Panasonic's original beloved MFT pancake — the Mark I of the 40mm equiv f/1.7 pancake prime.
The Panasonic Lumix G 20mm f/1.7 ASPH. is a compact pancake prime for Micro Four Thirds cameras and one of the most popular fast primes in the MFT ecosystem, providing 40mm equivalent at f/1.7 in a near-flat profile. ASPH. indicates an aspherical element. MFT mount.
f/1.7 maximum aperture. 20mm focal length (40mm equivalent on MFT). ASPH. (aspherical element). At approximately 87g. 46mm filter thread. Micro Four Thirds mount. Contrast-detect AF.
The 20mm f/1.7's combination of f/1.7 speed, 40mm-equivalent normal field of view, and near-pancake dimensions makes it one of the most versatile compact primes in any mirrorless system. The contrast-detect AF is slower than the later DFD (Depth-from-Defocus) phase-detect system but adequate for street and travel use. A first and second version exist with minor cosmetic differences.
On the used market the Panasonic Lumix G 20mm f/1.7 ASPH. is a sought-after compact MFT prime. Condition checks: MFT mount contacts, AF response (contrast detect — slower than phase detect), 46mm front element for marks, aperture blade smoothness at f/1.7.