The Panasonic Lumix G 20mm f/1.7 II ASPH Lens Review

The Panasonic 20mm pancake is a lens that shouldn’t exist.

When we think about optically superb lenses, this tiny and unassuming lens is probably not the first thing that jumps to mind. Instead, a more sensible candidate would be the incredible Olympus 75mm f/1.8, the massive Voigtlander 17.5mm f/0.95 or the spectacular Leica Nocticron 42.5mm f/1.2. Aside from their impeccable optical credentials, all these lenses bring something else to the table: a solid, tank-like heft and a considerably large size.

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You see, there’s nothing like size and heft to convey quality in an object. Size draws attention, and weight screams high-end. Even in things like lenses, where small size and light weight are considered features, the top performers in every category always manage to eschew them in favor of the more traditional, more instinctive appeal of an imposing exterior.

And then there’s this small pancake lens, with its feather-like weight and impossibly slim size. Just by looking at it, you would assume it’s little more than a toy-lens, something to use for fun or merely to bide your time until you can buy a real, serious lens.

You could be forgiven for assuming that, but that doesn’t mean you wouldn’t be spectacularly, colossally wrong.

Indeed, the Panasonic Lumix G 20mm f/1.7 II ASPH pancake lens has much more in common with those great lenses than it does with lesser pieces of glass. Its image quality is stellar, it’s sharp even wide open and its rendering is pleasant and natural. As far as the images this lens produces, there’s little in them to suggest they were taken with anything other than a top-notch optical instrument.

With such an impressive performance in so small a package — not to mention affordable — the Panasonic 20mm defies conventional design language in such a way that it’s almost difficult to believe a lens like this even exists. Fortunately for us, that doesn’t make it any less real.

Let’s take a closer look at everything it has to offer.

Build quality

Note: This entire review refers to the Mark II redesign of this lens, which was introduced in 2013 and replaced the original 20mm pancake lens from 2011. The differences between the two are mostly related to build quality, with the new version sporting a black metal body instead of the gray resin body of its predecessor. Optically, both lenses remain largely identical, with performance being equal between the two.

Upon picking it up, the most impressive thing about this Panasonic pancake is its incredibly light weight. At a mere 87g / 3.07oz (excluding front and rear lens caps), this is one of the lightest lenses available for any camera system (other than body-cap type lenses, obviously).

A feather-like weight like this is usually achieved by using lighter materials in the lens’s construction. In this case, however, Panasonic still managed to give this 20mm lens a metal body and a metal mount while keeping the weight down, which is definitely an impressive achievement.

The metal build gives the lens a nice, solid feel in the hand, which is rather surprising for a lens in this price range and with these characteristics — a pancake design, which emphasizes lightness and compactness, is poised to use lighter materials than, for example, a massive tele-zoom.

Thanks to this solid build, the pancake is tough enough to withstand the rigors of everyday use without breaking a sweat. While we wouldn’t recommend dropping it on a regular basis, there’s nothing in the lens that appears overly fragile.

The lens is not weather-sealed though, so dropping it in a puddle of water is probably not a good idea. That said, it should be able to handle drizzle or very light rain, but try it only at your own risk.

The Panasonic 20mm doesn’t come with a lens hood, nor does it need one. One of the biggest strengths of this lens is its slim profile, so it’s highly recommended to avoid using a lens hood entirely. Besides, the use of modern coatings and aspherical elements makes it largely unnecessary anyway. In fact, Panasonic doesn’t even make a hood for this lens, although it’s possible to buy 3rd-party ones that attach to the filter thread.

The included lens cap is a standard plastic cap with the release buttons placed at the sides. This system works very well for a lens like this, helping it keep a slim profile even when the lens cap is on.

Ergonomics

The design of the Panasonic 20mm is almost spartan in its simplicity. Other than the 46mm filter thread on the front and the textured focusing ring, there’s not much else going on here.

The focusing ring is made of hardened plastic, unlike the rubberized focusing rings found in some higher-end lenses, like the excellent Leica Summilux 25mm f/1.4. In practice, though, the more pleasant feeling of a rubber ring is little more than a nice design touch, with the plastic here providing plenty of feedback and grip to make focusing easy and precise.

