Monday, 12 December 2011

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A newer version of the lens was launched in 2011, the Lumix G X PZ 45-175mm, with Power Zoom (PZ).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.

7 comments:

  1. G@45mm images are out of focus, it's a good review but it would be interesting to repeat the test with that focal in daylight with a more detailed subject than what you used for the second series. It would be interesting to shoot the same subject with a 45mm prime lens too (oly or pana)

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  3. Thanks for the test shots! Could you compair 45-175 X side by side with 14-140 lens? I guess in terms of sharpness 45-175 X is better performer, but would be nice to see outdoor shot!

    Btw, great blog, checking it every day;)

    Regards,
    Niko

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  4. Hi, I am looking to buy a lens in this range for my Lumix GF1 and would like a lens that is an F/2.8 , the Olympus Zuiko Professional ED 50-200 mm F/2.8-3.5 DIGITAL Lens Four Thirds looks like a great one. Can this lens work on one GF1 with a lens adaptor, if so what are the quality of the photos. Any information would be great! Thanks!

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  5. The Olympus 50-200mm f/2.8-3.5 lens is not a compatible lens. So you can mount it to your camera using an adapter, but it will not autofocus on your camera. You're stuck using manual focus.

    I'm sure it is a fine lens, though. I would recommend getting a Panasonic lens for your GF1 camera, since OIS is a good feature to have for a tele zoom lens. You can get the Lumix G 45-200mm lens (if you're on a budget), the Lumix G 45-175mm lens (if you value compactness), or the Lumix G 100-300mm lens (if you need a very long lens).

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  6. To my side, the test shots of 45-200mm seems always have clearer texture. Espically for those at 45mm, the 45-175mm seems produce bluring image. Is the best aperture of 45-175mm around F8?

    Great test and sorry for any offence.

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  7. @Xanadu
    "To my side, the test shots of 45-200mm seems always have clearer texture."

    At first glance, I had the same reaction: the 45-200mm pictures have "clearer texture". However, this is akin to digital sharpening of an image. That is, if you look carefully at the beer logo close-ups, you will notice that despite having "clearer texture", the 45-200mm lens actually takes away some details within the image and creates pixelated borders (similar to aliasing) -- take a look at the "oblique lines" below the "E" from Erdinger and the borders of the "W" from Weissbräu in the close-ups.

    I have not tried this since I do not own either of the lenses, but I expect that, after having slightly sharpened the 45-175 images with Photoshop, we would get a result similar to the 45-200 (i.e. clearer texture) while retaining more detail with regards to the actual scene.

    The sharpness of the 45-200 seems slightly overdone IMHO. The again, I love the extremely sharp 20mm panny lens... :)

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