Saturday, 31 December 2011

Lumix X HD PZ 45-175mm f/4-5.6

The new, compact tele zoom Panasonic Lumix X HD PZ 45-175mm f/4-5.6 has a long name, indicating a lot of improvements over the existing value tele zoom Lumix G 45-200mm f/4-5.6. In this review, I have mostly been comparing the lenses head to head. I think this makes sense, since most users will be choosing between them, and hence would like to know how they compare, and if the newer lens is worth the premium price.


Lumix G 45-200mm f/4-5.6 (left), Lumix X PZ 45-175mm f/4-5.6 (right)

Specifications

Lens
Lumix G 45-200mm
Lumix X 45-175mm
Weight380g210g
Length100mm90mm
Diameter70mm62mm
Filter thread52mm46mm
Minimum focus1.0m0.90m
Maximum magnification0.19x0.2x
Lens elements1614
Lens groups1310
Exotic elements3 ED2 Asph, 2 ED
Diaphragm blades77



Based on the specifications, it is easy to see that the newer lens looks more interesting. It is smaller, lighter, has more exotic lens elements. The only negative item is that it has a shorter zoom range. However, the difference between 200mm and 175mm maximum extension is barely significant.



Aperture range

In the specifications, it looks like the two lenses have the same aperture range. And they do have, f/4-f5.6. However, when looking at the aperture as a function of the focal length, it is easy to see that the new lens in fact has a less impressive maximum aperture for all focal lengths between the start and end-points:


This means that the new lens not only gives a slightly shorter zoom range, it is also a slower lens on average. However, I guess that lenses like this tend to be used in the very shortest and very longest settings the most, so this might not be big issue.

Physical, Power Zoom

The most striking difference between the lenses is of course the size and weight. Beyond that, the newer 45-175mm lens has the all-black "premium design", associated with the Leica branded lenses from Panasonic. The older 45-200mm lens has the "common design", featuring a grey ring around the base of the lens.

Another fundamental difference between the lenses is that the new lens has power zoom (PZ), and also internal zooming. Internal zooming means that the lens doesn't change shape during focal length change. The old lens, on the other hand, extends when zooming towards the long focal length range, which is very common for tele zoom lenses. Internal zooming makes the new lens feel very solid. There is no wobbling front section, unlike the older 45-200mm lens.

Power zoom is a feature mostly included for video use. Zooming smoothly manually during video recording is pretty much impossible. But with motorized zooming, it is possible to zoom while recording a video. On a personal note, I think that zooming during a video capture almost never looks good, and is best avoided. But at least the new lens makes it possible to do this with a better result.

For still image use, power zoom is not needed. And some would even argue it is a nuisance: You have better and more precise control with a manually operated zoom ring. However, I find the implementation of the motorized zooming to be very good. There is the option of zooming using a broad, rubberized ring, or using the switch on the side. Using the ring for zooming feels almost like using a mechanically coupled manual zoom ring. There are two exceptions: The zoom ring does not stop when reaching the end of the focal length range, and you cannot see the focal length by looking at the position of the ring. Rather, you must take a look at the display to see the actual focal length.

When using the zoom ring while recording a video, it has the advantage of smoothing out the zoom movement for you, so that the zoom action becomes more even. Using the zoom lever makes the zooming even more smooth. It is possible to operate the motorized zoom at different speeds using the zoom lever, by pushing it more or less hard. This works well

The rubber zoom ring feels a bit thicker and more generous than the old lens. Also, the focus ring feels a bit more dampened than the old lens.

Autofocus

I have tested the autofocus, and compared it with the older 45-200mm lens. I found the autofocus to operate a bit faster than the old lens. The old lens is also very fast focusing, so this is a good achievement.

As with other Contrast Detection Autofocus (CDAF) systems, the focus accuracy is very good. Unlike Phase Detection Autofocus (PDAF), calibration of the lenses and camera bodies is not needed. However, as with all other long lenses, you must take care that the camera focuses on what you want to have in focus. Even if the aperture is not very large in the long setting, f/5.6, the depth of focus (DoF) is still narrow enough that you may experience to focus on a background object rather than the subject. So make sure you understand how the autofocus modes work, and consider using centre spot mode to have full control over what comes in focus. This is important when using the lens in the longest tele zoom extension.

Autofocus while zooming

The older Lumix G 45-200mm f/4-5.6 lens is not optimal when it comes to keeping the focus when zooming. It is clearly not parfocal, and loses the focus immediately when zooming. The longer Lumix G 100-300mm f/4-5.6 is somewhat better in this respect, but still has this problem.

With the newer Lumix X 45-175mm lens, this is still a problem. When zooming during video recording, I've found that it can keep the focus fairly well if the background is static. However, with excessive subject movement or camera shake, the focus can wander off for an extended period of time. In general, you can not expect tack sharp focus until around one second after you stop zooming. This will take longer if the lens is zoomed in.

