AP was the first UK outlet to get hands-on with Tamron’s new superzoom, which covers an astonishing zoom range and benefits from a light and compact form factor. Michael Topham tests the first working sample
Tamron 18-400mm f/3.5-6.3 Di II VC HLD review: Image Quality
Before analysing image quality, I conducted several image stabilisation tests throughout the focal range. The lens’s VC system performs admirably and I had no difficulty shooting sharp handheld shots at as slow as 1/8sec at the wide end of the zoom. Pushing to the furthest extent of the zoom, I also managed to shoot a number of sharp frames of a static subject using a shutter speed as low as 1/25sec.
After inspecting images taken with the lens, I analysed our lab results, which matched my real-world findings. The lens produces its sharpest results at the widest end of the zoom range, with edge-to-edge sharpness peaking at f/5.6. Zooming in to around 70mm sees a slight drop in sharpness that is most noticeable at the corners. Stopping down to f/8 does improve centre and edge sharpness at this focal length, but the impact of diffraction does soften overall sharpness beyond f/11.
There’s usually a compromise you have to make on choosing a lens that covers such a wide focal range and this comes in the form of sharpness at the long end of the zoom. As the sample images that support this review show, it is possible to walk away with usable results from using the lens at 400mm, however users shouldn’t expect to be overwhelmed by the level of sharpness at the long end. In general, this lens offers its best results with the aperture set between f/5.6 to f/11. Avoid pushing to f/16 and beyond and you’ll reduce the risk of diffraction softening overall sharpness.
With regard to distortion, there’s obvious barrel distortion at the wide end that turns to pincushion distortion rather rapidly in the focal range. Unfortunately there’s no way for third-party lenses to benefit from in-camera distortion correction with either Canon or Nikon DSLRs, meaning you’re best off shooting in raw so you can correct for it easily later in post-processing as soon as a lens profile becomes available.
As for vignetting, this is quite obvious when shooting wide-open, particularly at the widest end of the zoom where it’s at its most severe. Stopping down to f/5.6 does see an improvement, but stopping down to f/8 can minimise it further. Again, it’s advised to shoot in raw so the light fall-off towards the corners can be rectified easily with a one-click fix in your raw converter.
A close examination of raw files revealed the lens exhibits quite obvious chromatic aberration through its zoom range too. At wideangle settings I noticed traces of green and purple fringing along high-contrast edges and at longer focal lengths there were signs of blue and yellow fringes of colour. Aberrations were brought under control by placing a tick in the Remove Chromatic Aberration box that’s found beneath the lens corrections tab in Camera Raw. All things considered and to get the best out of this lens, we’d advise shooting in raw so you have the best chance of correcting its flaws.