Panasonic Lumix S 18mm F1.8 Review

The Panasonic Lumix S 18mm f1.8 is the latest in Panasonic’s line of f/1.8 prime lenses for its full-frame L-mount R-series cameras including the Panasonic Lumix S1, S1R and S5.

It has the same design and dimensions as the Panasonic Lumix S 24mm f/1.8, S 35mm f1.8, S 50mm f/1.8 and S 85mm f/1.8, as well as a similar weight and near identical centre of gravity. This means that photographers and videographers can switch seamlessly between the lenses and there shouldn’t be a great deal of rebalancing required if the camera is mounted on a gimbal.

The Lumix S 18mm f1.8 is Panasonic’s widest prime lens for its full-frame cameras but there is a wider zoom lens, the S 16-35mm f/4, which retails for close to twice the price of the prime optic. The 18mm focal length means the lens is ideal for landscape, astro and architectural photography.

The Panasonic Lumix S 18mm F1.8 will be available from October 2022 for £799.99.

Like the other Lumix S-series f/1.8 prime lenses, the Lumix S 18mm f/1.8 is weather-sealed to make it resistant to moisture and dust ingress. It’s also claimed to operate at down to -10°C.

Panasonic constructs the S 18mm f1.8 from 13 elements arranged in 12 groups. Amongst those elements there are 3 aspherical lenses, 3 ED (Extra-Low Dispersion) lenses, 1 UED (Ultra Extra-Low Dispersion) lens and 1 UHR (Ultra High Refractive Index) lens. The aspherical elements are designed to enable high image quality across the whole image while the ED elements suppress chromatic aberration.

There’s a linear autofocus motor but in manual focus mode the lens can operate in a linear or non-linear fashion depending upon the setting selected in the camera’ menu. In non-linear mode, the focus is adjusted by an amount determined by the speed of rotation of the focusing ring. In linear adjustment mode, however, the focus is adjusted by a specific amount determined by the degree of rotation of the focusing ring. It’s also possible to set the degree of focus shift in relation to the angle of rotation to from 90° to 360° in 30° increments.

A mechanism within the lens is also said to suppress focus breathing in video mode so that the framing doesn’t change with focus distance. There’s also micro-step iris control over the aperture to give smooth exposure changes.

At 340g, the Panasonic Lumix S 18mm f1.8 is 15g lighter than the Lumix S 85mm F1.8, but 30g heavier than the Lumix S 24mm f/1.8. However, these differences aren’t really noticeable when the lens is mounted a camera like the Panasonic S1R which weighs 1,016g with the battery and an SD card.

Like the other Lumix S f/1.8 primes lenses, the S 18mm f1.8 is 82mm in length and 73.6mm across its widest diameter. It also accepts 67mm filters. That means it would be easy to mistake it for one of the other f/1.8 lenses, but the focal length is shown very clearly on one side.

Panasonic has adopted the same design for the Lumix S 18mm f1.8 as with its other f/1.8 lenses, which means that there’s just one ring around the barrel. That’s for focusing manually and it can’t be used for other things like adjusting the exposure compensation or setting the aperture when the autofocus system is engaged.

The broad manual focus ring sits towards the front element end of the barrel and occupies about half its length. As usual, it has a ribbed, rubbery coating that ensures a good grip. The ring’s movement is very smooth with just the right level of effort required to turn it, giving a very high-quality feel.

As now seems standard, there are no physical end points to the rotation of the focus ring. However, as soon as the ring is turned, a focus distance scale appears in the camera’s viewfinder or on the rear screen. And if ‘MF Assist’ is activated in the camera’s menu, the area under the selected AF point enlarges to make the details clearer. Panasonic’s S-series camera have a menu option to specify whether the magnified area takes up the whole screen or if it shows as a ‘picture-in-picture’. I like to use the picture-in-picture display because it enables you to keep an eye on the composition.

Provided that ‘AF + MF’ is activated in the camera’s menu and the shutter release is half-pressed, the focus ring can be used to adjust the focus in autofocus mode. That can be handy on occasion, for example when the subject is close to the 18cm closest focusing distance.

The only switch on the lens is for swapping between manual and automatic focusing.

Overall, the lens feel built to a good standard.

I tested the Panasonic S 18mm F1.8 on the 47Mp Panasonic Lumix S1R, the highest-resolution camera in Panasonic’s line-up. This gives plenty of scope to assess the lens’ ability to capture sharp detail and it passes the test with very fine details being rendered well even when the aperture is wide open. That said, the very best results are achieved when the aperture is in the range f/2.8-f/8 and the impact of diffraction becomes apparent at f/16.

As you’d expect, there’s some fall-off in sharpness across the frame, but it’s impressively minor and when the aperture is closed to f/4, the corners look very good indeed.

Using the in-camera corrections does a good job of eliminating most of the vignetting at the wider apertures, so it’s not an issue for real-world photography. It’s negligible at f/2.8 and gone by f/4.

Curvilinear distortion is also handled extremely well so that straight lines look straight, even towards the edges of the frame.

Even with a short focal length, shooting at f/1.8 with the subject quite close means that the background is thrown out of focus and the subject is isolated. The Lumix S 18mm f/1.8 delivers attractive bokeh with just a suggestion of the soap bubble effect around some small highlights.

Checking through my images with high contrast edges reveals only a few limited examples of chromatic aberration, so it’s not a significant concern. Similarly, flare is also controlled well and the supplied petal-shaped lens hood does a good job of shading the front element from side-light.

Panasonic has plumped contrast detection focusing for its cameras and paired with the company’s (Depth From Defocus) technology, it usually ensures that the subject is brought into focus quickly. The only time the camera and lens seems to struggle is when the subject is around the closest focusing point, but even then, it’s usually possible get it in focus without having to switch to manual focusing – although the full-time MF override option is handy on occasion.

The focusing system is silent and there’s no sign of focus breathing.

Follow the link to browse and download full-resolution images shot with the Panasonic Lumix S 18mm F1.8 on the Panasonic S1R.
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The build, handling and design of the Panasonic Lumix S 18mm f/1.8 is predetermined by Panasonic’s earlier f/1.8 lenses as it’s intended to fit in with them. And it does so very effectively, but it would be nice if the manual focus ring were customisable and perhaps there was a focus limiter switch and an aperture ring. Those minor issues aside, the Panasonic Lumix S 18mm f/1.8 is an excellent addition to Panasonic’s L-mount line-up. It delivers very high-quality results and there’s no need to worry about restricting yourself rigidly to a specific aperture value or avoiding back-lit subjects.