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.