Better focus with Lumix G 100-300mm Mk II

The original Lumix G 100-300mm f/4-5.6 was an affordable and basic long tele zoom lens, from the early days of Micro Four Thirds. It was generally considered a good value lens, albeit not optimally sharp in the long end, and with newer cameras, the continuous drive mode became slower in AF-C, due to a slow aperture mechanism.

Unexpectedly, since there is already the high end long tele zoom lens Leica 100-400mm, the 100-300mm lens has been upgraded to a Lumix G 100-300mm Mk II. The optical design, and, indeed, the lens body, is exactly the same, however, it gets a newer focus motor, aperture mechanism, and compatibility with newer IBIS (In Body Image Stabilization).

The lens is longer than most consumer tele zoom lenses, reaching a whopping 600mm (35mm equivalent) in the long end. For example, the Nikon Z 50-250mm f/4.5-6.3 reaches 375mm in 35mm equivalents.

Lumix G 100-300mm Mk I (left) and Lumix G 100-300mm Mk II (right)

Also, it gains weather protection, with one consequence being the rubber gasket around the bayonet mount, seen to the right below:

Lumix G 100-300mm Mk I (left) and Lumix G 100-300mm Mk II (right)

I have put the lenses to the test, to see if there is any real reason to get the newer one.

Focus speed

First, the focus speed. This is a static test, with both lenses on the same camera (Lumix GX7), to see which focuses faster (Lumix G 100-300mm Mk II on the right hand side):

I triggered both cameras simultaneously using a Pixel RW-211 remote control. The video below shows the outcome of the test. First, I test them at 100mm f/4.5:

The focus delay is 0.57s for the Mk I version, and 0.55s using the Mk II version. This difference is barely worth noting, I would say they are equally fast in this test. It was done in somewhat dim indoor lightning.

In the second test at 100mm and 300mm, I test both lenses on a more modern Lumix GH5 camera:

At 100mm, the newer lens is clearly faster, with a focus delay of 0.20s (Mk II) vs 0.25s (Mk I).

At 300mm, though, I repeated the test twice with different lightning, and consistently got about about 30% slower focus with the Mk II version of the lens. This was an unexpected result. I could guess that the newer lens still has a less mature firmware, and that future firmware tweaks may improve this.

Real life use, birds in flight

One typical and challenging way to use a long tele lens, is to photograph birds in flight. This is demanding for the camera and lens, as you will typically leave the focus mode in AF-C, and trust that it gets you the bird in focus when you press the shutter fully to take the pictures.

I had the continuous drive mode enabled with the Lumix GH5 camera, and took the series of pictures under the same conditions.

I used 300mm, f/5.6, 1/640s. Note that when photographing birds in flight, you would normally use a somewhat faster shutter speed, typically around 1/1000s or more. Click for larger images:

Mk I version (focus is generally not good)	Mk II version (barring some motion blur, most are well in focus)

The first thing to note is that I get a faster framerate with the newer lens. This is due to the faster focus and aperture mechanisms. With the older lens, I'd say that the framerate drops to about half.

This is visible in the pictures above, in the sense that I get a longer stream of pictures to choose from with the newer lens. While this is certainly good, please note that the new lens still slows down the camera, meaning that the aperture mechanism of the newer lens is faster, but still not instantaneous.

As for the focus, the bird is much more consistently and accurately sharp with the newer lens. So with the same camera, and the same continuous focus mode, using the newer lens appears to nail the focus better. Again, this means a higher keeper rate.

Even if I was able to photograph birds in flight (BIF) using this combo, I'd say this is still a lot easier to achieve using a traditional DSLR system, at the same price point. So while the Lumix GH5 has taken continuous autofocus to a new level, it is still not nearly as good as a similarly priced DSLR camera, e.g., the Nikon D500.

Here are two more series:

Mk I version (1/4 in focus)	Mk II version (3/4 in focus)

Image quality

About the image quality, I have taken the same pictures using the Lumix GH5 camera at 300mm, f/5.6 and f/7.1. The full picture looks like this:

Here are 100% crops from the centre:

And 100% crops from a corner area:

I think this shows a somewhat better optical performance with Lumix G 100-300mm Mk II.

I only tested the lens at maximum extension, 300mm, since this tends to be the most challenging position for the lens, and it is also the way many will use it: At least I tend to use the lens almost exclusively at 300mm.

Conclusion

The Lumix G 100-300mm f/4-5.6 II is a nice upgrade from the first version. It adds weather protection, and the zoom ring is stiffer, meaning less zoom creep.

When using continuous autofocus on a Lumix GH5, the newer lens gives you a higher framerate, and, in my experience, better focus performance. Both are quite important for sports, birds and wildlife, which I think are key uses for a lens like this.

So, should you upgrade from your Mk I lens? If you are serious about long tele lenses, perhaps you'd rather look into the premium Leica 100-400mm.

On the other hand, the Lumix G 100-300mm f/4-5.6 II does give a real performance improvement compared with the original, and it is still smaller and lighter than the Leica 100-400mm.

