Saturday, May 26, 2012

Panasonic GH2 impressions

I've now had the Panasonic GH2 for a little under three months and have used it enough to give my first impressions. This is no real review, since I don't do those, but the internet is full of reviews anyway. Dpreview is a good source for those.

My move to the m43 world occurred in August last year and I haven't looked back. For my purposes the size and image quality balance is very suitable. I started with an Olympus E-P2 and liked the camera a lot. It certainly had the hard-to-define fun factor and I certainly think the pictures on this blog from last fall shows that it is a very competent camera. Sometime during last winter I became more interested in video making, and started to investigate the options. A video camera never seemed very interesting for me, since I also wanted it to be a competent still camera. The wish to be able to use a short DOF also steered me away from pure video cameras, since that is not easily achievable with the very small video camera sensors.

I knew of the Panasonic GH2 and had read something about its video capabilities. Some more reading on the internet showed that this actually was one of the best video capable system cameras available. The actual video resolution of the GH2 is much better than that of the other system cameras  (not one comes even close to the nominal 1920x1080 pixels of the FullHD resolution), but the color reproduction are generally considered slightly weaker than that of the Canon EOS cameras. The GH2 was also the best m43 still camera until the Olympus EM-5 came out. However, the Olympus EM-5 was no alternative, because of the lacking video capabilities, even though the camera otherwise in most aspects is superior to the GH2 and has an extremely cool image stabilizer. The GH2 is shaped like a traditional DSLR, but is significantly lighter and smaller. The body (including battery) weigh 453 g, the Olympus 9-18 mm lens shown below is 190 g and the Olympus 14-150 mm lens is 280 g. Compare this to the body only weight of the Canon EOS 60D, 755 g, and the Canon EF 15-85 mm lens, which weighs 575 g. The weight savings of an m43 system is quite large when you bring more than one lens. The EOS 60D has a slightly better image quality than the GH2, but the video quality of the GH2 is noticeable superior.

I decided to purchase the Panasonic GH2 in the end of February. A local camera shop ordered it for me and it arrived one week later. I did a first video with it and the result is found here:

Despite not really knowing the camera and therefore using somewhat suboptimal settings the result is quite good, I think. The technical quality of the video cannot of course be evaluated from Vimeo, because of the low bitrate, but a video generated with full quality is very good technically.

As a still camera, I had some difficulty getting the hang of it. The GH2 contains lots of features and is very different from the Olympus. One positive aspect compared to the EOS 60D is the autofocus accuracy, which is a lot better. The EO 60D occasionally suffered from front- and backfocus problems, since the autofocus sensors are not exactly in the same plane as the sensor. It occasionally affected the images. The GH2 also lacks the in-body image stabilization of the Olympus, which I personally think is a big omission. The image quality is better, though. The resolution is better, as is the high ISO performance and dynamic range.The GH2 also features a sensor allowing multiple aspect ratios without simple cropping like most cameras do. This is possible through an oversized sensor. It took a while to start using this feature efficiently, but now I think it is very nice to have.

Ordinary 4:3 aspect ratio (16 MP).

3:2 aspect ratio (15 MP).

16:9 aspect ratio (14 MP).

The camera has a fairly good EVF (electronic viewfinder. The EVF is big and bright, but the colors are not as good as those of the Olympus VF-2. The LCD on the back can be swiveled and tilted to a lot of different positions, which often comes in handy and is especially useful for video filming.

The video mode is the most interesting part of the GH2, since that is one area where the difference between different cameras is still big. With the firmware 1.1 it got a 24 Mbps 1920-1080 25p mode, which is a lot better than the same video mode of the EOS 60D, despite the 60D having a higher bitrate (and probably poor video compressing software and processors). The real video potential is unlocked by applying one of the unofficial firmware hacks. These hacks reprogram the image processors with different scaling and quantization matrices and raise the bitrate, which enables more details in the video file. The cost of this is the need for faster memory cards and larger video files. I've used the FlowMotion 1.0, Sanity 5.1 and now the FlowMotion 2. In addition to these, there are a lot of parameters that are relevant, like sharpness, noise reduction, saturation and film mode (which affects the tone and color curves). I don't have the time nore the drive to try out all these by myself, but there is a lot of stuff written about it on the internet. You just have to choose a method and stick with it.

Another cool thing with the GH2 is the ETC mode. This is sort of a digital zoom that is of no use when taking stills, but for videos it is great. It just uses the central 1920x1080 pixels of the sensor, instead of reducing the pixels from the full sensor area down to a HD resolution. The result is a strong tele effect, which in good light theoretically could be superior to the ordinary video picture. In poor light noise becomes a problem. This enables closeups in video mode with only moderate tele lenses.

Note that the reduction of the bitrate down to 5 Mbps from 40 Mbps was not kind to this small clip. The details in the feathers of the second Canada Goose are obviously too much for the compression algorithm.

The battery life of the GH2 is not great. On my latest outing, I ran out of batteries the third night (I brought two batteries). I did a fair bit of filming, but I still think the batteries ran out too quickly. I guess I have to order a few more.

I guess there is a lot more to say about the camera, but these are my impressions after almost three months with it.

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