The Lumix G 20mm f/1.7 is an impressively compact prime lens that produces the 35mm focal length equivalent of 40mm when attached to a Micro Four Thirds camera. This is an interesting focal length that falls somewhere between a 35mm wideangle prime and a 50mm standard prime. This makes it a great choice for street photography, everyday snaps of people and places, and also as a lightweight travel lens. That said, the biggest selling point of the 20mm f/1.7 isn’t so much its ‘halfway house’ focal length, but rather its diminutive size. In fact, the 20mm f/1.7 is commonly referred to as a ‘pancake’ lens – at just 25mm in length and 87g in weight, it’s truly tiny.
Thankfully, it’s also a very capable and easy-to-use lens. While the lens lacks any buttons, the manual focus dial is easy to grip and rotates smoothly when engaged. Build quality impresses too, with the predominantly metal finish giving the 20mm f/1.7 a premium look and feel. Internally, the lens is constructed from seven elements in five groups, which includes two aspheric elements to reduce distortion and purple fringing on high-contrast borders.
With a maximum aperture of f/1.7 the lens can be used to create a shallow-depth-of-field effect, with the seven curved aperture blades lending an attractive look to out-of-focus areas. And of course, a maximum aperture of f/1.7 is also useful in low-light situations too. Optically the lens performs really well; the 20mm f/1.7 is pin-sharp in the centre of the frame at all apertures, including wide open. While edge sharpness at f/1.7 isn’t quite as razor sharp as the centre of the frame, stopping down to f/2.8 hugely improves things. If you’re in the market for a unobtrusive prime capable of very good results then the 20mm f/1.7 fits the bill perfectly.