The lens uses a “focus by wire” system, which means the focusing ring is not mechanically linked to the focusing motor, and therefore the actual motor is electronically operated.As such, the resistance you feel when turning the ring is always the same. This resistance is noticeably greater than that of many other MFT lenses, and may be slightly uncomfortable to use for some people. It also requires a substantial amount of throw to advance through the focusing range, meaning that, while focusing can be very precise, it takes a while to switch from infinity to the lens’s closest focusing distance, and vice versa.

Moreover, there’s no depth-of-field scale on the lens to aid with manual focusing, and it also lacks hard stops at both ends of the focusing range.

Other than that, the ergonomics of the Panasonic 20mm lens are excellent. Its extremely light weight and simple, no-nonsense design mean it’s always easy to use, regardless of the size of your camera body. There are no customizable function buttons to mess with, or retractable hoods to keep track of. All you need is one hand to operate the focusing ring, should you choose to focus manually. And, as we’re about to see now, there’s a very good reason to do that with this lens.

Autofocus

Without a doubt, autofocus is the worst-performing aspect of the Panasonic 20mm pancake lens. There’s some debate as to whether the situation is particularly bad on Olympus bodies, but even with Panasonic cameras, this lens can’t hold a candle to the vast majority of lenses in the MFT ecosystem.

In good light, changing focus from infinity to the closest focusing distance of 20cm can take up to one second. That’s an eternity compared to the nearly instant AF found in many other lenses these days. And in poor lighting conditions the pancake fares even worse, hunting quite a bit before finally achieving focus.

What’s even worse, focusing accuracy is nothing to write home about, either. While the lens usually achieves focus on the intended spot, every now and then it seems to get confused, missing focus entirely. Coupled with its poor focusing speed, this can make the whole experience rather frustrating at times.

Since one of the greatest strengths of the MFT system is its blazing-fast autofocus, the poor AF performance of this Panasonic lens is even more disappointing. Using this lens can be problematic when shooting moving subjects, which makes the lens harder to use for things like street photography, taking images of children, sports, etc.

Finally and unlike many other lenses, focusing with the Panasonic 20mm is not silent. The focusing motor emits a barely audible humming sound when it’s activated, which may become noticeable in recorded video. For that reason, we recommend switching to MF mode when shooting video.

The Panasonic 20mm lens was refreshed with a Mark II redesign in 2013. By then, the AF woes of this lens had already been widely documented by many MFT shooters, making the fact that it didn’t get fixed all the more baffling. A missed opportunity that surely would have taken an already excellent lens and elevated it to cult status.

Image quality

Don’t let its small size fool you: when it comes to image quality, this pancake lens punches well above its weight.

Images out of the Panasonic 20mm lens are clinically sharp, contrasty and clean, with rich colors and a very pleasant rendering overall. While it doesn’t reach the optical heights of some of the more exotic pieces of glass for the system, it’s certainly a top-shelf performer in its own right.

Let’s take a look at some of its characteristics in a bit more detail.

Sharpness

Sharpness is where this small lens starts to betray its unassuming looks. Images are sharp in the center right from the maximum aperture of f/1.7, with the corners being slightly softer but still perfectly usable. Stopping the lens down a bit improves sharpness even more, bringing the corners up to excellent levels by f/2.8. The center remains tack sharp down to f/8, and as with most MFT lenses, overall sharpness peaks at about f/4 or f/5.6. From f/8 and down to the lens’s minimum aperture of f/16, sharpness quickly begins to suffer as a result of diffraction.

What this means in practice is that sharpness is not a factor when using this lens. With lesser lenses, you often need to stop them down to avoid softness, only shooting wide open when it’s absolutely necessary to avoid raising your ISO setting. Not so with this lens. You can shoot the Panasonic 20mm wide open in good light if you want, and your images will still be sharp enough for any kind of picture. Such an excellent sharpness level throughout the aperture range provides plenty of creative freedom to play with depth of field, as we’ll see in a moment.

Bokeh and depth of field

Bokeh is a term that refers to the aesthetic quality of the out of focus areas in an image, not the extent to which they’re out of focus. Some factors that typically affect the bokeh of a lens are the number and grouping of its optical elements, the number of aperture blades it has, and whether those blades are rounded.

