Tiny lens, huge viewing angle

The Panasonic Lumix S 20mm f/2.5 weighs just 142 grams and measures 69x41mm. It delivers a 94.5-degree field of view in an amazingly compact package.

Built tough despite the weight

The lens features dust, splash and freeze resistance with weather seals and a metal mounting plate. The front element has a fluorine coating to repel moisture.

Perfect match for Lumix S9

Panasonic designed this lens to complement the compact Lumix S9 camera body. It's part of a trio of lightweight lenses that maintain balanced proportions.

Priced at $499

The lens costs $499 in the US and £429 in the UK. That's more than the 40mm f/2 but less than the 18-40mm zoom from the same series.

Autofocus is quick and silent

A stepping motor drives internal focusing elements, so the front doesn't extend or rotate. It's extremely quiet, making it ideal for video work.

Gets incredibly close to subjects

The minimum focus distance is just 0.18 meters from the sensor. This enables serious close-up potential and makes selfies from arm's length easy.

Includes physical focus mode switch

Unlike many compact lenses, this one has an AF/MF switch on the barrel. You don't need to dig through camera menus to change focus modes.

Customizable function button included

The lens features a programmable button positioned diagonally for easy access. You can assign it to autofocus lock or Panasonic's crop zoom feature.

Center sharpness is excellent

Sharpness in the central region is superb even wide open at f/2.5. The lens delivers impressive clarity and color rendition in the middle of the frame.

Edge sharpness needs stopping down

Sharpness drops off toward edges and corners at f/2.5. You need to stop down to f/8 for good edge sharpness across the entire frame.

“Poor wide-aperture edge-sharpness”

Fast enough for low light

The f/2.5 aperture pulls in decent light for architectural interiors and night scenes. It's slightly faster than typical f/2.8 zoom lenses.

Great for vlogging and selfies

The wide field of view lets you capture yourself at arm's length while including plenty of background. The vari-angle screen on the S9 helps here.

Suppresses focus breathing for video

The lens is designed to prevent changes in field of view when you adjust focus. This makes it particularly well-suited for videography work.

Serious ghosting and flare issues

The lens is very susceptible to ghosting and flare when shooting against the light. Panasonic doesn't include a hood or sell one separately.

“Shooting against the light with no hood mounted on this lens can often give rise to the kind of result shown below.”

Buy an aftermarket hood

You can shield the lens with your hand or buy a third-party hood that screws into the 62mm filter thread. This will help control flare problems.

Versatile for many shooting styles

The lens works well for landscapes, cityscapes, architectural interiors, street photography and travel. It's surprisingly versatile for a prime lens.

Lab tests confirm sharpness pattern

Imatest results show superb central sharpness even wide open. However, corner sharpness drops steeply at larger apertures, requiring f/8 for even performance.

Minimal color fringing detected

Chromatic aberration is very well controlled at all apertures and across the whole frame. Fringing won't be visible in general shooting situations.

Four-star verdict overall

The lens earns praise for its compact build and wide perspective. However, edge sharpness issues and flare susceptibility prevent a perfect score.

“I'm mostly impressed with the Panasonic Lumix S 20mm f/2.5.”

Consider these alternatives

The Sigma 20mm f/2 offers faster aperture and metal build for $769. The Viltrox 28mm f/4.5 pancake costs just $99 but has a fixed aperture.