The Tamron 135 mm f/2.5 Close Focus is a medium telephoto lens from the late seventies, belonging to Tamron’s versatile Adaptall-2 line. It’s optical design with four lenses in four groups is similar to Minolta’s legendary MD-I 135 mm f/2.8.
The Tamron’s proximity to the Minolta does not end with the optics, though: Weight and size are also very close with the Tamron being a rough 0.1 kg lighter, having the same diameter and being only 3 mm longer. The focus throw is much shorter, though: While the MD-I offers around 270° of travel from close focus to infinity, it’s only about 150° on the Tamron. Like the Minolta, the lens features an integrated, short lens hood and handles well on a NEX-5T. The effective focal length of 206 mm on APS-C cameras make the 135 mm f/2.5 a fast, versatile tele with more than decent performance.
Fun fact: In some comparison shots, the focal length of the Tamron seemed to be a little different from that of the Minolta MD-I 135 mm f/2.8 mentioned above. A quick measurement showed that it is indeed a considerable 3.2% (= 4.3 mm) shorter.
For further details on the lens, have a look at it’s adaptall-2.org page.
Condition of my copy
Optics: Good. Minor cleaning marks in the coating and a light haze on the backside of the front element. Four ultra fine fungus-like hairs across the second element. Nearly no visible dust inside.
Mechanics: Very good. Uniform and smooth focus with a tiny bit of rotational play in the focus ring. Aperture clean and fast.
Exterior: Very good. Almost like new, except for minimal signs of use at the mount.
Optical performance on NEX-5N / 5T
The lens shows acceptable sharpness wide open with slightly soft corners and minimal haze. Some purple fringing is visible, though. At f/4 haze and fringing disappear. While the corner sharpness improves markedly, the center only gains in contrast, leading to a more even performance across the frame. Stopping down to f/5.6 results in the expected bump in resolution and pushes the sharpness to good levels. At f/8, it further improves to very good. Diffraction becomes apparent at f/11, visibly softens f/16 and mushes f/22.
The CAs are asymmetric on my copy of the lens, with the right side being hit much harder than the left. Overall, a small green/magenta glow can be spotted at f/2.5. The CAs shrink up to f/8 and grow again when stopping down further, but stay small. A very good performance.
Vignetting is about 3/4 of a stop at f/2.5 and gone by f/4. The lens exhibits a very small pincushion distortion of +0.2% and the effective T-stop at f/2.5 is T2.9 (-0.4 EV), which is okay.
In conclusion, the Tamron 135 mm f/2.5 shows a more than respectable performance for a third party medium tele. While it shares many characteristics with the Minolta MD-I 135 mm f/2.8, it does not quite reach the Minolta’s performance up to (including) f/4. After that, there’s only a tiny bit of difference in the corners, where the Minolta shows an impressive crispness and the Tamron is “only” very good. Concerning chromatic aberrations, both lenses perform very, very similar with a minimal edge for the Tamron. And this isn’t surprising considering the similarities in their design. All considered, I wouldn’t hesitate to recommend the slightly lighter and faster Tamron to anybody seeking a manual focus 135 mm. The only real downside: It’s typically more than twice as expensive as the Minolta and much less common on the used market.
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(Cropped areas marked in orange)