Tamron AF 70-300mm f/4-5.6 SP Di VC USD (FX) - Review / Test Report - Analysis
Lens Reviews - Nikon / Nikkor (full format)

Distortion

The Tamron lens shows a slight amount of barrel distortion at 70mm and moderate pincushion distortion towards the long end. This is typical for a lens in this class.

Move the mouse cursor over the focal length text marks below to observe the respective distortion
70 mm 135 mm 200 mm 300 mm

The chart above has a real-world size of about 120x80cm.

Vignetting

Vignetting is, of course, visibe at max. aperture but comparatively well controlled at around 1 EV. Closing the aperture by 1 f-stop solves most of the issue from a real-life perspective.

We're performing our vignetting analysis based on (uncorrected) JPEGs straight from the camera. The JPG engine of the Nikon D3x features a rather flat gradation curve, thus has a moderate contrast characteristic, resulting in comparatively low vignetting figures - the corresponding Canon figures are roughly 40% higher due to the more aggressive default contrast setting.

MTF (resolution)

The resolution characteristic is pretty good but not outstanding. The center quality is excellent at 70mm whereas the border/corner quality varies around the good to very good mark. This pattern is also valid at the longer focal lengths albeit based on slight reduced, but still very good center. It is also worth to mention that the contrast is comparatively punchy at 300mm - even at max. aperture. This is clearly a differentiator compared to other lenses in this class.

Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations

Chromatic Aberrations (CAs)

Lateral chromatic aberrations (color shadows at harsh contrast transitions) are well controlled. The average CA pixel width at the image borders stays below 1.2 pixel from 70-200mm and peaks at around 1.5px at 300mm. This isn't really field-relevant. In addition lateral CAs can easily be corrected in software or by the camera itself (most modern Nikon DSLRs remove CAs on-the-fly if you shoot JPGs).




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