While I personally wouldn't trust the weather proofing enough to take the lens outside in rain, the lens is good to bring along while travelling, as it is more likely to survive the dust, sand, and moisture issues you might encounter.

OM-D E-M5 II video quality

The Olympus OM-D E-M5 II is the first Olympus M4/3 camera with a real promise to quality video output. It features 52Mbps output in the "SF" (Super Fine) mode, at 1080p, 60fps (or 50fps if you are in a PAL region country). So how does the video compare with the Lumix GH4, the reference in terms of M4/3 video?

First of all, let's note that there is disappointing news about the E-M5 Mark II video: The sensor is cropped slightly, making your lenses less wide than you expect. Here is an illustration of the sensor area used for video:

This corresponds to an additional crop factor of 1.16. Or in other words, the Olympus 12-40mm f/2.8 becomes 14-46mm when using the video mode. So the effect is not very dramatic.

This crop during video is not uncommon, by the way. The Nikon D7200 can only do 1080p video at 60fps with a 1.3x crop of the sensor. And that is Nikon's premier DX DSLR. While we wait for the D400.

New 20mm f/1.7 lens is less noisy!

The Lumix G 20mm f/1.7 pancake is a classic Micro Four Thirds lens. Being the first Panasonic prime lens, it is widely considered to be very well performing. But it has some shortcomings: Due to the old fashioned focus design, where the whole lens assembly moves back and forth during focusing, the autofocus is rather slow. Also, the large focus assembly makes it very noisy when focusing.

Also, when using the lens on some cameras at high ISO, many users report annoying horizontal stripes. Some believe this is due to a spiral coil spring inside the lens, which is one of the ways in which it is different from other lenses that don't exhibit this aberration.

In 2013, Panasonic updated the lens. It is well known that the new lens is largely a cosmetic redesign: The optical layout is the same, and the focus method is the same. But is the new lens better? The new lens is available in black and silver, and you can see the silver version to the right below:

Old (left) and new (right) versions of the Lumix G 20mm f/1.7

Lens	Lumix G 20mm f/1.7	Lumix G 20mm f/1.7 II
Lens elements/groups	7/5	7/5
Aperture diaphragm blades	7	7
Minimum focus	0.20m	0.20m
Diameter	63mm	63mm
Length	26mm	26mm
Filter thread	46mm	46mm
Weight	100g	87g
Hood included	No	No
Optical image stabilisation	No	No

Autofocus during video comparison, GH2 vs GH3

When the Panasonic GH1 was announced in April 2009, it had a unique selling point: It was the first and only consumer system camera which could autofocus continuously while recording videos. Since this time, the competition has improved a lot, of course, and all mirrorless system cameras can autofocus while recording videos. But they use different technologies, and the performance varies.

The Panasonic GH3 was released with a claim to have the best AF performance of mirrorless cameras ever, as usual for a new premium mirrorless camera. And the AF performance for single still images is very impressive indeed. However, this doesn't really matter. All current Micro Four Thirds camera focus more than fast enough for static still images. Except possibly with the Lumix G 20mm f/1.7 pancake lens, due to its combination of a fast aperture and an old school focus construction.

What's still a challenge, though, is continuous autofocus during video recording, and focus tracking of moving subjects, in AF-C mode.

The Sony SLT cameras solve this by using a fixed translucent mirror, which means being able to use phase difference autofocus (PDAF) also during video recording. This system is able to track moving subjects very well during video, due to the genuine SLR PDAF technology. However, the cameras are not mirrorless, being DSLR systems with fixed mirrors, which means having larger camera bodies, and, usually, larger lenses as well.

The Nikon 1 system and Canon EOS M system solve this by having on-chip PDAF sensors, directly on the imaging sensor. With this technology, they can combine PDAF and CDAF, however, the real world benefits of this system are still undecided.

Panasonic and Olympus have so far used pure CDAF, with no specialized hardware to aid the focusing. They rather rely on image processing to speed up the autofocus. With the Panasonic GH3 being the most recent premium model, let's see if it actually does improve upon the predecessor GH2. To test the cameras head to head, I mounted both on a plank using Manfrotto Superclamps:



On both cameras, I used the Lumix G 14mm f/2.5 pancake lens. The lens focuses very quickly. Even with the same lenses, the GH2 has a slightly wider field of view in video mode, due to the multi aspect sensor feature, which the GH3 misses.

Here are the results in terms of autofocus performance during video recording:



As we see, the Panasonic GH3 performs much better than the GH2 in term of autofocus. Even with the same basic technology, the GH3 has a better image processing capability, which enables it to focus better while recording videos.

Notice that the GH2 needs to jog the focus back and forth to confirm the focus and settle. This is a typical sign of CDAF focus technology. The GH3, on the other hand, appears to nail the focus straight away, as if it was using PDAF. Which it doesn't.

I think it looks like the GH3 is a revolution when it comes to continuous AF during video for Micro Four Thirds. It may be the first camera to make AF during video truly possible.

