Panasonic Leica DG Vario-Summilux 25-50mm F1.7 Asph Hands-on Review

The Panasonic Leica DG Vario-Summilux 25-50mm F1.7 Asph. is a premium zoom lens that’s designed for use on Panasonic’s Lumix G-series cameras such as the Panasonic G9 and Panasonic GH5 Mark II. This means that it has the Micro Four Thirds mount and it can also be used on Olympus cameras such as the Olympus OM-D E-M1 Mark III.

A focal length of 25-50mm is unusual, but on a Micro Four Thirds camera it translates to an effective focal length of 50-100mm in full-frame terms. That makes it a short telephoto lens. It’s also the first telephoto lens to feature a constant aperture of F/1.7. This aperture combined with the focal length range could make the Leica DG Vario-Summilux 25-50mm F1.7 Asph attractive for portrait photography, but it’s suited to a wide range of uses.

It’s likely that the Leica DG Vario-Summilux 25-50mm F1.7 Asph will be partnered with the Leica DG Vario-Summilux 10-25mm F1.7 Asph, which has an effective focal length range of 20-50mm.

Panasonic’s engineers have constructed the Leica DG Vario-Summilux 25-50mm F1.7 Asph from 16 elements arranged in 11 groups. Amongst these elements there’s an aspherical element to maintain sharpness into the corners of the frame and three ED (extra-low dispersion) elements to suppress chromatic aberrations.

Towards the end of the barrel, there’s an aperture ring with markings running from f/1.7 to f/16 in 1/3EV steps. Unusually, this is a clickless ring, which is great for video,  but there’s no option to make it click. The aperture control uses a micro-step drive system which enables smooth exposure adjustments when zooming or panning.

In addition, the Leica DG Vario-Summilux 25-50mm F1.7 Asph’s focusing ring has a clutch mechanism that enables it to be switched quickly and easily between manual and automatic focusing.

When the option is available in the camera’s menu, it’s possible  to switch the lens between linear and non-linear focusing.

At the 25mm end of the lens, the closest focusing distance is 28cm while at the 50mm end, it’s 31cm. The maximum reproduction ratio is 0.42x (in 35mm camera terms).

As you’d expect with a high-end lens, the Panasonic Leica DG Vario-Summilux 25-50mm F1.7 Asph has seals to keep moisture and dust outside of its barrel.

Although they have Four Third type sensors, the Panasonic G9 and GH5 Mark II are quite large and the Leica DG Vario-Summilux 25-50mm F1.7 Asph looks well matched to them.

With a maximum diameter of 87.6mm and extending 127.6mm from the lens mount, the Leica DG Vario-Summilux 25-50mm F1.7 Asph. is a substantial-looking optic, but it weighs only 654g, which feels pretty good on the GH5 Mark II. Nevertheless, paired with the GH5 II, it’s a combination that more closely resembles a full-frame DSLR with a 24-70mm f/2.8 than a Micro Four Thirds mirrorless camera.

I like aperture rings on lenses, but I’m used to click stops for photography and de-clicked lenses for video.  The smooth adjustment of the Leica DG Vario-Summilux 25-50mm F1.7 Asph’s aperture ring takes a little getting used to, but the display in the viewfinder or on the screen on the back of the camera makes it very clear what the aperture setting is.

It’s also good to see a push-pull mechanism to switch between automatic and manual focusing.  In manual focus mode, the focus distance scale is visible in both metres and feet, and the camera enlarges the image in the viewfinder as soon as the focus ring is rotated. It also displays a distance scale and the current focus distance.

While the manual focus ring can rotate indefinitely, there are discernible end points to the focus range.

Like the aperture and focusing rings, the zoom ring moves smoothly and easily but it takes a fraction more effort than the first two rings to move. It has markings to denote 25, 30, 35, 40, 45 and 50mm points and gives precise control over the image framing.

I received the Panasonic Leica DG Vario-Summilux 25-50mm F1.7 Asph less than 24hours before its announcement, which means I’ve only had time to shoot a few images with it on the GH5 II. However, my first impressions of it are very good. Firstly it has an excellent level of sharpness throughout the focal length range and across the image frame.

Even when the aperture is wide open at f/1.7, the images look super-sharp and there’s only very slight fall off towards the corners of the frame.

Vignetting is also controlled very well but as you might expect, it’s ‘least good’ at the 25mm end with the aperture at f/1.7. Closing the aperture to f/2 reduces to corer shading so its hardly noticeable, but if you swap quickly to an identical image captured at f/2.8, you’ll see the corners brighting fractionally.

Curvilinear distortion doesn’t appear to be an issue. If you switch the correction profiles on and off in Adobe Camera Raw while examining an image with lots of straight lines, you may spot a slight difference, but it’s minimal.

I need to shoot more images to be sure, but so far, I haven’t found any reason to think that chromatic aberrations are problematic with the Leica DG Vario-Summilux 25-50mm F1.7 Asph.

One thing that is very clear after using the Leica DG Vario-Summilux 25-50mm F1.7 Asph on the GH5 II is that its focus mechanism is silent. Focus breathing also appears to controlled very well, but I want to look at that in more detail over the coming days.

With a maximum aperture of f/1.7, it’s possible to blur background dramatically and to isolate a subject. Out of focus areas are attractively rendered and small highlights are round, without obvious aberrations.

Follow the link to browse and download full-resolution images shot on the Panasonic GH5 II with the Leica DG Vario-Summilux 25-50mm F1.7 Asph.

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The early indications are that the Panasonic Leica DG Vario-Summilux 25-50mm F1.7 Asph is a high quality lens that is capable of delivering very attractive images. It’s impressive how much detail is visible and how well the sharpness is maintained across the frame.

Chromatic aberrations and curvilinear distortion both also seem to be controlled well and the bokeh is attractive.

My only concern at this stage is the lens makes a bulky partnership with a camera like the GH5 II or or G9, but they are well-matched.