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.
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|
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.