Review: Tamron 20mm, 24mm and 35mm f/2.8 1:2 lenses
First off, we'll admit we're a little late to the table when it comes to reviewing Tamron's 20mm, 24mm and 35mm f/2.8 prime lenses for Sony E-Mount full-frame mirrorless cameras. But although they were released at the back-end of last year, there's still nothing quite like them on the market – they're relatively cheap, very lightweight, and importantly, super sharp where it counts.
All three lenses weigh less than 250g, and all use the same 67mm filter thread. Build-wise they carry the sleek, minimalist look of lenses like the Zeiss Batis range, but with a much more plasticky feel – not that there's anything wrong with that though.
All three lenses have metal mounts and rubberised focus rings that are easy to grip with minimal resistance, and Tamron says they are weatherproofed – although beyond a small rubber gasket it's difficult to know for sure.
The three lenses also come with lens hoods, with the 20mm getting a petal-style hood (owing to the wide field of view) and the 35mm a slightly funky looking square hood.
At such a compact size, the lenses pair beautifully to Sony's full-frame mirrorless cameras like the Sony A7III and A7C, which I tested these with. They all fit really nicely in a camera-bag or pocket too, making them very versatile as carry-everywhere lenses.
The three lenses aren't the speediest autofocusers, and despite Tamron's 'Optimised Silent Drive' autofocussing motors, do make a little noise when hunting for focus. Fortunately it's not overly distracting, and doesn't sound during video recording.
We probably take it for granted how quick autofocus has become, and the lack of fast AF in the Tamron lenses is likely down to the fact that while the physical length of the lenses remains fixed, the internal barrel is quite deeply recessed at long focus settings. To travel from one end to the other (say when focussing from short to far) requires the elements to move a significant distance, which does seem to also take a while. But that said, once focus is acquired, the lenses do hold it very well.
When it comes to manual focus, its is non linear, which means changes to the focus distance are dependant on the speed with which the focus ring is turned. The trio of lenses are focus by wire too, which can occasionally mean there's a little lag – but in most manual focus settings this shouldn't be an issue.
With a minimum focusing distance of 11cm, 12cm and 15cm for the 20mm, 24mm and 35mm lenses, respectively, the three lenses reach a magnification of 1:2 (hence the name) which is unusual for lenses as wide as these three.
The Tamron's are probably not the first you would reach for if you were looking for a dedicated macro lens, but their close focussing ability is a nice feature to have – and the lenses are really sharp too, with central sharpness very good wide open, and anywhere from about f/4 to f/11 (depending on the lens) delivering excellent results on all three.
The lenses also manage flare well and ghosting is almost non-existent. Even with the sun in the frame, or edge of the frame, contrast remains high.
Chromatic aberration is controlled well, however vignetting is pretty substantial, especially wide open.
The 20mm and 24mm also have some pretty significant distortion as you might expect, but the 35mm manages it quite well. Of course vignetting and distortion are pretty quickly corrected in post, so this is an easy fix.
It's probably most relevant to the 35mm focal length (a popular choice for environmental portraits), but bokeh is pleasant, with smooth and unobtrusive bokeh balls and out of focus areas rendered nicely.
There's a lot of choice for prime lenses for Sony's E-mount, but at around $599 each, the Tamron 1:2 wide angle prime lenses are lightweight, well-built and excellent value for money. This makes them a nice alternative to the pricier Sony-branded alternatives, and a great option if you want a compact prime for your camera bag.