Panasonic Leica 25-50mm F1.7 ASPH field review

Introduction

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Overall score

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Panasonic’s Leica DG Vario-Summilux 25-50mm F1.7 ASPH is a bright zoom lens aimed at photographers using Micro Four Thirds camera bodies.

With a 35mm-equivalent focal range of 50 to 100mm, the 25-50mm F1.7 could make for an attractive – if somewhat unusual – portrait lens for still photographers. But it’s clearly been designed first and foremost for video capture, where it makes a really great companion for Panasonic’s existing 10-25mm F1.7 lens.

Available from August 2021, list pricing is set at $1799.99.

All images edited in Adobe Camera Raw 13 with adjustments limited to white balance, exposure, highlights, shadows, white and black levels. Sharpening and noise reduction at ACR defaults. Images were captured using lenses that were physically pre-production, but final optically.

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Handling | Autofocus and focus breathing | Image quality | Conclusion | Samples

Key specifications:

• Focal length: 25-50mm (35mm-equivalent: 50-100mm)
• Aperture range: F1.7 – F16
• Stabilization: No
• Filter thread: 77mm
• Close focus: 0.28m (11.0″)
• Maximum magnification: 0.21x (35mm-equivalent 0.42x)
• Diaphragm blades: 9
• Hood: Included
• Weight: 654g (1.44 lb)
• Optical construction: 16 elements in 11 groups (1 aspherical, 3 ED, 1 UHR)

With 35mm-equivalent focal lengths ranging from 50 to 100mm, the Leica 25-50mm F1.7 stands out from more common focal lengths like the wider 24-70mm or more telephoto 70-200mm zooms offered by many manufacturers. It’s probably not too surprising, then, that there aren’t really any direct competitors.

The closest we could find for the Micro Four Thirds mount is the Olympus M.Zuiko Digital ED 12-40mm F2.8 Pro, which is effectively a 24-80mm, but that’s still a good deal wider than Panasonic’s lens. And while it carries Olympus’ Pro designation, it’s still only a little more than half the price of the rather more niche 25-50mm F1.7, despite offering similar levels of weather-sealing and the same autofocus drive type.

ISO 400 | 1/1600 sec | F1.7 | 100mm equiv. | Panasonic GH5 Photo by Jordan Drake

Olympus’ lens is also far more compact and lightweight as you’d expect given its significantly less-bright maximum aperture, and it can focus even closer to deliver a better maximum magnification. The Panasonic / Leica lens has a nine-bladed aperture, versus the seven-bladed iris of the Olympus, though.

With no really close competitors, it probably makes more sense to focus instead on which lens the 25-50mm F1.7 will pair best with, and here there’s a very clear pick. With near-identical handling, not to mention similar price tags and the same videocentric design goals, this optic is clearly intended to be used alongside the Panasonic Leica DG Vario-Summilux 10-25mm F1.7 ASPH lens.

ISO 200 | 1/5000 sec | F2.8 | 50mm equiv. | Panasonic GH5 II Photo by Dan Bracaglia

The most obvious sign of Panasonic’s intent can be inferred from the fact that both lenses, despite their differing focal lengths, share essentially the same body design, right down to the size and placement of their control rings. That not only provides for muscle-memory familiarity when switching between the pair, but for videographers specifically, also makes them better-suited to use with the same follow-focus system setup as you swap back and forth between lenses.

Both lenses are also very closely-related in terms of their weight and balance, which should ensure that gimbals can accept either lens without need for adjustments to compensate for the optic in use. And at their shared 25mm focal length, both lenses also provide near-identical color and contrast, making it easier to match your shots.

ISO 320 | 1/80 sec | F5.6 | 74mm equiv. | Panasonic GH5 II Photo by Richard Butler

And of course, since they share the same overall body design, both lenses also accept the same 77mm filter sizes. They’re also both weather-sealed and share nine-bladed apertures. The biggest difference is in the use of a linear motor-driving AF system for the 25-50mm rather than a stepper motor-based system in the 10-25mm, giving greater AF performance to the more telephoto lens of the pair, where it’s more likely to be needed.

Compared to…

Handling

The Leica 25-50mm F1.7 is a fairly chunky lens, with a barrel diameter of 87.6mm (3.5″) and a length of 127.6mm (5.0″), but that’s to be expected given its bright maximum aperture. And its construction certainly befits its price tag, with a solid all-metal design including metal control rings.

