Tamron AF 90mm f/2.8 SP Di macro (Nikon mount) - Review / Lab Test Report - Analysis
Lens Reviews - Nikon / Nikkor (APS-C)
Article Index
Introduction
Analysis

Distortion

As to be expected from a fix-focal lens and especially from a macro lens the level of distortion is negligible.

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

Vignetting

The Tamron is a full format lens and enjoys a sweet spot advantage on the Nikon D200 (APS-C DSLR). At f/2.8 the lens exhibits only marginal vignetting (0.38EV) which is hardly field relevant. From f/4 & up the issue is absolutely negligible.

MTF (resolution)

Typical for most macro lenses the Tamron AF 90mm f/2.8 Di SP macro performed great in the MTF lab. The lens is already excellent in the center at wide-open aperture with marginally worse corners. The lens reaches its peak performance at f/5.6. Beyond f/8 diffraction is the limiting factor - a physical barrier where no smart lens design can help. Generally you should avoid stopping down beyond f/16.

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)

Similar to most other fix-focal lenses chromatic aberrations (color shadows at harsh contrast transitions) are quite low and usually nothing to worry about.

Verdict

The Tamron AF 90mm f/2.8 SP Di is a superb lens without any significant flaws and it's easily as good as the corresponding (classic) Micro-Nikkor - the resolution figures are extremely high, vignetting is marginal, CAs are low and distortions are non-existent. The build quality may be slightly inferior in comparison to the Nikkor but then the price tag is also substantially lower so the verdict can only be - HIGHLY recommended!

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