And this does work well in real life situations. Here, I have recorded a concert using the Olympus 45mm f/1.8 at f/2, ISO 3200. The light was very dim, around EV2. The autofocus was left on during the video, and it generally keeps the image well in focus. In my experience, the GH2 would not have handled such a situation well:



Keep in mind that AF-C while photographing moving subjects is a totally different subject. I would expect the Panasonic GH3 to perform better here as well, as it is capable of AF sampling at up to 240fps with the most recent lenses, the Lumix X 12-35mm f/2.8 and Lumix X 35-100mm f/2.8. However, I have not tested this feature yet.

Autofocus noise comparison

Traditionally, lens focus mechanisms have been rather simple, just a cam which pushes the lens elements back and forth as the focus ring turns. Moving the lens assembly away from the film/sensor gives you a shorter focus distance.

In the Micro Four Thirds family of lenses, this mechanism is rather unusual. Only the two first pancake prime lenses, the Olympus 17mm f/2.8 and the Lumix G 20mm f/1.7 feature this type of mechanism, in which all the lens elements move during focus.

Most other lenses feature internal focus, meaning that only one or some of the lens elements inside the assembly move during focus. This has many advantages: It is usually more quiet, the lens can be more solid since there are no moving elements on the outside, and it is usually less noisy.

On the negative side, this type of focus mechanism can give you a change of effective focal length as the focus moves. This is not much of a problem for still photography, but if you are focusing during video recording, it can lead to what is called "focus breathing", as the image zooms in and out a bit as the focus jogs back and forth.

Focus speed, PL45 vs MZD45

There are two competing 45mm prime lenses in the Micro Four Thirds lineup. The Panasonic Leica 45mm f/2.8 macro lens and the newer Olympus M.Zuiko Digital 45mm f/1.8 portrait lens. While one is a macro lens, and the other could be categorized as a portrait prime lens, they can of course be used for a wide variety of other tasks.

I have previously compared the sharpness of the two lenses in various settings. While the comparisons are not always optimal, and could even be a tad bit misleading, I think it is clear that the Panasonic lens is a little bit better in terms of sharpness. This is not really surprising, since a large aperture lens contains more optical compromises, and usually cannot have the very best sharpness. As a general rule, one does not buy a large aperture lens for the optimal sharpness, but for using it wide open or near wide open, in which case sharpness is usually not the main concern.

People generally say that the Olympus M.Zuiko Digital 45mm f/1.8 features faster focusing. But is it true? The Olympus lens is rated as Movie-Still-Compatible (MSC), which means that the focus speed should be quite good.

I have compared them head-to-head in the same setup. The Panasonic GH2 camera was set up about 60cm from the subject, and I selected centre spot focus. The Olympus lens has a close focus distance of 50cm, and the Panasonic lens has a selectable focus limiter, which cuts off at around 50cm for better focus speed.

When powering on the camera, the lens is focused around infinity. Upon pressing the shutter release button, the camera focuses, and then takes the picture. I measure the time from the camera notes that the shutter release button is pressed, until the camera is ready to expose the image. The first event can be noted by the number of remaining frames being shown in the lower right part of the LCD display, and the latter by the green dot appearing in the upper right corner of the display.

Light background, daylight

Here is the comparison in daylight, the lightning was about EV7.



The focus speeds are rather similar:

PL45, focus delimiter off: 0.32s

PL45, focus delimiter on: 0.32s

MZD45: 0.26s

Dark background, dark room

And another test at EV2, which is very dark:



In this test, the Panasonic-Leica lens focuses faster:

PL45, focus delimiter off: 0.68s

PL45, focus delimiter on: 0.66s

MZD45: 1.12s and 1.08s (two tests)

Conclusion

	light	dark
PL45, limiter off	0.32s	0.68s
PL45, limiter on	0.32s	0.66s
MZD45	0.26s	1.08s, 1.12s

As people have been saying, the Olympus M.Zuiko Digital 45mm f/1.8 lens is indeed faster in terms of autofocus. But only by a small margin. And in dark conditions, to my surprise I found that the Panasonic-Leica 45mm f/2.8 lens focused faster.

This is just some few simple measurement, and in practical use, the experience might be different. During the time I have used both, I have generally found that the autofocus speed is comparable between them for practical, daily use.

Generally, the speed readings here are quite good. I have previously seen that the Panasonic kit zoom lenses achieve focus speeds of around 0.17s to 0.33s under similar conditions. But keep in mind that a much higher degree of focus accuracy is needed for a large aperture lens at f/1.8 than the kit zoom lens at 42mm f/5.6. With this in mind, a speed reading of 0.26s is in fact a very good achievement.

For video use on the Panasonic GH2, it is my opinion so far that the Olympus 45mm f/1.8 is better at keeping the autofocus correct during video capture. With the Panasonic 45mm f/2.8 lens, it generally takes more time before the focus is reached when there is movement in the image frame. But this is just my feeling so far, I haven't examined it in a scientific way.

The Olympus lens also appears to have a more silent autofocus operation.

