Panasonic Lumix G 42.5mm f/1.7 ASPH. POWER O.I.S. lens review
I feel it is fitting to start this brief review with the same paragraph I opened the review of the Leica Summilux 15mm f/1.7 lens with.
Properly done, lens testing is a weighty undertaking: you need to examine a number of performance factors at different distances and for a handful of lens copies to account for sample variations (and if you buy a zoom lens, good luck). I do not have access to multiple lens copies, and I am usually not interested in performance at close distances. Thus, the purpose of my tests is not to pronounce the ultimate verdict; instead, it is to determine whether my copy of a lens is an overall decent performer, how well it performs wide–open, what aperture setting delivers best image quality, as well as what aperture I choose for maximum depth of field. I further look at a lot of real–life images to see if any peculiarities draw my attention. Once I am satisfied that a lens is a keeper and know what I need to know, I move on.
Panasonic Lumix G 42.5mm f/1.7 ASPH. POWER O.I.S. lens (image courtesy of Panasonic)
The Panasonic Lumix 42.5mm f/1.7 is a short telephoto lens for the M43 format advocated by Panasonic and Olympus. Its field of view is approximately equivalent to 85mm in full–frame (35mm) format, which is a classic focal length for portraiture or compressed land– and city–scapes. Indeed, it is my favorite focal length in the short telephoto range—nearly always, it is a natural and perfect match to how my mind's eye sees whenever I photograph people or visualize an image with compressed perspective.
The Lumix is well built and feels quite solid in hand, although it is not as dense or sexy as, say, the all–metal Leica Summilux 15mm f/1.7 lens. It is truly small and light, too–indeed, it is perfectly pocketable (the other day I shoved it into my shorts' pocket when changing to another lens to grab a quick shot; a few hours later I had to remember where it was!). Autofocus is swift and resolute on the Panasonic GX8 camera. Focusing ring is fairly wide and right there for you when you need it (there is nothing else to grab on the barrel, really); it is smooth in operation to boot. What sets the Lumix apart from its nearest counterparts–namely, the Leica 42.5mm f/1.2 and the Olympus 45mm f/1.8–apart from the obvious aperture and focal length differences is much closer focusing distance: 31cm of the Lumix vs. 50cm of both the Leica and the Olympus. To me, this was a deciding factor: I am not a macro shooter, but I do like to get closer to certain subjects than the other two lenses allow. What also differentiates it from the Olympus is built–in optical stabilization, which the Lumix has and the Olympus lacks. The Leica, of course, is a notably faster lens, but it is massive and much more expensive in comparison—you need to be sure you absolutely must have that extra brightness.
Optical performance of the Lumix is sweet. By this I mean that while it does not break any performance records and it is not a lens you would choose to brag about, whatever flaws it has are of such degree and nature that they are quite below the objectionability threshold and may even contribute to the lens' rendering character.
Centre sharpness is already very good wide–open and improves slightly as you stop the lens down. As can be anticipated, corner sharpness is a bit worse than in the centre at f/1.7, but the difference is in the range of "perfectly expected and acceptable". It improves as aperture setting gets smaller and nearly catches up with the centre. Overall sharpness peaks around f/5.6, upon which diffraction starts gradually taking its toll. The lens produces very mild barrel distortion that is of a simple nature and easily corrected in software without any consequences. Chromatic aberration can be easily noticeable, but it is not a thorn in your eye. While not "dreamy" or "smooth as butter", bokeh is nice and not distracting (but much less so when it comes to foreground bokeh). Below is a good example of all of this: if you look closely you may notice a lot of imperfections, yet overall image quality is far from objectionable (and this is the worst case I could find). All things considered, the Lumix's performance is, well, sweet.
Panasonic Lumix 42.5mm f/1.7 lens: flaws fail to ad up to objectionability
One question that you may have on your mind is whether f/1.7 on a M43 camera gets you enough out–of–focus blur, and if you can get your subjects isolated enough from the background for portraiture. Here, I feel the need to quote William Blake first:
The road of excess leads to the place of wisdom. You never know what is enough until you know what is more than enough.
So how much out–of–focus blur is too much? From my perspective, it is when you have one eye in focus and the other slightly blurred, or both eyes in focus but the tip of the nose and ears blurred, or when you have more than one person in the frame and one of them is slightly out of focus. Having used fast aperture lenses on full–frame cameras and done my share of chasing the shallowest depth–of–field possible, I am now of the opinion that the main advantage of super–shallow depth–of–field is bragging rights: "Look what I can do!" When photographing people, I now want the head of the subject—and of all subjects—to be in focus, with mildly blurred background and non–distracting bokeh. And for that, f/1.7 on a M43 sensor fully suffices. If anything, I often find myself stopping down to f/4 to get enough depth–of–field. If I were to be given a large, f/1.4 or faster, full–frame lens today, I would say thanks, but no thanks.
So what I found in the Panasonic Lumix 42.5mm f/1.7 is a warmly familiar short telephoto focal length with sufficiently fast maximum aperture but in a much smaller and lighter shape than what I am used to seeing it in. It still makes me smile. Although not a single aspect of its performance screams "breakthrough", the whole package is a lot more than just the sum of its parts. It boasts unexpected charm. In fact, I like this lens to the point that it has made me committed to the M43 platform: I recently sold my GX8 camera* and this lens has convinced me to go for the GX9 just so that I can continue using it**!
*It is a nice camera, but I disliked the very features most photographers seem to adore. To me, the GX8 felt quite a bit bloated, particularly given the sensor size, which I did not appreciate during travels. I did not like its articulated screen—swinging it all the way out was a nuisance. The sensor was quite good, but images lacked that extra bite because of anti–aliasing filter and required extra fiddling with sharpening in post–processing. So I passed the camera on to the next user while it was still fresh enough to command a decent selling price.
**Which is no mean feat in my book: when was the last time you stayed with a camera line so that you can continue using one particular lens? For one thing, the Leica Summilux 15mm f/1.7 lens, which many consider a desirable optic, could not get even close to achieving as much for me.