Tamron’s 18–270mm Di II lens has been designed for photographers entering the DSLR market after shooting with compact cameras with 10–15x zoom lenses, or for travel photographers looking for an all-in-one lens to avoid swapping lenses on their trip. So this lens falls into the ‘super-zoom’ category and — though it is handy to not to carry around more than one lens — by trying to cover such a wide focal range there are some compromises all of these lenses make due to the physics of optics. The lens itself is nice and light, which is good for a traveller, but with the body made up of mostly plastic and some metal it won’t stand up to a lot of abuse. When the lens is attached to a mid-sized DSLR it feels balanced, but when attached to some of the smaller models it gets top heavy. Also, when walking around with it over your shoulder it tends to suffer from lens creep, where the weight of the lens causes it to extend out on its own. There is a zoom lock on the lens to prevent this from happening but that does not help when trying to use the lens on a tripod pointing it up or down to take a long exposure.
Though Tamron says that the lens is an 18–270mm zoom, its range is 29–432mm on an APS-C sensor. The 18–270mm is based on what the lens would cover on a 35mm full-frame sensor body, which it is not designed to be used with. Tamron calls it a ‘macro’ lens as it will focus at an impressively close distance of 0.5m throughout the zoom range, but the focus is quite varied depending on the aperture and zoom settings. When kept at a constant focal length the point of focus shifted considerably as the aperture was stopped down.
The motor inside the lens is probably the weakest point of the camera. It is significantly slower than other super-zooms on the market and struggles to find focus in some fairly normal lighting situations, even more so when zoomed in. The lens does feature Tamron’s Vibration Compensation and is fairly effective at image stabilization, giving up to three extra stops when shooting handheld, which come in handy at night or in low-light situations.
Probably one of the biggest issues all super-zoom lenses face is chromatic aberration. With this lens there is a slight red/cyan shift between 18mm and 35mm and a significant green/magenta shift between 200mm and 270mm. Also with such a wide zoom range there is some vignetting at 18mm, but this seems to disappear when aperture is at f/4.5 or smaller. Overall, the images are sharpest when the lens is between 35–100mm and set between f/5.6–11.
This article is from D-Photo issue 51. Get your copy here.
- Focal length: 18–270mm
- Maximum aperture: f/3.5–f/6.3
- Minimum aperture: f/22(18mm)–f/40(270mm)
- Image stabilization: Yes
- Aperture blades: Seven
- Optical construction: 16 elements in 13 groups
- Minimum focus: 0.49mm
- Maximum magnification: 1.3:8
- Dimensions (WxH): 74.4x 96.4mm
- Weight: 450g