AF comparison: Lumix 20mm vs Sigma 30mm

I previously compared the Lumix 20mm f/1.7 pancake lens with the Sigma 30mm f/1.4. The Sigma lens was put on a Pentax K10D. While the comparison is not entirely fair, since the K10D is an older camera, my conclusion was that the Lumix 20mm lens was a better performer.

In this article, I am comparing the lenses again. I set the Lumix 20mm pancake lens on a Panasonic GH2 camera, and the Sigma 30mm f/1.4 lens goes on a Pentax K10D camera.

The Sigma 30mm f/1.4 (left), and the Lumix G 20mm f/1.7

Here you can see both cameras set on tripods, pointing towards a LEGO figure on a table. Both cameras are set to f/2.8, and base ISO. I raised the built in flash on both cameras, and set the initial focus to infinity. The focus mode was centre point.

Here's a video showing both cameras' shutter releases being pushed fully at the same time:



Not surprisingly, the Panasonic setup fires off first. It has the fastest autofocus.

With the Panasonic camera, focus was reached after 0.4 seconds, and the pre-flash was fired after an additional 0.17 seconds. There is a pre-flash to measure the required intensity of the main flash, since the TTL flash metering does not work in the same way as with older SLR film cameras. The main flash was fired after a total of 0.77 seconds since the shutter release button was pressed the first time.

With the Pentax camera, I don't have the measurement of the time until focus was reached, since this is not displayed. But the main flash went off after 1.10 seconds. The pre-flash was fired around 0.1 seconds before the main flash.

Now, let me be the first to say that this comparison is unfair. The Pentax K10D camera is from 2006, while the Panasonic GH2 was launched in 2010. Also, I'm using a third party lens on the Pentax camera, which is known to not always give the best AF performance.

The Sigma lens is operating closer to it's minimum focus distance, which is 40cm. The Lumix 20mm lens, on the other hand, has a more generous minimum focus distance of 20cm.

Let's look at the images. Here are the full images, scaled down and resharpened a bit:

Lumix 20mm, f/2.8, base ISO	Sigma 30mm, f/2.8, base ISO

To better compare the images, here are 100% views from the centre, directly from the out of camera JPEG files. These are unsharpened. Click for a larger view.

It is apparent that the the Lumix 20mm lens is much sharper. Also, the Panasonic exposure is better. This is a tricky situation for a DSLR to expose, anyway. The camera has no way of knowing that the white surface is supposed to be white, and not grey. So in this case, I should have helped the camera by saying that it should over expose. The Panasonic camera sees the whole picture prior to making the exposure, and the automatic exposure is clever enough to see that the surface should in fact be white.

When looking at the 100% crops from the two different cameras, one could conclude that the Pentax/Sigma image is unsharp due to front-focusing or back-focusing. I.e., that the AF sensor or lens is not calibrated correctly. Since I am stopping down to f/2.8, though, I doubt that poorly calibrated focus is the reason for the unsharp image. But perhaps it is, and this kind of uncertainty is common when using DSLRs. Thankfully you don't need to worry about it with Micro Four Thirds.

Micro Four Thirds cameras use Contrast Detection Autofocus (CDAF) to verify the correctness of the focus, and it is generally more accurate than Phase Detection Autofocus (PDAF), used on DSLR cameras.

I am confident that the Pentax/Sigma combination focused on the LEGO figure, and not on the background. If I set the camera with the figure slightly off-centre, it would not focus at all, since the white table is too even and glossy.

Conclusions

This study reveals several interesting issues. First of all, we see again that the the Lumix G 20mm f/1.7 pancake lens is very sharp. It's autofocus is not quite as fast as other Micro Four Thirds lenses, however, it is still fast enough for most uses. All in all, it is a very good lens, especially for environmental portraits.

Again, I see that the Sigma 30mm f/1.4 is not very sharp. This disappoints me, since it is otherwise a very interesting combination of focal length and aperture for use on an APS-C DSLR. Some might suggest that my camera/lens combination requires calibration. Perhaps they do, but again, this just illustrates one of the drawbacks with DSLR cameras and PDAF technology.

Some would say that the Sigma 30mm f/1.4 lens is not intended to be very sharp anyway. Rather, it is designed for available light photography of people, to be used with apertures around f/1.4-f/2, say. In these settings, the quality of the bokeh (out of focus rendering) is also important. One could say that the Lumix 20mm lens is more of a generalist lens. Still, I think it's bokeh is usually adequate.

The autofocus performance of the Pentax/Sigma combo was better than I had expected. On the other hand, it is also significantly more noisy. Keep in mind that the Lumix 20mm lens is one of the most noisy Micro Four Thirds lenses I have tried, but the Pentax/Sigma still makes much more noise.

The GH2 camera has a flash lag of about 1/4 to 1/3 second. This is due to the fact that the TTL flash metering does not work during the main flash, like with older SLR film cameras. So to figure out how large the main flash exposure needs to be, the camera does a pre-flash. After having evaluated the pre-flash exposure, the main flash is fired.