But despite its size, solid build and the sheer number of glass elements within, it’s fairly lightweight for a lens of its type, tipping the scales at around 654g (23.1oz). And we found it to balance nicely on cameras with a decently-sized handgrip like the Panasonic GH5 and GH5 II with which we shot our sample galleries.

These three rings provide for control of zoom, manual focus and aperture. The manual focus ring includes a clutch mechanism, allowing you to quickly shift focus modes simply by sliding the ring back and forth.In all, there are three nicely-knurled rings encircling the body of the lens, and these serve as the only physical controls. All three turn very smoothly and offer just enough resistance to allow for easy operation either with a fingertip alone, or with motorized accessories and the like.

The aperture ring, meanwhile, has a near-stepless design that’s ideally suited for cinematography, allowing for smooth and gradual aperture changes during video capture. It’s not quite entirely stepless, as this is still a fly-by-wire system, but Panasonic’s micro-step aperture drive has sufficient accuracy to make the individual steps all but invisible.When it’s pulled backwards a scale indicating the focal distance is exposed. The behavior of the ring simultaneously changes from its default speed-sensitive control to instead provide linear control, allowing for precise, predictable and repeatable focus adjustments.

Unfortunately, there’s no way to enable click detents for the aperture ring, but there is a simple solution if you need more precise aperture control. You can simply place the ring in its Auto position, as denoted by a red letter A, and then use the controls on your camera body to set the aperture value instead.The aperture drive is also silent, and with no clicks from the aperture ring itself, you needn’t fear aperture changes being picked up on your audio track either. And the ring has sufficient throw to minimize the risk of significantly changing the aperture value by mistake.

No optical image stabilization is provided, although you can of course rely on the in-body image stabilization of your camera, if available. It’s still a bit of a shame, though, as it means you’ll miss out on the even better corrective power offered by the Dual I.S. systems that utilize in-body stabilizers in tandem with lens stabilizers that’s available on some bodies.The lens is also comprehensively weather-sealed, not just with a gasket at the interface between the lens and body, but also at the individual controls and seams between the lens’ component parts. Panasonic describes the 25-50mm F1.7 as both splash and dustproof, and says it is also freezeproof to -10ºC (14ºF).

Up front, you’ll find 77mm threads with which to attach your choice of filters, and a locking hood (shown above) is included with the lens.

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Autofocus and focus breathing

Although manual focus was clearly a priority for the Leica 25-50mm F1.7, Panasonic hasn’t neglected autofocus in the least. A linear autofocus motor provides for both very swift and silent autofocus, making the most of the company’s fastest AF systems which can sample focus distance information a whopping 240 times per second (when shooting stills).

The result is a lens that can rack from its minimum to maximum focus distance in under half a second – so that you can be confident of keeping up with the action for typical subjects like street photography, even bearing in mind the lens’ shallow depth of field.

ISO 200 | 1/800 sec | F2 | 80mm equiv. | Panasonic GH5 II Photo by Dan Bracaglia

Manual focus operation, too, is smooth, silent and accurate. As with most mirrorless lenses, it doesn’t operate mechanically, but even though it’s a fly-by-wire system it operates exactly as if it were mechanically coupled when the focusing ring is in the manual position, providing good repeatability.

And if you prefer swifter shifts in manual focus distance, switching the focus clutch back out of manual mode and selecting manual focus on the camera will give you speed-sensitive control instead.

ISO 200 | 1/60 sec | F1.7 | 100mm equiv. | Panasonic GH5 Photo by Jordan Drake

This isn’t by any means a macro lens, but the 25-50mm F1.7 offers good close-up capability. The minimum focusing distance varies only slightly from 28cm (11″) at the wide end of the range to 31cm (12.2″) at telephoto. The latter translates to a maximum magnification of around 0.21x, which equates to 0.42x magnification on a full-frame camera.

We’ve already discussed the 25-50mm’s physical design, stepless aperture control and focus clutch, all of which are boons for videographers, but the good news doesn’t end there. It is also extremely well controlled when it comes to focus breathing, meaning that you can refocus without noticeably changing your framing, regardless of whether you’re shooting at the wide or telephoto ends of the zoom range.

ISO 200 | 1/3200 sec | F1.7 | 100mm equiv. | Panasonic GH5 Photo by Chris Niccolls

Really, the only downsides for video use are the lack of in-lens stabilization and the fact that this isn’t a parfocal lens. What that means is that if you adjust the focal length, it will also change the focal distance. As a result, zooming in or out will necessitate an adjustment to focus.

