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Tamron 20mm F/2.8 Di III OSD M1:2 Prime lens Review

In this last installment of our mini-series on reviewing Tamron prime lenses, we’ll be taking a look at the Tamron 20mm f/2.8 Di III OSD M1:2 lens, which is arguably the most fascinating of the three options. It is not included in the field of view of conventional zoom lenses, but it can serve as an entry point for photographers on a tight budget into the genuine ultra-wide field of view.

This does not imply that there is a significant amount of a physical difference between it and its more moderately sized relatives (the 24mm and 35mm f/2.8 lenses). You will have a difficult time distinguishing between the two of them, as was indicated in the review that came before this one. Nevertheless, this unquestionably contributes to the overall reduction of production costs.

Tamron 20mm F/2.8 Di III OSD M1:2 Prime lens Price

However, Tamron has managed to keep the price tag around a fairly low 300 USD/EUR, which is noteworthy, especially considering that it is a full-format lens. Ultra-wide lenses often have a higher price tag.

You cannot reasonably anticipate receiving quality on par with that offered by professionals for this amount of money. The chassis is constructed with polymers of mediocre quality that are mounted on a metal basis. Even though it functions well, the rubbery focus ring has a distinctly low-quality feel about it. Surprisingly, the lens contains certain seals that make it resistant to moisture; nevertheless, there is no mention of dust protection anywhere on the packaging.

Tamron 20mm F/2.8 Di III OSD M1:2 Prime lens Specs

Optical construction9 elements in 8 groups inc. 1x aspherical and 3x LD elements
Number of aperture blades7 (rounded)
min. focus distance0.11m (max. magnification 1:2)
Filter size67mm
Hoodbarrel-shaped with a frame window (bayonet mount, supplied)
Other featuresdust & moisture resistant
MountSony FE

During the focusing process, the length of the lens does not change; nevertheless, there is a tube inside the lens that moves. Due to the fact that this tube is rather deeply recessed by around 1.5 centimeters, it is not quite obvious why Tamron built the lens to be relatively lengthy. A lens hood in the shape of petals is included.

A linear extension mechanism is utilized by the AF system. The autofocus (AF) speed is on the sluggish side, but at least it doesn’t make any noise, which is typical for this sort of focusing mechanism. It is not possible to say the same thing regarding the aperture mechanism. When the shutter is fully depressed, you will be able to hear the camera opening and closing the aperture as it performs focusing operations. This again gives the air of something that was done on the cheap.

As is customary, “by-wire” operation is used for manual focusing. In this instance, the accuracy is rather satisfactory. The lens is notable for its ability to focus extremely close to the subject. It is able to focus down to an object magnification that is a maximum of 1:2. (hence the M1:2 in the lens name). It should not come as much of a surprise that an image stabilizer has not been included considering that the pricing is so low.

Sample Images

TAMRON A09 28mm