and decent pre- and post-purchase service.
Already a number of Australian websites have this lens listed at under $1000, which makes the listed price of US$599 on several US websites relatively uncompetitive. You’d be better off buying it from a local re-seller who can provide you with hands-on time and good advice as well as better post-purchase service.
SPECS
Picture angle: 51 degrees 21 minutes for full-frame format; 34 degrees 28 minutes for APS-C format
Minimum aperture: f/16
Lens construction: 10 elements in 8 groups (including two moulded glass aspherical lens elements and one LD element)
Lens mounts: Canon, Nikon, Sony (without VC)
Diaphragm Blades: 9 (circular aperture)
Focus drive: USD (Ultrasonic Drive)
Stabilisation: VC (Vibration Compensation)
Minimum focus: 29 cm
Maximum magnification: 1:3.4
Filter size: 67 mm
Dimensions (Diameter x L): 80.4 x 91.7 mm
Weight: 540 grams
Standard Accessories: Flower-shaped lens hood, front and end caps
TESTS
Based on JPEG files taken with the Canon EOS 5D Mark II camera.
Based on JPEG files taken with the Canon EOS 7D camera.
SAMPLES
EOS 5D II; vignetting at f/1.8. (Taken from an uncorrected raw file.)
EOS 7D; vignetting at f/1.8. (Taken from an uncorrected raw file.)
EOS 5D II; rectilinear distortion. (Taken from an uncorrected raw file.)
EOS 7D; rectilinear distortion. (Taken from an uncorrected raw file.)
EOS 5D II; ISO 125, 1/500 second at f/5.6.
EOS 7D; ISO 100, 1/320 second at f/5.6.
EOS 5D II close-up; ISO 125, 1/250 second at f/7.1.
EOS 7D close-up; ISO 200, 1/320 second at f/7.1.
EOS 5D II flare; ISO 100, 1/1000 second at f/8.
EOS 7D flare; ISO 100, 1/1000 second at f/8.
Stabilisation test with EOS 7D; ISO 200, 1/8 second at f/3.5.
Bokeh with EOS 5D II; ISO 100, 1/5000 second at f/1.8.
Bokeh with EOS 7D; ISO 200, 1/4000 second at f/1.8.
EOS 7D at f/1.8; ISO 100, 1/4000 second at f/1.8.
EOS 7D at f/2.5; ISO 100, 1/2500 second at f/2.5.
EOS 7D at f/4; ISO 100, 1/1000 second at f/4.
EOS 7D at f/5.6; ISO 100, 1/800 second at f/5.6.
Rating
RRP: AU $1099
- Build: 8.9
- Handling: 8.8
- Image quality: 8.8
- Versatility: 8.5