1/3 second flash delay is in fact significant, and this is one of the drawbacks of Micro Four Thirds. Note that this is not just related to the built in flash. An external TTL flash, like the Panasonic FL360 also has the flash delay in TTL mode. To avoid the flash delay, you will need a flash that can do traditional flash auto mode. This is a bit more cumbersome to use, and may require some calibration from situation to situation. But an advantage is that you can use just about any flash for this purpose, even if it is an older flash from a different system. Just be sure the flash trigger voltage is not so high that it fries your camera.

Note that the flash delay is not exclusive to Micro Four Thirds. DSLRs also have it, like the Pentax K10D in my example above. However, since DSLRs will use the exposure sensor for the flash evaluation, rather than the main imaging sensor, the pre flash delay will usually be quite short.

AF speed, GH1 vs GH2

I have previously checked the AF speed of the Panasonic GH1, and the Panasonic GH2. However, the tests were done at different times, and with different setup, lightning, etc. Also, the GH1 firmware has been updated in the mean time. So I decided to check both cameras again, under exactly the same conditions.

Again, I set a LEGO figure in the centre of the image frame, and found the time from pressing the shutter release button to the camera taking the image. I turned on the camera just before testing the autofocus, which means that the focus is near infinity when first pressing the shutter release button.

I did the test under two different conditions. The first was in dim light, with a black background: There is artificial lights, and rather dim at around EV5. The distance from the camera to the LEGO figure was about 0.6m.

The second was with daylight coming in through the windows, and white background. The lightning was about EV9.

Here are a couple of examples:



Panasonic GH1, Lumix 20mm, dim lights, black background



Panasonic GH2, Lumix 20mm, dim lights, black background



Panasonic GH1, Lumix 14-140mm @ 140mm, daylight, white background



Panasonic GH2, Lumix 14-140mm @ 140mm, daylight, white background


And these are the timings I found:

Lens	GH1, dim	GH2, dim	GH1, daylight	GH2, daylight
Lumix G 14mm f/2.5 pancake	0.43 seconds	0.43 seconds	0.37 seconds	0.20 seconds
Lumix G 20mm f/1.7 pancake	0.57 seconds	0.53 seconds	0.53 seconds	0.40 seconds
Leica Lumix DG 45mm f/2.8 macro	1.07 seconds	0.93 seconds	0.73 seconds	0.43 seconds
Lumix G 14-42 @ 14mm	0.43 seconds	0.33 seconds	0.30 seconds	0.20 seconds
Lumix G 14-42 @ 42mm	0.47 seconds	0.40 seconds	0.37 seconds	0.20 seconds
Lumix G HD 14-140 @ 14mm	0.40 seconds	0.33 seconds	0.27 seconds	0.17 seconds
Lumix G HD 14-140 @ 50mm	0.53 seconds	0.57 seconds	0.40 seconds	0.23 seconds
Lumix G HD 14-140 @ 140mm	0.70 seconds	0.53 seconds	0.50 seconds	0.33 seconds

What we see here, is that the timings are remarkably similar in the tests done with dim lights. The GH2 has a small advantage to the GH1, especially with the fast focusing zoom lenses. But in this test condition, there is little to gain by using the GH2.

On the other hand, when testing the cameras with more light available, the difference is larger. The GH2 really excels in this test condition.

My previous test gave a larger difference between the two cameras. However, the GH1 firmware has been upgraded several times since that test, and so has the lens firmware. It seems that the GH1, with the up to date firmware, is still very capable.

As for the accuracy of the focus, it is very good with both the GH1 and GH2. Both cameras use CDAF (contrast detection autofocus). This means that the image sensor checks the actual image for focus before the camera takes the picture.

In contrast to SLR cameras, which use PDAF (phase detection autofocus). This means that there are separate AF sensors behind the mirror, which check the focus in some spots in the frame. These sensors must be calibrated to the image sensor, a process which is costly and complicated. Users of SLR cameras often worry that the camera/lens combination is back-focusing or front-focusing, i.e., that the AF sensors are noe correctly calibrated. This is something that users of Micro Four Thirds don't need to worry about.

Modern DSLRs can also use CDAF, which is generally refered to as "live view". However, this focus mode is often quite slow on DSRLs, since few lenses are optimized for CDAF. All native Micro Four Thirds lenses, and some Four Thirds lenses, are optimized for CDAF.

GH1 vs GH2: AF during video

When the Panasonic GH1 was launched, it was the only consumer system camera to provide continuous autofocus during video recording. Since this time, several competitors have launched their own systems, with the same capabilities. To regain the throne, Panasonic's most recent GH2 model must improve upon the original GH1. How does it fare?

To test this, I made a LEGO contraption which moves a paper sheet back and forth. The paper sheet has a printout of a sharpness test pattern. Here's how it looks:



But filming this and seeing how well the camera AF can keep up, we can compare the performance of the GH1 versus the GH2.