The Panasonic 20mm lens renders a nice bokeh, a bit nervous but pleasing, with objects smoothly transitioning between the in-focus and out-of-focus areas.

The diaphragm of the lens has seven circular blades, which helps keep highlights round and nice in the center of the frame, although they do take a bit of a cat’s eye shape towards the edges.

The relatively short focal distance — 40mm in Full Frame terminology — means subject isolation is harder to achieve than with longer lenses. Still, thanks to its fast aperture, the Panasonic 20mm is perfectly capable of isolating a subject, particularly when focusing close, where depth of field is only a few centimeters.

Color rendition and contrast

In the era of VSCO film and in-camera film emulation filters, most people are perfectly happy with applying a preset or selecting a filter and not doing much in the way of post-processing beyond that. As a result, native color rendition, contrast and rendering have become slightly less important than they used to be.

Color rendition out of the Panasonic 20mm lens is excellent, with very pleasing skin tones and contrast right out of camera. With just the slightest bit of post production, images from this lens truly shine.

This Panasonic lens has a more neutral color rendering than the Leica Summilux 25mm lens, but not as neutral as that of many Olympus lenses. In a way, it strikes a nice middle-point between the painterly look of the Leica lenses for the system and the more sterile look of the Olympus offerings.

All this is of course entirely subjective, as different people will prefer different looks.

Whatever you prefer though, keep in mind that any of today’s MFT lenses will produce excellent images that are adjustable in post production to achieve your desired look. So, while color rendition and contrast are technically properties of the lens, they probably shouldn’t be a deciding factor when making a purchase.

High-ISO banding

There’s a widely reported issue with the Panasonic 20mm lens, and it’s banding at high-ISO settings. It’s been speculated that the issue only affects some camera models (most notably, the original Olympus OM-D E-M5). It’s also been said that it depends on each individual copy of the lens, hinting at a possible manufacturing defect.

For what it’s worth, banding is clearly present on an Olympus OM-D E-M10 at ISO settings above 800. It’s most apparent when trying to pull detail from the shadows, but it’s clearly present at normal exposure values, too.

So far, there’s no official fix for the issue and we can’t confirm whether your particular camera and lens combination will be affected, so if this is a deal breaker for you, be sure to check before you buy.

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Vignetting

Vignetting is light falloff that occurs in the corners of an image, particularly at large apertures.

Vignetting is noticeable wide open, but it’s not as severe as in the Leica 25mm lens. It’s basically gone by f/2.8.

Vignetting isn’t always an unwanted property though, and in fact many people enjoy the artistic effect it creates in some images. That said, should you want to eliminate it completely, it’s easily corrected in post production.

Chromatic aberration and fringing

Chromatic aberration and color fringing refer to the lens’ ability to capture a full range of colors of visible light at the same point. Heavy chromatic aberration typically appears in the form of purple or green fringing around the more contrasty borders of an image.

As is usually the case with fast lenses, the Panasonic 20mm presents some purple fringing wide open. Panasonic cameras correct for CA automatically, but Olympus cameras do not, so if you own an Olympus camera you’ll need to remove it in post production. Usually all it takes is clicking one box and you’re good to go. Alternatively, stopping the lens down a bit is usually enough to eliminate all but the most severe color fringing.

Ghosting and flare

Lens flare may occur when a bright light source is caught in the angle of view of the lens, in such a way that its light rays hit the front element of the lens directly. Those rays may then bounce off other elements or even the sensor itself, producing several artifacts along their path. Lens flare usually presents itself in the form of severe haze and a pronounced loss of contrast across the entire frame.

The Panasonic 20mm lens features two aspherical elements in its construction, which are designed to increase protection against flare. Indeed, flare resistance is excellent with this lens, but it’s always best to remain vigilant.

When it does appear, though, it can be nasty.

That said, unless you manage to catch the sun or a similarly bright light source just outside your frame, flare is usually nonexistent, which is why this lens doesn’t really require a lens hood.

Distortion

Both Panasonic and Olympus camera bodies automatically correct distortion with Olympus and Panasonic lenses, so any distortion will be gone before you even open your photo-editing application of choice.