Here is an example showing how zooming while video recording can look using the two lenses:



As you can see, both lenses fail to focus perfectly while zooming. However, the newer lens generally does a bit better. Also, it is easier to zoom smoothly using the new lens. Especially when using the zoom lever. An added benefit is that keeping the camera stably is easier when using the motorized zoom through the lever.

I could find examples where the new Lumix X 45-175mm lens also fails to retain focus while zooming. This would typically happen if there is excessive camera shake, much subject movement, or very close distance. Closer distance is more challenging for the lens, especially at a long zoom.

Sharpness

When comparing the sharpness of the two lenses, it is hard to find much difference with low contrast test images. This can be seen here, in my first sharpness tests. However, with high contrast images, for example with back light, I've found the new lens to be consistently better. It has less Chromatic Aberration (CA) artefacts, and less flare.

I would say that the newer Lumix X 45-175mm lens is generally sharper wide open. When using a Panasonic camera in auto mode, it will almost always choose to use a long lens like this wide open, so the wide open performance is important.

Here is another sharpness comparison with four other lenses at 140mm. Again, the Lumix X 45-175mm lens comes out as one of the best performers.

Bokeh

The term bokeh denotes the rendering of out of focus areas, which can vary a lot between lenses. I have looked at the bokeh of the two lenses by using a high contrast night image as an example. The focus is set on the foreground, which is about 1m away. The focal length was 45mm in both cases. Here are the full images:
Lumix G 45-200mm
Lumix X 45-175mm

Looking at some 100% crops from the top right region reveals that the bokeh from the newer Lumix X 45-175mm is not optimal. The out of focus hightlights are rendered as non-round discs off the centre:


The problem of non-round out of focus renderings becomes smaller as the lens is stopped down. In low contrast situations, this is not an issue at all, since you wouldn't see the bokeh discs as clearly as here.

Optical Image Stabilization (OIS)

Just like almost all other zoom lenses from Panasonic, this lens features optical image stabilization (OIS). Based on my experience, this appears to be effective both during still image photography and video recording. It is almost impossible to video record stably at 45mm and longer focal length without a tripod, so OIS is pretty much needed for video.

In online forums, there has been much discussion about the effectiveness of the OIS with this lens. I cannot see how I can test this scientifically, and hence my advice is: If you are worried about the rumored dysfunction of the OIS, then don't buy the lens. My personal opinion is that this problem, if it is a problem, is way overrated in online forums.

Example images

Here is an example image taken at 45mm, f/4.0, ISO 160, 1/60s, OIS on, handheld:

And a crop from the centre of the image, not re-scaled or sharpened:


This image was taken at 175mm, f/5.6, ISO 320, 1/50s, OIS on, handheld, but with the camera supported against a railing:


And a crop from the middle of the image, not re-scaled or sharpened:



And this image was taken at 175mm, f/5.6, ISO 640, 1/125s, OIS on, handheld, but supporting my wrist on a hand rail:


And a crop from the top left part of the image, not re-scaled or sharpened:


Example video

This video was done with the GH3, using the Extended Tele Conversion (ETC) mode, and the zoom mostly around 100-175mm. The camera was handheld:



A video recorded using the GH2 at ISO 160, f/6.3 and mostly f=175mm. One of the wider shots was recorded at a shorter focal length.



The camera was hand held, but rested against a hand rail.

Another example video, recorded handheld with the GH2. The zoom was set to about 60mm.



I think the OIS system does a good job of keeping the image stable. Compare it with a video recorded using the Olympus M.Zuiko 45mm f/1.8 non-stabilized portrait lens. In the video recorded using the MZD45, I was not able to handhold the camera sufficiently stable.

Durability

After 1.5 years of extensive use, I accidentally dropped the lens on a hard wood floor from a height of 1.5 meters. The lens bounced a couple of times before coming to rest, and I thought that this lens is gone for sure. However, the only visible side effect from the accident is that some chrome has chipped off one of the mount flanges:



Beyond that, the lens works just as before, and continues to give very sharp and good images. This indicates that the lens is very well constructed, and can take a lot of abuse, should you be unlucky and drop it or bang it into something.

Conclusion

The newer Lumix X 45-175mm lens is a good improvement over the existing Lumix G 45-200mm lens. It is better optically, and much more compact and light. It also feels more solid, without any extending section when zooming. The power zoom (PZ) implementation is well done, and works fine also for still image use.

While some of the specifications are better than the old lens, it should be noted that some are also worse. The new lens has a slightly shorter zoom range, and is about 1/3 stop slower in the middle of the zoom range. Out of focus renderings of highlights are non-round outside of the centre of the frame. This is mostly a problem only for night time photos. The bokeh is quite good in daylight situations, when the contrast is lower.