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Image quality

At this price point and given its size, you’d expect image quality to be good to great, and Panasonic’s Leica 25-50mm delivers. The bokeh isn’t perfect when specular highlights are present, but is nevertheless nice overall, and detail-gathering is very good even when shooting wide-open.

ISO 200 | 1/1250 sec | F3.2 | 60mm equiv. | Panasonic GH5 Photo by Chris Niccolls

Sharpness

The 25-50mm F1.7 does a great job when it comes to central sharpness. Even when shooting wide-open, image centers are very, very sharp across the zoom range, and stopping down a little can deliver no improvement on that sharpness. We did see a little improvement in the corners when stopping down to F2.8, however, especially towards the longer end of the zoom range.

ISO 200 | 1/50 sec | F2.8 | 100mm equiv. | Panasonic GH5 Photo by Jordan Drake

Bokeh

This lens can also deliver nice results in the bokeh department, giving great opportunities for subject isolation when shooting wide-open, especially at closer focal distances. The only real downside is with specular highlights, which can be a bit busy due to noticeable onion ring effect. There’s also some noticeable cats-eye effect, seen in the image below, but it’s not too extreme and therefore not too distracting.

ISO 200 | 1/1000 sec | F1.7 | 100mm equiv. | Panasonic GH5 Photo by Chris Niccolls

Flare, ghosting and sunstars

Panasonic includes a quite deep, tube-style lens hood in the product bundle, which attaches to the front of the lens with a button-released catch that nicely prevents accidental disconnections.

The lens shows an impressive resistance to both flare and ghosting when shooting into bright light sources, though you can get some ghosting to appear if you try hard enough. But most of the time, as you can see below, ghosting just isn’t a problem. Sunstars are of the 18-pointed variety, courtesy of the nine aperture blades the lens uses, and they’re of good quality if not the best we’ve seen. The spikes can be a little uneven in length and tend to diffuse rather quickly.

ISO 200 | 1/400 sec | F16 | 50mm equiv. | Panasonic GH5 II Photo by Dan Bracaglia

Longitudinal / lateral chromatic aberration (fringing)

Although we did see a little bit of longitudinal chromatic aberration or LoCA, which causes color fringing in the foreground and background and can be hard to correct post-capture, it was pretty average and manageable, and not something we’d be concerned about.

As for lateral chromatic aberration or LaCA, we didn’t find this to be an issue.

Color fringing in areas in front of and behind the plane of focus is really well controlled. ISO 200 | 1/ 2500 sec | F1.7 | Panasonic GH5 Photo by Chris Niccolls

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Conclusion

With the Leica DG Vario-Summilux 25-50mm F1.7 ASPH, Panasonic has clearly focused on an unanswered gap in the Micro Four Thirds lens market. That’s no bad thing, but it does mean that this isn’t a lens for everyone, as its rather unusual focal range might suggest.

But if you find yourself in that niche – perhaps already owning the externally similar 10-25mm F1.7 and craving a bit more telephoto reach for video shooting or portrait stills – then this lens has a lot to offer.

ISO 200 | 1/1600 sec | F2.8 | 100mm equiv. | Panasonic GH5 II Photo by Dan Bracaglia

Panasonic’s attention to detail in designing these two lenses to work hand-in-hand is both impressive and thoughtful. Not only has it given both optics the exact same body and control layout, but it has also matched the look of both lenses well where their focal ranges meet. That will mean less work for videographers both in the field, and when it comes time to get down to editing.

We already loved the earlier 10-25mm F1.7, and this lens is an extension of everything we loved about the earlier one. Like that optic, it’s a joy to shoot with whether using autofocus or pulling focus manually, and it delivers great image quality in most respects as well.

ISO 200 | 1/400 sec | F2 | 76mm equiv. | Panasonic GH5 II Photo by Dan Bracaglia

Yes, it is quite pricey, but that’s to be expected in a niche product, and doubly so in a videocentric lens like this one. And even for photographers who’ll never shoot video, it is pretty much the only game in town if you want a really fast, native portrait zoom.

Can it justify that price tag? That will depend upon what you’re shooting, but for videographers in particular, we think you’ll be thrilled with it.

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Scoring

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DPReview TV review

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Sample galleries

Please do not reproduce any of these images without prior permission (see our copyright page).

Panasonic GH5 II (DPReview HQ gallery, pre-production but optically final lens)

Panasonic GH5 (DPReview TV gallery, pre-production but optically final lens)

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