Lumix G HD 14-140mm

I set the camera up with the Lumix G HD 14-140mm superzoom lens at f=100mm. My experience shows that the lens performs best in terms of AF in the shorter focal lengths, so setting it at f=100mm is extra challenging. Both cameras were left in iA (intelligent auto) mode. Both were filming in 25 fps, 1920x1080 pixels

The camera was mounted to a tripod, not entirely perpendicular to the paper. That way, the test pattern can be seen to move a bit sideways, and not only back and forth.

Here are the results:



Panasonic GH1



Panasonic GH2

Based on these videos, it's easy to see straight away that the GH2 can keep up the focus in a better way. However, I wanted to check more thoroughly. So I studied the frames to see which were reasonably in focus.

What I found, was that the GH1 cannot keep up the focus at all. Rather, only the frames in which the paper is close to the initial position are in focus. The rest are out of focus.

The GH2, on the other hand, manages to follow the sheet's motion. The frames in which the paper moves most quickly are out of focus, but the camera regains focus when coming near the end-points, in which the paper sheet moves more slowly.

Based on my simple study, it is clear that the GH2 continuous autofocus is better than that on the GH1.

Lumix G 45-200mm

Using the Lumix G 45-200mm f/4-5.6 lens at 100mm gave the same result:



Panasonic GH1



Panasonic GH2

It looks like the GH1 with the Lumix G 45-200mm f/4-5.6 keeps up the focus a little bit better than with the Lumix G HD 14-140mm. This is consistent with my previous experience, in which I found that the 14-140mm is a bit slow to focus in the longer part of the zoom range, and that the 45-200mm is very fast except in the very longest end.

Leica Lumix DG 45mm macro

I also did the same experiment with the Leica Lumix 45mm f/2.8 macro lens. However, the lens was not able to keep up the focus with either camera. It is clearly not as fast focusing as the Lumix G HD 14-140mm lens.

Comparison: GH1 and GH2

When I first got the Panasonic GH1, I noted down some improvement areas for the camera. While it was a good camera, there where many areas where I felt it could be improved. Upon getting the GH2, I am happy to note that many the items have been ticked off.

Panasonic GH1 (left) and GH2 (right)

Some of the items I wrote down were very unrealistic, like implementing in body image stabilization. Panasonic have chosen their strategy, to implement image stabilization in some lenses only, not in the camera bodies. So this is not going to happen.

But a lot of other areas have improved. Here are some examples from my list:

• The control wheel has been moved to the rear side, which I prefer.
• The built in flash has become taller (as can be seen in the images below), meaning that the premium kit lens Lumix G HD 14-140mm casts a smaller shadow when using the flash.
• The new camera does feature a simplified focus scale in the display when focusing manually with a Micro Four Thirds lens. This is not an absolute focus scale with measurements, but it tells you if you are moving towards the close or far end of the focus scale, for example.
• The camera can autofocus with more Four Thirds lenses. For example the Olympus Four Thirds 50mm f/2 1:2 macro. However, the focus is slow for some of these lenses.
• When using legacy lenses, you can access the magnified focus assist view by pressing the rear control wheel. On the GH1, you needed to press two keys to get this mode: First the left arrow key, followed by the down arrow key.

There are also some development areas that remain. For example, the buffer clearing speed is very slow when recording both JPEG and RAW images.


Physical appearance

The basic shape remains very similar. The shell has been made from a different plastic material with a "crinkle" appearance. While the majority of the GH1 body was covered with a rubber-like covering, the shell of the GH2 is more slippery.

On the other hand, the GH2 gains a more solid rubber grip. Somehow, I find that the rubber-like surface of the GH1 feels safe to operate: The camera is less likely to slip out of your hands. On the other hand, the GH2 has a better grip area for the right hand.

Some people have reported that early versions of the G1 had the rubber surface peeling off. This caused negative publicity for Panasonic, and may be the reason why they have chosen a plastic surface without the rubber coating for the GH2.

On the rear side, we can note some changes. The GH2 (left) has a more pronounced frame around the LCD, which I suppose is good for protection. The red video record button had to be moved to the top-side, since the space it previously occupied is now taken up by the thumb wheel.

A subtle, but good change, is that the display button has become flatter. On the GH1, it was easily pressed by a mistake, and now this is not a problem anymore.

From the side, we can see that the SD card compartment has been moved a bit inwards into the camera. My speculation is that this was needed to fit the extended processing power in the GH2 camera.

This placement makes the card a bit more awkward to extract: There is little space for your finger between the card and the compartment door.

As a consequence of the new SD card placement, perhaps, the battery needs to be slimmer. The GH2 battery (DMW-BLC12, left) is new, which has angered some fans. This means that you can not reuse your extra GH1 battery (DMW-BLB13) for the GH2.

In this view, we also see that the tripod mount has shifted backwards.

In this side view, we see that the new flash is taller, which is very good news. Ideally, the built in flash should be as far from the lens as possible, when extended.

Video quality

The GH1 was marketed as a hybrid stills and video camera, the first in it's class to have continuous AF during video recording. In the mean time, some competitors have launched their systems. So to regain the throne as the best video enabled system camera, the GH2 must excel in video quality.

