Tamron AF 18-270mm f/3.5-6.3 Di II VC LD Aspherical (IF) MACRO reviewDecember 2008 |  The latest design to emerge from the stable of superzoom experts Tamron, the AF 18-270mm f/3.5-6.3 Di II VC LD Aspherical (IF) MACRO was announced in July 2008. The length of the zoom range is almost as remarkable as that of the lens's name itself, with the 15x ratio covering everything from a 28mm equivalent wideangle to a 420mm equivalent telephoto. This is unprecedented in terms of SLR optics, and is clearly aimed at users upgrading from superzoom digicams who require a similar focal length range without the inconvenience of changing lenses. It also makes a compelling option as an all-in-one travel/'walkabout' solution. A minimum focus distance of just 0.5m throughout the zoom range, and the incorporation of optical image stabilization (or 'Vibration Compensation' as Tamron call it) enhance the lens's flexibility still further. It is available only in mounts for Canon and Nikon DSLRs; presumably Pentax and Sony owners will continue to be served by Tamron's existing 18-250mm F3.5-6.3, with image stabilization provided by the camera body. Making a lens with such an extraordinary range is always gong to require some pretty clever engineering, and Tamron's design team have clearly been burning the midnight oil on this one. The optical formula features no fewer than 18 elements in 13 groups, including three aspherical elements and two Low Dispersion (LD) glass elements for the control of aberrations. A 'double-trombone' mechanical design allows the lens to almost double in length between 18mm and 270mm, whilst keeping the overall size and weight very similar to competing 18-200mm lenses. The 18-270mm F3.5-6.3 VC will compete head-to-head in the 'stabilized superzoom' market with theCanon EF-S 18-200mm F3.5-5.6 IS, Nikon 18-200mm f/3.5-5.6G IF-ED AF-S VR DX, and Sigma 18-200mm F3.5-6.3 DC OS, but offering the benefit of substantially extended telephoto range. Tamron hails it as 'The Ultimate All-In-One Zoom: Longest, Steadiest Lens On Earth', and while it seems likely that this phrase may have lost something in translation, it does give a good impression the lens's appeal. But can such a general-purpose optic actually be any good? Headline features
Angle of viewThe pictures below illustrate the (frankly extraordinary) focal length range from wide to telephoto (on Nikon DX format, 1.5x).
Tamron AF 18-270mm f/3.5-6.3 Di II VC LD Aspherical (IF) MACRO specifications
* Supplied accessories may differ in each country or area Foreword / notesIf you're new to digital photography you may wish to read some of our Digital Photography Glossary before diving into this article (it may help you understand some of the terms used).Conclusion / recommendation / ratings are based on the opinion of the author, we recommend that you read the entire review before making any decision. Images which can be viewed at a larger size have a small magnifying glass icon in the bottom right corner of them, click to display a larger image in a new window. To navigate this article simply use the next / previous page buttons or jump to a specific page by using the drop-down list in the navigation bar at the top of the page. You can support this site by ordering through the affiliate links shown at the bottom of each page (where available). This article is protected by Copyright and may not be reproduced in part or as a whole in any electronic or printed medium without prior permission from the author. Dpreview use calibrated monitors at the PC normal gamma 2.2, this means that on our monitors we can make out the difference between all of the grayscale blocks below. We recommend to make the most of this review you should be able to see the difference (at least) between X,Y and Z and ideally also A, B and C. |
Design Two switches on the side control the autofocus and vibration correction mechanisms; these are noticeably larger and easier to operate than their counterparts on the Canon and Nikon 18-200mm lenses. There's also a switch to lock the zoom at 18mm, conventionally-placed on the top of the lens barrel. This is worthwhile on such a lens with its heavy front elements, which can cause the lens to extend under its own weight when the camera is carried over the shoulder. On the camera
One note of caution though; on smaller SLR bodies such as the D60, the lens will block the built-in flash at focal lengths wider than 24mm, resulting in a shadow in the lower center of the image. AutofocusThe 18-270mm VC uses a small micro-motor for autofocus, and this is the weakest point of the design. It feels rather sluggish when compared to either Nikon or Canon's 18-200mm lenses, although to be fair the motor is at least reasonably quiet (although not silent like the Nikon's AF-S motor). On the bodies used for testing (Nikon D300 and D90) AF performance was relatively slow and sometimes extremely indecisive, especially at telephoto, presumably hindered by that slow maximum aperture (most autofocus systems are only specified to work reliably with lenses that are F5.6 or brighter). On the D90, the lens was also occasionally unable to confirm focus with subjects which we'd normally not expect to be a problem, instead dithering for a few seconds before giving up and sometimes giving a clearly misfocused image. However this wasn't a particularly frequent problem; also it was normally easy enough to spot in the viewfinder when the lens was struggling, and either switch to manual focus or take a couple of 'safety shots'. As always, it must be noted that focus speed and accuracy is dependent upon a number of variables, including the camera body used, subject contrast, and light levels. Zoom creepZoom creep is the tendency for a lens to extend or under its own weight when pointed downwards (or collapse when pointed upwards), and is a fairly common characteristic of superzooms. It can be a problem when carrying the camera over your shoulder with the lens hanging downwards, as having the zoom continually extend to its maximum length is not just irritating, but also makes the lens more vulnerable to being knocked and damaged.The 18-270mm suffers from zoom creep more than most, and if you habitually carry the camera with the lens pointing downwards you'll find it setting itself to 270mm on a regular basis. With our test sample this happened pretty well any time the lens was set to a focal longer of 35mm or longer; conversely at 200mm or shorter and with the camera pointed upwards, the lens tended to collapse towards 18mm. Now if you're prepared to reset the lens to 18mm between shots then the problem essentially goes away (ironically the lens tends not to creep at all at this focal length, making the zoom lock switch near-redundant). Also if you prefer to carry the camera in your hand with the lens horizontal rather than vertical, creep effectively becomes a non-issue too. However zoom creep can also be a problem when pointing the camera either upwards or downwards when shooting, as it means that the lens can attempt to zoom under its own weight; this isn't much of a problem when shooting hand-held (simply keep hold of the zoom ring), but can become a genuine problem when shooting at slow shutter speeds with the camera on a tripod, at which point holding the zoom ring is not an option. To be fair this is not a typical scenario with this lens (the whole point of a stabilized superzoom is to travel light, which likely means leaving the tripod behind), but it could be a concern to some users. Dependence of apparent focal length on focus distanceThis lens's angle of view widens dramatically on focusing from infinity to 0.45m, especially at the telephoto end. This is a common trait with superzooms (the Canon and Nikon 18-200s behave in just the same way), but it does mean that at a focus distance of 2m, that 270mm telephoto ends up looking more like 180mm. In context, it is worth bearing in mind that long telephotos generally tend to used more for distant subjects, in which case the lens naturally behaves as a 'true' 270mm.Lens body elements
Reported aperture vs focal lengthHere we show the maximum and minimum apertures reported by the camera at the marked focal lengths.
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