11th August 2011 12:15 PM
Tamron 18-270mm f/3.5-6.3 PZD Review
The Tamron 18-270mm f/3.5-6.3 Di II VC PZD is the world's smallest and lightest 15x zoom for crop-sensor DSLRs. From wide-angle (approx. 28mm full frame equivalent) to supertelephoto (approx. 432mm full frame equivalent), it offers a level of convenience and reach that no other consumer lens in the market can match. But how does it perform? Read on to find out.
First, let's get some of Tamron's acronyms out of the way:
Di II: means that the Tamron 18-270 PZD can only be used with crop-sensor APS-C DSLRs. It's available in Canon, Nikon, and Sony mounts.
VC: stands for Vibration Compensation, Tamron's implementation of image-stabilisation.
PZD: stands for Piezo Drive, whcih makes use of a piezoelectric motor to silently drive the AF motor.
The Tamron 18-270 PZD has 13 elements in 16 groups, including two LD (Low Dispersion), one AD (Anomalous Dispersion), one Hybrid Aspherical, and two Glass Molded Aspherical elements. This results in impressive image quality despite the huge zoom range. Seven diaphragm blades produce pleasing bokeh, and a minimum focusing distance of 0.49m gives the Tamron 18-270 PZD decent macro capability with 1:3.8 magnification at 270mm. As with all other Tamron lenses, the 18-270 PZD comes with a lens hood in the box.
Filter diameter is 62mm, and the front element does not rotate while focusing or zooming, allowing photographers to easily use filters of their choice.
Construction and Handling
The Tamron 18-270 PZD has a plastic construction on a metal mount. Despite the lens' light weight, it feels solid and well-built. Zooming from 18mm to 270mm almost doubles the lens' length, from approximately 9cm to 17cm. For reference, a Canon 70-200mm f/4 L is approximately 18cm long. Of course, the Tamron 18-270 PZD covers a much larger zoom range at a similar size. Despite it's large zoom range, the Tamron 18-270 PZD weighs in at only 450g.
(Click to embiggen)
The above shows the Tamron 18-270 PZD extending through the zoom range. The barrel extends in two sections; there is negligable play in the barrels when extended, which lends to the feeling of confidence in its construction. The zoom mechanism is smooth throughout the range, though resistance increases as the lens is pointed up or down, unsurprising given the amount of mass being moved about. The lens will creep if it's pointing downward and shaken, as when walking, but a zoom lock allows you to lock the lens at 18mm.
The Tamron 18-270 PZD does not have full-time manual focusing, and the focusing ring rotates while focusing. A switch toggles between autofocus and manual focus. While not as quick as Canon and Nikon's ultrasonic ring motors, autofocus in good light is quick and silent thanks to the Piezo Drive. The lens tends to hunt for focus in low-light situations, but that's par for the course for lenses with smaller maximum apertures like the Tamron 18-270 PZD, especially zoomed in.
Image stabilisation, or Vibration Compensation (VC) in Tamron's parlance, is excellent. The stability of the viewfinder is astounding once the VC motor starts up, making it possible to hand-hold shots even at 270mm. Tamron advertises up to a four-stop effectiveness, and after using the lens we're sold; it is extremely effective. In the sample gallery below is a concert photo taken at 270mm, 1/100s. Theoretically, that shot should have needed a shutter speed of 1/400s or so without VC, along with the necessary bump in ISO. Instead, the shot was taken at a shutter speed that would have been impossible without VC.
As with autofocus, VC can be toggled on and off via a switch on the side of the lens. Canon- and Nikon-mounts include the VC motor, while the Sony-mount version does not as Sony builds image stabilisation into their camera bodies.
Image Quality and Performance
To test for chromatic abberation, we shot the above scene. If uncontrolled, CA should be very obvious where the edges of the leaves meet the sky.
CA is absent from the center of the frame. At the edges however, CA becomes more apparent. However, this test shot represents a worst-case scenario for CA, and in typical shooting we have found it to be a non-issue.
To test for distortion, the above scene was shot at increasing focal lengths. To ensure an accurate comparison, the camera was moved further and further away from the window as focal length increases in order to ensure a similar field of view. The image below shows our results (click for full size).
If we were to choose the biggest flaw with the Tamron 18-270 PZD, it would be distortion. Barrel distortion is quite severe at 18mm, with pincushioning setting in as early as 35mm in the zoom range. Pincushion distortion is most severe at 50mm, though it does subside some by 100mm. To summarise, some for of distortion is present throughout the zoom range, and users of this lens will do well to shoot around this limitation or be prepared to correct it in post-processing.
There's no such thing as a perfect lens; adding a feature in a lens design necessitates some sort of compromise elsewhere. One must understand and be prepared to shoot around the limitations of the lens. In the case of the Tamron 18-270mm f/3.5-6.3 Di II VC PZD, its primary selling feature (15x zoom range) belies persistant distortion and some CA.
However, as a do-it-all superzoom it is definitely an excellent buy. Image quality is very similiar to the first party 18-200mm superzoom offerings from Canon and Nikon, but the Tamron has further reach. If you're in the market for a small, lightweight lens that will cover almost all focal ranges, this is the lens for you. It's perfect for travel photography and for times when you don't want to lug an entire kit of lenses around. For any photographer looking to maximise convenience, the Tamron 18-270mm f/3.5-6.3 Di II VC PZD certainly is a compelling option.
One of the key selling points of this lens is its versatility; in light of that, we attempted to bring the Tamron 18-270 PZD to as many different locales as possible in order to capture a variety of images.
(169mm, f/6.3, 1/80s, ISO640, +0.33EV)
Although the maximum aperture of the Tamron 18-270 PZD isn't large, it's long focal lengths allow it to blur the background nicely.
(119mm, f/5.6, 1/125s, ISO2000, +0.33EV)
Bokeh is quite pleasing, with circular highlights.
(21mm, f/3.5, 1/2500s, ISO1600, -0.33EV)
Shot wide-open, the Tamron 18-270 PZD has very good center sharpness, although it gets slightly soft at the edges.
(18mm, f/7.1, 1/1000s, ISO200, +0.33EV)
The Tamron 18-270 PZD controls flare as well, even in a challenging scene such as this.
(270mm, f/7.1, 1/100s, ISO2000)
Notice the shutter speed at which this shot was taken; impossible without VC!
(155mm, f/7.1, 1/640s, ISO250)
That's the top of Marina Bay Sands, shot from ground level. With the Tamron 18-270 PZD, you have great reach in a small package.
(100mm, f/5.6, 1/100s, ISO640, +1.33EV)
Again, we see the Tamron 18-270 PZD is no slouch when it comes to subject isolation despite it's small maximum aperture.
Last edited by CCJ; 11th August 2011 at 04:57 PM.
11th August 2011 06:15 PM