My experiments so far indicate that the GH2 does indeed provide better video quality. I devised a simple test to compare the GH1 (hacked) with the GH2 in otherwise identical settings.

What I found was that the white balance and saturation of the GH2 is more pleasing, and also that the sharpness of the video is probably a tad bit better. But in my opinion, there was not a dramatic difference.

The GH2 features a much appreciated ETC (Extended Tele Conversion). This is essentially a digital zoom that works during video recording. So your lenses become 2.6 times longer, and you can still record at full HD 1080 resolution.

I've also checked the rolling shutter properties of the two cameras. I found that they were mostly identical in this respect. The GH2 might be slightly better.

Anyway, rolling shutter artifacts is not a huge problem with the GH1 and GH2 cameras. Unless you deliberately generate the artifacts, you're very unlikely to find this being a problem. This is in contrast to the Samsung NX10, which I found had significant rolling shutter artifacts.

Autofocus speed

While I had no problems with the autofocus speed of the GH1, I am still happy to see that they have further improved with the GH2.

I'm especially happy that the autofocus has improved when using the Lumix 20mm f/1.7 pancake lens, which felt a bit sluggish on the GH1. Here is a summary of my AF speed readings.

The GH2 appears to be better at continuous autofocus too, according to my test.

Taller built in flash

As mentioned above, the GH2 has a taller built in flash. In theory, this should be good for several reasons: Keeping the built in flash as far away from the lens as possible is generally a good idea. It makes the lightning more flattering when photographing people.

Also, it is a known fact that the GH1 built in flash casts shadow when using the premium kit lens Lumix G HD 14-140mm. Here's how the shadow looks using GH2 (left), and GH1, both at 14mm and having the lens hood attached.

GH2	GH1

As you can see, the GH2 flash reduces the shadow cast a tiny bit, but the difference is rather subtle. On the other hand, you would probably not use the flash at 14mm focal length and 1 meter distance very often. And increasing either will reduce this problem. So for real life use, this is not that much of an issue.

Mirrorless cameras, like the GH1 and GH2, typically require a pre-flash to measure the intensity of the flash. This takes some more time than with DSLRs, since mirrorless cameras don't have a light sensor. They use the imaging sensor as a light sensor.


Battery life

Compared with most DSLR cameras, the battery life of the GH2 is not very impressive.  This is due to operating in live-view all the time.  DSLR cameras don't need the LCD for viewing during SLR mode, and save power that way.

With freshly charged battery, I found that I could record 144 minutes of video before needing a recharge.  This was with the LCD display on all the time. Using the EVF rather than the LCD probably gives better battery life.

It is possible to buy third party batteries for around US$20, but they give some reduced functionality.

GH2 touch screen AF (superzoom example)

I've previously tested the touch screen AF of the GH2, using the 45mm macro lens.

Here's another example using the touch screen AF with the Lumix G HD 14-140mm superzoom lens. The lens was set to 100mm focal length.



As you can see, the response is still somewhat slow, but the actual focus action of the lens is faster than when using the Lumix Leica 45mm f/2.8 macro lens.

I'm using the A mode on the mode dial. Using the iA mode typically gives me the focus tracking mode, in which the response time from touching the screen until the focus changes is a bit shorter.

When using the shutter button to trigger focus, the focus is very responsive, just like in my study of the GH2 autofocus speed.

When recording videos, you can change the focus areas using the touch screen as well. The response and speed is similar to this example.

I have also made an analysis of the focus speed of the GH2 for a number of lenses, and compared with GH1 for some of them.

Panasonic GH2 autofocus speed

Update: Since this test, I have compared the GH1 and GH2 head to head under exactly the same conditions.

I have tested the autofocus speed for the Panasonic Lumix GH2 with various lenses. The test was done by turning on the camera (which leaves the lens at near infinity focus), and then pressing the shutter to see how long time it takes to reach focus. This was filmed using a GH1, and I played back the video in a video editing software, to read out the timings.

There is fairly dull indoor lightning. The lightning corresponds to around EV 6, the same as in my previous test of the GH1. A LEGO figures is placed in the middle of the camera frame, at around 45cm distance. The focus mode used is centre spot.

Here is an example test. In this test, I have the Olympus 9-18mm f/4-5.6 Four Thirds lens mounted to the camera, using an adapter. (Not to be mistaken with the Micro Four Thirds version of the lens.)



This combination gives a rather slow autofocus.

Another example using the Lumix G 14mm f/2.5 pancake:



As you see, the Lumix 14mm lens focuses very fast.

Another example, using the Leica Lumix DG 45mm macro:



This lens does not focus as fast as some of the other lenses, but it's still fair to say that the focus is not slow.

Summary

Here are the timings. I have included a column with the similar autofocus times for the GH1. You should note that the GH1 timings were done with early camera and lens firmware. Later firmware have improved the AF speed.

