Tamron 18-200mm f/3.5-6.3 Di II Macro - £170/ $220
This lens made a splash when it launched, but that was in 2005, and it's the only zoom on test without image stabilisation. Getting sharp handheld shots is a challenge, with a maximum available aperture of only f/6.3 at the longest zoom length.
The Nikon-fit version originally had no internal autofocus motor, instead relying on the in-camera AF drive featured on upmarket Nikon bodies. So, there was no autofocus ability on cameras such as the D40 and D60 and subsequent bodies like the D3100 and D5100. Tamron put things right in 2008, adding a basic built-in autofocus motor.
Performance
Autofocus is a little slow, and quite shrill. Sharpness isn't great at 18mm, and drops off slightly between 35-135mm, and more so at 200mm. Distortion is more disappointing, considering the relatively modest zoom range. Barrel distortion is particularly noticeable at the 18mm focal length and, unlike with genuine Nikon lenses, auto-correction isn't available.
Sharpness
At maximum apertures, sharpness is quite lacking throughout the zoom range. At f/8 the lens fares rather better.
Lab test at f/8
Sharpness at wide angle: 1352
Sharpness at mid range: 1269
Sharpness at telephoto: 1127
Fringing
Fringes around high-contrast edges can be an issue throughout the zoom range but are most obvious in telephoto shots.
Lab test at f/8
Fringing at wide angle: 1.56
Fringing at mid range: 1.3
Fringing at telephoto: 2.02
Full image
Cropped to 100%
Distortion
Barrel distortion is pronounced at 18mm and, unlike with Nikon lenses, automatic corrections are unavailable.
Lab test at f/8
Distortion at wide angle: -4.28
Distortion at mid range: 1.25
Distortion at telephoto: 1.09
Image quality verdict
Lab data is disappointing for the Tamron 18-200mm, and our real-world results are further hampered by the lack of optical stabilisation.
Taken at 18mm (min)
At 200mm (max)
