Panasonic Leica DG Vario-Summilux 10-25mm F1.7 ASPH Review
Introduction
The Panasonic Leica DG Vario-Summilux 10-25mm F1.7 ASPH is a new fast standard zoom lens for the Micro Four Thirds camera system. It is the world’s first standard zoom lens to offer a maximum aperture of f/1.7 throughout its range.
Featuring silent, high-speed focusing thanks to a 240fps high-speed inner focus drive system, the dust/splash/freeze-resistant Panasonic 10-25mm lens offers a versatile focal range of 20-50mm in 35mm terms.
Optically it's comprised of 17 elements in 12 groups, including three aspherical lenses and four ED (Extra-low Dispersion) lenses, and has 9 diaphragm blades which help give the aperture a rounded shape.
The Leica DG 10-25mm has a de-clicked aperture ring for easier video recording, and there's also a traditional focus clutch mechanism which enables instant AF/MF switching and accurate manual focusing.
The Panasonic Leica DG Vario-Summilux 10-25mm F1.7 ASPH lens is priced at £1,799.99 / $1,999.99 in the UK and the US, respectively.
Ease of Use
Given the fast maximum aperture of f/1.7 on offer throughout the zoom range, the Panasonic Leica DG Vario-Summilux 10-25mm F1.7 ASPH is unsurprisingly large and heavy for a Micro Four Thirds lens, measuring 12.8cm in length and weighing 690g.
Zooming is not internal, so the lens barrel extends when zooming out from 10mm to the 25mm focal length, where it reaches its maximum length (it's actually shortest at 13mm).
The lens has a focus clutch mechanism rather than an AF/M switch for choosing the focusing mode. When the focusing ring is pushed forward, the lens is locked into autofocus mode. When the focusing ring is pulled back, the focusing distance scale with depth-of-field markings is revealed and you can manually focus with the lens - very neat.
Note that this is a focus-by-wire lens which uses a stepping motor. There are hard stops at both ends of the 0.28m/0.92ft to infinity focusing range, but no depth of field scale on the barrel.
The Panasonic Leica DG Vario-Summilux 10-25mm F1.7 ASPH lens offers silent focusing, making it perfect for video recording. In use, we found the AF system to be very quick, accurate and reliable on the flagship Panasonic G9 camera.
The Panasonic Leica DG Vario-Summilux 10-25mm F1.7 ASPH has a traditional aperture ring on the lens barrel, which allows you to set the aperture in 1/3 steps, complete with aperture markings on the lens barrel. The aperture is also shown in the viewfinder or on the LCD screen as you change it.
The rather thin aperture ring toggles between auto aperture control (the ring is set to A) or manual aperture control (the ring is set to one of the aperture values).
The aperture ring proved to be nicely damped in use, although because the ring is declicked, the lens is better suited for video use than for stills, as it's difficult to set the aperture accurately to one of the 1/3rd values without having to double-check it via the viewfinder or rear LCD screen.
The 77mm filter thread does not rotate on focus, which is good news for users of polarisers and graduated neutral density filters.
The Panasonic Leica DG Vario-Summilux 10-25mm F1.7 ASPH has a lens mount is, thankfully, made of metal. The lens also boasts a dust and splash-proof design and is even freeze-proof down to -10℃, although Panasonic stops short of calling it fully weatherproof.
Usefully the lens comes with a good quality petal-shaped hood with a button to lock it into place and release it. Panasonic also include a cloth storage bag in the box.
Focal Range
At the 10mm end of the zoom range, the lens has a diagonal angle of view of 94°, equivalent to that of a 20mm lens in a 35mm system.
Field of view at 10mm
At the 25mm end, the angle of view is 47°, which is the same as that of a 50mm lens on a 35mm full-frame camera.
Field of view at 25mm
Chromatic Aberrations
Chromatic aberrations, typically seen as purple or blue fringes along contrasty edges, are not a problem with the Panasonic Leica DG Vario-Summilux 10-25mm F1.7 ASPH lens.
Light Fall-off and Distortion
With the Panasonic Leica DG Vario-Summilux 10-25mm F1.7 ASPH lens set to its maximum aperture of f/1.7, you can see some light fall-off in the corners, but nothing too excessive. There is some fairly obvious barrel distortion too at 10mm, but again it's not too extreme.
Vignetting at 10mm
Vignetting at 25mm
Macro
The Panasonic Leica DG Vario-Summilux 10-25mm F1.7 ASPH lens has a maximum 0.14x magnification rating and is able to focus at 0.28m / 0.92ft away from the subject.
Bokeh
Bokeh is a word used for the out-of-focus areas of a photograph, and is usually described in qualitative terms, such as smooth / creamy / harsh etc. In the Leica DG Vario-Summilux 10-25mm F1.7 ASPH lens, Panasonic employed a diaphragm with 9 rounded blades, which has resulted in very nice bokeh, at least in our opinion. However, recognising that bokeh evaluation is subjective, we have provided a few examples for your perusal.
Sharpness
In order to show you how sharp this lens is, we are providing 100% crops on the following pages.