Even then, some residual distortion may appear on occasion in the final images with poorly corrected lenses. With the Panasonic 20mm, though, distortion is extremely well controlled, barely requiring any adjustments at all in post production.

Real world usage and image samples

Using this lens is usually a very pleasant experience, but one must be aware of its limitations. Its small size and light weight make it ideally suited for traveling, walking or any other activity where you’ll need to carry your camera for hours. Similarly, its slow AF performance makes it less suitable for photographing moving subjects, so street photography, children, sports and the like are areas where this lens struggles to keep up with the action.

The 40mm-equivalent field of view of this lens is considered standard, and is halfway between the classic 35mm and 50mm focal lengths. This standard length is very versatile and will allow you to capture many different types of shots. If you can’t quite decide whether you prefer to shoot with a 35mm or a 50mm lens, you may feel right at home with this pancake lens.

Its pleasing color rendering and nice skin tones right out of camera make this a very good lens for taking pictures of people. Environmental portraits, where photographers try to show a bit more of the scene along with their subjects, is one area where this lens truly shines.

Street photography is doable with this lens, but it’s far from ideal. The slow AF performance wouldn’t be such a big issue if the MF implementation had been better, but without a depth of field scale to aid in manual focusing, it’s extremely difficult to keep track of the in-focus area when you’re out there shooting.

You can get away with taking pictures of slow-moving subjects, but anything beyond that will be better accomplished with a different lens. Luckily, there’s no shortage of such lenses in the MFT system to choose from.

Being a standard length, distortion is not usually a problem unless subjects are extremely close. Similarly, distortion in architectural shots is very well controlled, often requiring very little effort in post production to ensure vertical lines remain straight.

Landscape photography is very good with the Panasonic 20mm thanks to its excellent sharpness across the frame when stopped down a bit. To make up for the not-so-wide angle of view of the lens, you can take several images in succession and then stitch them together in post production to create super-sharp, high-resolution panoramas that will impress even the most demanding users.

Low-light photography is a bit of a mixed bag with this Panasonic pancake. On one hand, its fast f/1.7 aperture helps shoot in low light without raising your ISO setting. On the other hand, though, once you raise it, banding becomes apparent, severely degrading image quality across the frame in a way that is not salvageable in post production. That is a very unfortunate issue that limits the real-world usability of this lens from good to moderate lighting conditions, unless you have a sturdy tripod with you.

On the not-so-good areas, the lack of weather sealing limits the usability of this lens to good to mild weather conditions. A light drizzle shouldn’t be a problem, but we wouldn’t take this lens out in the rain. And of course, its poor AF performance means fast action shots or sports photography are entirely out of the question.

However, technical merits aside, the greatest asset of this lens is clearly its compact size and incredibly light weight. Coupled with one of the smaller MFT camera bodies or even an OM-D E-M10, the combination remains small and light enough to fit in most small bags and even coat pockets. That means you can take it with you almost anywhere, and never be caught without your camera. Having such an excellent optical tool with you at all times can be priceless.

Room for improvement

The Panasonic 20mm pancake is an excellent lens, but it does exhibit several flaws that Panasonic could have fixed in the Mark II redesign. Here are some of the areas where we feel the lens should perform better:

• Autofocus speed. The Panasonic 20mm is pretty slow to focus by today’s standards, even in good light. There’s no going around that. With no shortage of excellent lenses with blazing fast AF, Panasonic surely has the means to fix it.

• Manual focus implementation. The poor AF performance of this lens would be more tolerable if it had a great MF implementation. Alas, the overly stiff focusing ring, excessive throw, and lack of a distance scale and hard stops make this lens merely adequate for manual focusing, not excellent. And as Olympus has shown with their fantastic clutch-focus mechanism, it’s entirely possible to include a superb MF implementation without adding bulk to the lens.

• Weather sealing. This is admittedly a high-end feature that would probably raise the price of the lens by a few hundred dollars, but it would make it the ultimate travel and walk-around lens.

• High-ISO banding. This problem has been present since the original version of the lens was released, and it continues to be present in its current incarnation. This sadly renders the lens basically unusable for low-light photography. We don’t know if Panasonic, Olympus, or both are to blame, but fixing it is long overdue.

