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Lens review

Tamron 17-35 mm f/2.8-4 Di OSD

18 February 2019
Maciej Latałło

3. Build quality

The following chart presents a comparison between basic parameters of the tested lens and other 17–35 mm f/2.8–4.0 devices. You can notice at once that all these instruments constitute a tight group when it comes to physical dimensions and weight. What’s interesting, the newest Tamron hardly impresses with the number of optical elements – the much older Sigma has more of them.

In the photo below the Tamron 17–35 mm f/2.8–4 Di OSD is positioned between two full frame Canons: the EF 35 mm f/2.0 IS USM and the EF 50 mm f/1.4 USM.

Tamron 17-35 mm f/2.8-4 Di OSD - Build quality

The tested lens starts with a metal mount which surrounds contacts and a black, nicely matted and ribbed inner tube. Inside the tube you can find a rear element, almost 25 mm in diameter. That element moves: at the 17 mm focal length it is situated on the same level as the mount, when you pass to the maximum aperture it hides inside about 2 cm deep, revealing the rest of the inner tube and a plate with a lot of electronic parts. It means you can’t speak about perfect blackening and sealing of the lens.

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Tamron 17-35 mm f/2.8-4 Di OSD - Build quality

The first part of the proper barrel of the lens is a rubber basket joined with a silver, metal ring which doesn’t move. That ring turns into a smooth, black casing with a white marking point, making an alignment with a camera easier.

On the next, smooth ring you can find the producer’s logo, the name, and parameters of the lens. On its left side (looking from above) there is a focusing mode switch (AF/MF). Right next to it you see a big inscription “DESIGNED IN JAPAN” and then, in lower case, ‘MADE IN VIETNAM’, plus the filter diameter, that of 77 mm, and the model identification number, A037.

Tamron 17-35 mm f/2.8-4 Di OSD - Build quality

A zoom ring is next; it is 24 mm wide and mostly covered by rubber ribbing. On its surface you can find focal length markings at 17,20, 24, 28 and 35 mm. That ring moves smoothly and is properly damped.

Tamron 17-35 mm f/2.8-4 Di OSD - Build quality

Further on you see a smooth, immobile part of the casing which turns into a manual focus ring. That ring , completely covered by rubber ribs, is 15 mm wide. In the AF mode you can turn it but you feel a lot of resistance and hear a whirr of interlocked mechanism. In the MF mode it moves very easily and without any noises but, to be honest, we found its work a bit too loose. Anyway the ring is hardly useful because, with its narrow working range, amounting to just 80 degrees, it doesn’t ensure you a high precision of your settings.

Tamron 17-35 mm f/2.8-4 Di OSD - Build quality

The front element system is movable, extending on an uniform tube when you change the focal length. It sticks out the most at the 17 mm focal length and it hides the deepest near 26 mm and then it starts to extend again but not as distinctly as at 17 mm. The front element itself is 45 mm in diameter, slightly convex, surrounded by a non-rotating filter thread, 77 mm in diameter, and a hood mount.

Tamron 17-35 mm f/2.8-4 Di OSD - Build quality

When it comes to optical construction you deal here with 15 elements positioned in 10 groups. Among them you can find two aspherical and four low dispersion elements. Inside there is also an aperture with seven diaphragm blades which can be closed down to a value ranging from f/16 to f/22 at the maximum, depending on the aperture you employ.

Tamron also used here BBAR (Broad-Band Anti-Reflection) coating technology and a fluorine coating on the front element which is supposed to protect from dust, dirt and fingerprints. There are seals throughout the lens to resist moisture and thus make shooting possible even in poor weather conditions.

Buyers get just two caps in the box with the lens.

Tamron 17-35 mm f/2.8-4 Di OSD - Build quality