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Last week, Panasonic announced the Lumix S 20mm F2.5, a small, full-frame prime for L-mount. We’ve had the chance to take it out for a few shoots to produce a sample gallery and to see how it performs in various conditions.

Hands-on impressions

Mitchell Clark

The Lumix S 20mm F2.5 feels relatively well-constructed, with pleasing tactile controls. Of course, its main focus is being compact and lightweight, a task which it gets full marks for. It only adds a bit of depth compared to my camera’s grip, and I found it very easy to slip into a bag to bring along for everyday outings.

Vingetting is well-controlled; there’s a bit at F2.5 through to F4, but it’s not enough to be distracting. It’s around what we’d expect given that this lens is focused on being small and lightweight, while not being super fast. I did, however, typically have to stop down a bit further to get super-sharp edges and corners, as they’re a bit soft below around F5.6.

To achieve this size, Panasonic – like essentially all other companies making lenses for modern mirrorless systems – has made use of software geometric correction. Without it, there’s substantial pincushion distortion, and, occasionally, darkness in the corners.

The lens is susceptible to some flare under very harsh conditions. On one of the afternoons I was shooting with it, I found a few of my photos had some large purple flares when I was shooting in the general direction of the afternoon sun. In the shots where I was deliberately trying to produce sunstars, I also got a lot of ghosting. This wasn’t too much of an issue in my testing, but if you frequently find yourself shooting in the brightest of light, you may want to consider picking up a lens hood, as it doesn’t come with one.

Mitchell Clark

The lens otherwise behaved quite well in the sun; in shots where it was fully within the frame, it did a very good job of retaining contrast.

Using the lens with the S1RII and original S1R, I never felt like its motors were the bottleneck for autofocus performance. It was very responsive, and could snap from its closest focusing distance – a respectable 0.18m (7.1″) – to objects far away very quickly. I’ve also tested a lot of pancake lenses with unit focus systems, and it was a nice change of pace to use one that focuses internally instead.

Overall, I felt this lens is a nice addition to Panasonic’s lineup, especially for ultrawide shooters. While there are a few technical drawbacks with a lens this small, I was overall quite pleased with the images I got out of it. If you’re the type of person who prefers this field of view for everyday shooting, or a videographer who wants to be able to film themselves, it’s an easy option to carry around, as long as you pair it with the right body.

Sample gallery

Please do not reproduce any of these images on a website or any newsletter/magazine without prior permission (see our copyright page). We make the originals available for private users to download to their own machines for personal examination or printing; we do so in good faith, so please don’t abuse it. 

Thanks to Panasonic for the loan of an S1RII to shoot this gallery. All images were processed using our standard lens workflow in Capture One, with the manufacturer’s distortion correction applied but no correction of vignetting. The profile corrects a large amount of barrel distortion, and we’d consider it an essential part of the lens’s optical design.

Panasonic

Panasonic Lumix S 20mm F2.5

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The Canon EOS R8 II is the latest camera to keep size down by adopting an electronic first curtain shutter design. This isn’t the same thing as full electronic shutter and it has very few downsides, so here’s how it works and what those downsides are.

Perhaps an easier way to understand EFCS is to think of it as Mechanical Second Curtain Shutter. The exposure is started electronically but a normal mechanical shutter then comes down to end the exposure, meaning that, unlike full electronic shutter, you can end your exposure very quickly, rather than being limited by readout speed of your sensor.

This means EFCS doesn’t have the significant rolling shutter artifacts (banding under flickering light and distorted moving subjects) that all but the fastest sensors can exhibit. The fast end to the exposure also means it can usually sync with flashes up to the same speed as a fully mechanical focal plane shutter.

In fact, it can have a benefit over full mechanical shutters, in one regard: because there’s no physical shutter snapping open at the start of the exposure, it eliminates a key source of vibration that can cause shutter shock. Some cameras with full mechanical shutters switch across to their EFCS mode within certain shutter ranges for exactly this reason.

This is the reason we’ve seen an increasing number of cameras, particularly the ones where the manufacturer has focused on downsizing and on cost reduction. In most instances, EFCS lets you use a smaller, mechanically simpler mechanism, with very little disadvantage.

The downside

It’s not entirely without downsides, though. At very high shutter speeds, where the period during which the shutter is closing makes up a significant proportion of the exposure, you can experience bokeh truncation: part of the bokeh pattern getting chopped off.

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This happens because the physical shutter used to end the exposure sits some distance in front of the sensor, so light can creep around the edge of the shutter blades as it closes. But the electronic first curtain (progressively turning the rows of the sensor on to start the exposure) doesn’t have that gap, so the start of the exposure didn’t have that light bleeding around the edge of the ‘shutter,’ giving one side of the bokeh a hard cut-off. This results in out-of-focus regions that aren’t as blurred and may not have such attractive bokeh.

However, this only becomes visible at very high shutter speeds when using lenses with fast enough apertures to significantly blur the background.

The ‘hard-edged’ nature of the electronic initiation of the exposure also means that any banding effect (from the fast flicker of LED advertising displays or high-speed sync flash) can end up being better defined and more distracting than with a fully mechanical shutter, again because light creeping around the gap between physical shutter blades and the sensor surface can soften it somewhat.

For the vast majority of situations though, including flash sync, electronic first curtain (/mechanical second curtain) shutter, is every bit as good as full mechanical shutter.