The Panasonic lenses now come in four distinct looks: There are the basic lenses, with the matte appearance and grey ring close to the camera. Then, we have the Leica-branded lenses, which are matte black, without the grey ring.
The two Lumix X branded powerzoom lenses, Lumix X PZ 14-42mm and Lumix X PZ 45-175mm, which have a glossy black finish.
Finally, in 2012, we got the two f/2.8 zoom lenses, with the premium metal finish. The lens barrel is made of anodized metal with a purple-ish colour. This leaves me a bit unhappy. The lens barrel has two functions, in my opinion: To be solid, and to provide a good grip. With the latter in mind, why make it out of glossy metal? Other manufacturers go for a matte crinkle finish, which I think is better.
While the two kit zoom lenses above look similar, they are in fact very different. The Lumix G 14-42mm basic kit lens has a plastic lens mount, and is a very light lens. The Lumix X 12-35mm lens has an OIS switch on the barrel, and is much more heavy.
The zoom ring on the Lumix G 14-42mm basic kit lens is plastic, and feels a bit sticky when I rotate it. The Lumix X 12-35mm lens, on the other hand, has a rubberised zoom ring, which is very smooth to rotate, and well dampened. Even without a power zoom function, it is possible to zoom very smoothly during video using this lens, due to the well dampened zoom ring.
The lens comes with a hood in the box. The hood is well designed, and I certainly recommend using it. The only downside is that the ends are very rounded, meaning that you cannot safely put it upside down on a table.
The focus ring is not rubberised, which is perhaps a bit of a disappointment. But using the focus ring still works quite well. Just like the zoom ring, it has a very smooth and nice damping, even if it doesn't directly control the focus. Just like the majority of the Micro Four Thirds lenses, the manual focus is "by wire".
I've tested the two kit zoom lenses on the Panasonic GH3 in the same conditions:
With both lenses at 35mm, the camera spent 0.225s focusing with the Lumix X 12-35mm lens, and 0.298s with the Lumix G 14-42mm lens. Here is another test, showing that the focus speed is even quicker at 12mm, which is quite common for the kit zoom lenses.
In general, this lens focuses very quickly and virtually inaudibly. This is what one would expect from a premium lens like this.
I made a sharpness comparison at close focus distance, comparing the lens with the Lumix G 14mm f/2.5 pancake, and the Sigma 30mm f/2.8 EX DN. The tests were not entirely perfectly made, but they still show that the Lumix X 12-35mm has very good results in terms of sharpness. It is more prone to flare with strong light sources in the frame, though.
Here is another sharpness comparison with the Lumix G 14-42mm lens at infinity focus distance:
Here are the full images:
|Lumix G 14-42mm @ 14mm f/3.5||Lumix X 12-35mm @ 14mm f/2.8|
To evaluate the image quality, here are 100% crops from the top left corner:
Here, we see that the Lumix X 12-35mm lens is the sharpest, even at f/2.8, wide open. The corner sharpness is very good.
Here are the full images, taken at wide open:
|Lumix G 14-42mm @ 35mm f/5.2||Lumix X 12-35mm @ 35mm f/2.8|
From the top left corner, I took these 100% crops:
Here we see that the Lumix X 12-35mm lens is a tad bit soft at f/2.8, but becomes very sharp at f/4.
You can find some out of focus rendering (bokeh) for the Lumix X 12-35mm lens here.
Here are some example images taken at close focus distance, so you can see how the out of focus rendering is. Click on the images to enlarge them:
|Lumix G 14mm f/2.5 @ f/2.8||Lumix X 12-35mm @ 14mm f/2.8|
Here are some 100% crops from the centre using both lenses:
We see that the Lumix G 14mm f/2.5 has somewhat non-circular bokeh outside of the centre of the image frame. The Lumix X 12-35mm lens gives you more smooth out of focus rendering here.
And at 30mm:
|Sigma 30mm f/2.8 EX DN @ f/2.8||Lumix X 12-35mm @ 30mm f/2.8|
And centre crops from both lenses:
In this comparison, we again see that the Lumix X 12-35mm lens renders the out of focus background the nicest. The Sigma 30mm EX DN lens renders the out of focus highlights with somewhat hard edges and ringing, making the background look more busy. The Lumix X 12-35mm lens gives much more smooth background.
Geometric distortion correction
Like most Micro Four Thirds lenses, this lens also uses in-camera software corrections to give rectilinear images. In the wide end, the lens natively has some heavy barrel distortion, which is corrected. In the long end, there is no geometric distortion correction at all. Read more about it here.
Even after the software distortion correction, there is some residual barrel distortion in the wide end, and some pincushion distortion in the long end, especially at short focus distance. This is a bit disappointing.
Here is an example image illustrating the barrel distortion at 12mm:
I put an orange ruler into the image, to make it easier to see barrel distortion. This was taken at infinity focus. At closer focus, there is even more barrel distortion.
Here's an example at 35mm as well, showing the pincushion distortion:
This image was taken at 26mm, f/4, ISO 200, 1/60s with the GH3:
This image was taken at 12mm, f/3.5, ISO 200, 1/200s with the GH3:
And some 100% crops from the image:
This video was recorded with the Panasonic GH3 camera, at f/2.8, in a dimly lit location, handheld:
This is a very good performing lens, with few flaws. It is probably the best lens I have ever used. However, it comes at a rather steep price.
If you want to pay the price, you get a very good lens.