Sharpness of Lumix G 45-200mm and Lumix X 45-175mm

Note: Since this test, I have done another one in a more challenging lightning.

The Lumix G 45-200mm tele zoom was one of the first Micro Four Thirds lenses launched. It is a value tele zoom, and as such, it does a good job. It does indeed provide good value for money. But it is often seen not too sharp, especially in the longer end of the zoom reach.

A newer version of the lens was launched in 2011, the Lumix G X PZ 45-175mm, with Power Zoom (PZ). It also sports a number of other innovations, for example non-extending zoom action, and nano surface coating. But does it improve on the original tele zoom lens in terms of sharpness?

Lumix G 45-200mm (left) and Lumix X PZ 45-175mm (right)

I have tried to answer this by photographing a simple test setup with the Panasonic GH2 camera on a tripod, using the Panasonic FL360 flash unit for illumination. The flash was angled up towards the white ceiling to spread the light better. The ISO was set to 160, and the shutter speed to 1/60s.

1st series of tests

Here are the two shots at 45mm, from each lens. These images were scaled down and resharpened:

Lumix G 45-200mm @ 45mm f/4	Lumix X 45-175mm @ 45mm f/4

The focus distance was about 1 meter. A distance of one meter at 45mm focal length corresponds to taking a headshot portrait picture. In both cases, I set the focus point on the centre beer bottle logo.

Let's look at enlargements for a better view (the older Lumix G 45-200mm in the top row, and the new Lumix X 45-175mm in the bottom row):

I also tested them in the same way at maximum magnification. In this case, the focus distance is about 2 meters. Here are downscaled versions of the whole images frames:

Lumix G 45-200mm @ 200mm f/5.6	Lumix X 45-175mm @ 175mm f/5.6

And here are 100% crops from the images taken at maximum zoom extension:

Using the flash for illumination has a great advantage: It freezes the image, and camera shake is no problem. On the other hand, the flash cannot quite illuminate the subject sufficiently at f/8, which makes those exposures a tad bit darker. If I had angled the flash towards the subject, rather than up into the ceiling, this would of course be no problem. But having the flash face the subject would create a reflection effect, which is not good for this comparison.

Conclusion

At 45mm, there is not a huge difference between the lenses. In this experiment, they are quite comparable, I would say. In the longest zoom reach, I would say the newer Lumix X 45-175mm lens has somewhat better clarity wide open at f/5.6.

Perhaps it is a bit unfair to compare the old lens at 200mm with the new lens at 175mm, but I believe this is how people would typically use them: When you need a long reach, you usually zoom to the very end.

2nd series of tests

Again, the focus distance is around 2 meters. This time, I use the ambient light, at ISO 160. The shutter speeds were around 1s. To avoid camera shake, I used 2s shutter delay. That way, any shake induced by pressing the shutter is allowed to calm down before the image is taken.

A centre focus point was used.

Lumix G 45-200mm @ 45mm f/4	Lumix X 45-175mm @ 45mm f/4

Here are 100% crops from the centre of the image:

And from the lower left corner:

Conclusion

The second test shows that both lenses are pretty much equally sharp in the centre at 45mm. It also confirms the conclusion from the first series of the test: The newer Lumix X lens is sharper in the corner part of the frame. It also appears to handle flare somewhat better. Perhaps the hyped "nano surface coat" is actually doing something for the image quality.