Alternatives

If you think the Panasonic 20mm may not be the best choice for you, here are a few great alternatives you can consider:

• The Olympus M. Zuiko 17mm f/1.8. This small jewel from Olympus is the obvious natural competitor to the Panasonic 20mm pancake. With a classic 35mm field of view and sporting an all-metal design with Olympus’s trademark clutch-focus mechanism, this lens is a really solid choice. Add to that a working depth-of-field scale and hard stops at both ends of the focusing range, and the Olympus lens will be a pretty compelling alternative for many people. Performance-wise, it’s not as sharp as the pancake wide open, but it’s still very good. The Olympus, however, runs laps around the Panasonic in both AF and MF modes, and is generally a much more snappy and responsive lens to use. Size-wise, there’s not much difference between the two, with the pancake being slimmer but the Olympus being narrower. And price-wise, the Olympus is about $100 more expensive than the Panasonic, coming in at $399 as of this review’s publication.

• The Olympus M. Zuiko 25mm f/1.8. This fantastic prime lens by Olympus is not much bigger and heavier than the Panasonic pancake, is just as fast, and sports a relatively close focal distance. Like many Olympus primes, the 25mm offers excellent image quality and a solid, if not spectacular, build quality to go along with it. In terms of AF performance, the Olympus wipes the floor with the pancake but, to be fair, almost every other modern prime would do so as well. Price-wise, both lenses cost about the same, with the Olympus coming in at $299.

• The Panasonic Leica DG Summilux 25mm f/1.4. Just like the Olympus 25mm, the Leica 25mm is an excellent performer in a relatively close focal length, making it a suitable alternative to the 20mm pancake. With a maximum aperture of f/1.4, the Leica 25mm is two-thirds of a stop faster and offers a more vivid, almost painterly rendering with excellent micro-contrast. It also has a much faster and precise AF performance. On the minus side, it is substantially larger and heavier than the pancake while being made mostly out of plastic, and it’s twice as expensive, too, coming in at $600. That said, if you require the best optical quality in a standard lens, the Leica is still the one to get, and it’s worth every penny. Check out our own review of the Leica 25mm for more information.

• The Olympus 12-40mm f/2.8 PRO zoom. If you can’t quite make primes work for you, you’ll be pleased to know Olympus also offers the outstanding series of PRO zooms. With a maximum aperture of f/2.8, they clearly won’t break any speed records, but that’s about the only bad thing one could say about them. Everything else about the PRO lenses screams quality: the all-metal build, the clutch-focus mechanism with hard stops for manual focus, the solid heft. These are optical tools built to perform well under the most demanding conditions. Check out our own review of the 12-40mm PRO zoom for more information.

Final words

The Panasonic 20mm pancake is a lens that shouldn’t exist. Judging by its size and weight, nobody would guess the amazing image quality that comes out of this wonderful piece of glass.

With its super versatile focal length, fast aperture and truly stellar IQ, this is as much lens as most people will ever need. If you appreciate the “one camera, one lens” philosophy, you could do a lot worse than going with this amazing pancake lens.

Unfortunately, there are several non-trivial issues with the Panasonic 20mm that keep it from achieving perfection. Whether those issues are deal breakers, of course, is for you to decide. In any case, it’s too bad Panasonic hasn’t bothered to fix them, because most of them would be fairly easy to solve without requiring any huge sacrifices to what makes the lens so good: its ridiculously small size and light weight.

In all honesty, it’s a bit frustrating to see a lens that is so close and yet so far from being the definitive walk-around lens — which is another reason why this lens shouldn’t exist in its current incarnation.

Admittedly, there are more exotic lenses out there, and the ever-changing technology landscape makes it easy to desire these new and flashy pieces of glass instead of this classic — and, by now, even boring — pancake lens. Despite its well-known flaws, though, the Panasonic 20mm is so good and costs so little that it’s always worth keeping around in your bag.

If the best camera is the one you have with you, this Panasonic pancake certainly has the potential to turn any MFT camera out there into the best camera you’ll ever use. The rest, as they say, is up to you.

Free Photography Guide: Download our Better than iPhone Photography guide to help you get started with you photo skills and camera basics. Along with our gear recommendations for getting started. Get it here.