Lens	Focus time GH1	Focus time GH2
Lumix G 8mm fisheye	Not tested	0.24 seconds
Lumix G 14mm	Not tested	0.20 seconds
Lumix G 20mm	1.23 seconds	0.44 seconds
Leica Lumix DG 45mm macro	Not tested	0.60 seconds
Lumix G 14-42 @ 14mm	Not tested	0.28 seconds
Lumix G 14-42 @ 25mm	Not tested	0.20 seconds
Lumix G 14-42 @ 42mm	Not tested	0.44 seconds
Lumix G HD 14-140 @ 18mm	0.53 seconds	0.16 seconds
Lumix G HD 14-140 @ 50mm	0.40 seconds	0.40 seconds
Lumix G HD 14-140 @ 140mm	0.68 seconds	Not tested
Lumix G 45-200 @ 45mm	0.33 seconds	Not tested
Lumix G 45-200 @ 100mm	0.36 seconds	Not tested
Lumix G 45-200 @ 200mm	0.87 seconds	Not tested
Olympus ZD 4/3 9-18 @ 9mm	2.90 seconds	1.44 seconds
Olympus ZD 4/3 9-18 @ 18mm	1.50 seconds	1.36 seconds
Olympus ZD 4/3 50mm f/2	No AF	4.76 seconds

Conclusions

What we can see, is that the GH2 autofocus speed is very good. The Four Thirds lenses used on adapter are still slow, but they behave better. The Olympus 50mm f/2 macro lens can actually autofocus on the GH2, but the speed is very, very slow. It could be used for stationary objects, but for photographing people, the AF is more or less useless.

The Panasonic Lumix GH1, and the whole first generation of Panasonic G cameras, could not autofocus with the Olympus Four Thirds 50mm f/2 macro lens. This also applies to a host of other Four Thirds lenses that are not optimized for CDAF. The newer GH2 can autofocus with most Four Thirds lenses. However, the focus can be rather slow, as we have seen in this example.

Even the Four Thirds Olympus 9-18mm f/4-5.6 wide angle zoom lens, a fairly recent CDAF optimized lens, has an annoyingly slow autofocus. The AF is usable, but not as fast as we have become used to.

I am also rather happy that the autofocus speed for the Lumix 20mm f/1.7 pancake lens has improved a lot with the GH2. After all, this is a very good lens, and I find the AF speed to be important when photographing people.

As expected, the Lumix G HD 14-140mm superzoom lens remains very fast in terms of AF. It seems that the close focusing range differs for various focal lengths. The close focus range is specified at 50cm, however, it can focus a bit closer in the wide end of the zoom range. I was not able to test the lens in the longer range this time, since it would not reach focus there at 45cm distance.

The new kit zoom Lumix G 14-42mm is also a very competent lens when it comes to focus speed. I think this was to be expected, after all, it is a brand new kit lens, and focus speed is one of the important factors when people buy camera kits.

Four Thirds lens compatibility

Panasonic Lumix Micro Four Thirds (MFT) cameras can use all Four Thirds (FT) lenses, provided that you use an adapter. You can use either the Panasonic DMW-MA1, or Olympus MMF1/MMF2 adapters.

However, you should note that not all FT lenses will autofocus on Panasonic MFT cameras. Only fairly recent lens designs that are prepared for contrast detection auto focus (CDAF), will work. The compatible FT lenses are

• Olympus Zuiko 25mm f/2.8 Pancake
  
• Olympus Zuiko 9-18mm f/4-5.6
  
• Olympus Zuiko 14-54mm f/2.8-3.5 II
  
• Olympus Zuiko 14-42mm f/3.5-5.6
  
• Olympus Zuiko 40-150mm f/4-5.6
  
• Olympus Zuiko 70-300mm f/4-5.6
  
• Panasonic Leica D Summilux 25mm f/1.4 Asph
  
• Panasonic Leica D Vario-Elmar 14-50mm f/3.8-5.6 Asph Mega O.I.S.
  
• Panasonic Leica D Vario-Elmar 14-150mm f/3.5-5.6 Asph Mega O.I.S.

These lenses will autofocus on Panasonic Lumix MFT cameras, like G1, GH1 and GF1.

Newer Panasonic cameras like GH2, G2 and G10 feature some improved autofocus functionality using some FT lenses. For example, the GH2 can autofocus using the Olympus 50mm Four Thirds lens, but the focus is very slow. The Panasonic G1, GH1 and GF1 will not autofocus this lens at all.

All Olympus MFT cameras can autofocus with all FT lenses, so Olympus camera users can ignore this list. This also goes for Panasonic FT lenses used on Olympus MFT cameras. The autofocus can be very slow with some FT lenses, though.

For those combinations of lenses and cameras where autofocus works, you will still experience slow autofocus with FT lenses on both Panasonic and Olympus MFT cameras. I have made a comparison of autofocus speeds using some MFT and FT lenses on the Panasonic GH1. Also, a similar comparison for the Panasonic GH2.

Even if autofocus does not work on some camera/lens combinations, other functions like aperture control will still work. And using manual focus is not that difficult. Here is an illustration of using manual focus with Olympus 50mm f/2 macro on Panasonic Lumix GH1.