So which lens should you buy? If you are interested in video use, then I think it makes sense to get the newer Lumix X 45-175mm lens, since it generally gives you better footage, and allows for smooth zooming while filming. The new lens could also give better image quality for stills use. All in all, I think it comes down to how much you want to spend, and how much you value the compactness. Both lenses are certainly good.




Thursday, 29 December 2011

AF speed comparison, Lumix G 45-200mm vs Lumix X 45-175mm

The Lumix X PZ 45-175mm f/4-5.6 has the "HD" designation, and it does have the newer "X"branding, indicating that it is a premium lens. I have already seen that it performs better in terms of optical qualities than the older Lumix G 45-200mm f/4-5.6 lens. But what about the focus speed?

I tried to put a figure at about 1 meter distance, close to the minimum focus distance of both lenses. Then I timed the focus. The camera had just been turned on, meaning that the lens is at "close to infinity" focus at the start of the experiment. There is a fair amount of light, with daylight coming in through a window.

Here are the results:



And in a table:

Focal length
Lumix G 45-200mm
Lumix X 45-175mm
45mm0.24s0.18s
max0.54s0.42s

Conclusion

In my tests, the newer Lumix X PZ 45-175mm does focus faster than the older Lumix G 45-200mm lens. The older lens was very fast focusing already, so this is a good achievement.

Tuesday, 20 December 2011

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

I have previously tested the sharpness of the Lumix G 45-200mm and Lumix X PZ 45-175mm lenses. My test images then were fairly low contrast, and not too challenging for the lenses. To put them to a more difficult test, I've tried to test them head to head with a backlit subject. This is taken at approximately infinity focus, which is perhaps not the most realistic usage of these lenses.


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

@ 45mm

The first set of images are taken at 45mm with both lenses. I used the Panasonic GH2 at ISO 160, and a tripod. The shutter speeds were fast. This is what the whole frame looks like:



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

Here are 100% crops from the centre:


And from the left corner:


I've also made a similar comparison at maximum zoom extension. First, the full images:

@ 175mm and 200mm



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

Here are 100% crops from the centre:


And from the left corner:


Conclusion

While my first test indicated that the lenses were fairly similar in terms of sharpness, these tests, taken at more challenging lightning, show a consistently better performance from the newer Lumix X PX 45-175mm f/4-5.6. The newer lens shows less Chromatic Aberration (CA) artifacts, and a better sharpness in the corner, especially in the longest zoom reach.

Wednesday, 14 December 2011

Lumix Leica 25mm f/1.4 and clicking sounds

The Lumix Leica DG Summilux 25mm f/1.4 is a premium large aperture prime lens for the Micro Four Thirds system. It is designed to work as a "classic" bright normal lens for a 35mm SLR system, which was typically rated as 50mm f/1.4. With the 2x crop factor associated with the 4/3 format, the Leica 25mm f/1.4 lens becomes equivalent to a classic normal lens in terms of field of view.


Many users have complained about clicking sounds when using this lens. This has left them worried: When they buy a premium lens, they expect it to function smoothly.

First of all: Don't worry, the clicking sounds are completely normal.

Having said this, let's look at why you experience these clicking sounds.

What's causing the clicking sounds is the change of aperture. In normal operation, the camera leaves the aperture at its largest value when using the camera, and only stops it down just before taking a picture. The aperture is opened up again afterwards. Since the sound of the shutter is louder than the actual aperture change, you don't normally notice the sound of the aperture changing.

I have examined the loudness of the aperture change with a number of lenses here. Generally, most lenses have a similarly loud aperture change. The Lumix G HD 14-140mm superzoom is marketed as a video lens, and is supposed to have more silent aperture change than usual.

However, the Lumix Leica 25mm f/1.4 is the brightest Micro Four Thirds lens so far. When using the camera, it is seeing the outside world through the lens, and relaying the information to you through the LCD screen, or the viewfinder. Unlike your eye, which is very flexible in terms of the dynamic range it can see, the camera sensor can only see a more limited range of brightnesses. When using a bright lens like the Leica 25mm, in combination with a bright surrounding, the light is simply too much for the sensor to process. It needs to stop down the aperture to show you a sufficiently good viewfinder image. Stopping down the lens causes a clicking sound.

Further, the camera cannot accurately focus with the lens stopped down. When stopped down, the depth of focus (Dof) is wider, hence the lens appears to be in focus in a large focus distance range. And this can cause misfocus.

So before focusing, the camera must open up the aperture fully, and then close down again afterwards, if the surroundings are very bright. Both opening up the aperture and closing down cause the clicking sounds. Hence, every time you focus the lens in a bright light, you will experience the click before and after the camera has achieved focus.

If you operate the lens in a dim environment, you should not normally experience the clicking sounds upon focusing the lens.

This can happen with any Micro Four Thirds lens, even relatively slow zoom lenses, given that you point the lens towards a strong light source. But since the Leica 25mm f/1.4 is unusually bright, it happens more often with this lens.

So to conclude: The clicking sounds are a normal part of the lens operation.

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.