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Test footage from the pre-release Panasonic GH3 at Photokina


Andrew Reid

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[quote name='AdRath' timestamp='1348617622' post='19049']


This has to be a troll post right? Alexa B-cam? for $1299? HAHAHAHA!

They didn't listen to complaints? I'd say they answered most of them

-DR
-Build quality
-Weatherproofing
-codec
-1080p 60
- Low light performance
-headphone jack
- Colour

I can't see anything to complain about for $1299.
[/quote]

The price isn't ridiculous... I actually don't understand why everyone's complaining about "that" when everything else is a $1000 more.
I've had a week to stew on my thoughts of the GH3 & honestly, even pre-production firmware aside - there's no footage out there that showcases
These upgraded features! Not one shot in Genesis was longer than 2 seconds at the most & how can anybody interpret a difference at that point? I don't have the Voigtlander 25mm, so I can't say the slow-mo shot of our protagonists' silhouette running down an alley at the camera with one light behind him, (and from what i could tell - no noise) - could've been pulled off with a GH2.... Especially in 60p with a reduced codec.

People want to see the "Extended Dynamic Range" sensor in action, etc. High bitrates are great... If you blow up the footage to 400%, because quite honestly, the Flowmotion patch gets down to 35mbps on certain shots, but it still outshines any 170 + driftwood patch i've used... (However Sedna was great.).
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Man people are really going overboard with this stuff. I can't see why we only want to focus on the images that look bad and ignore the ones where things look GREAT! How do we keep the camera in tha

[quote name='MaxAperture Films' timestamp='1348313715' post='18893'] Looks like the greenish cast is just as bad if not worse on the Genesis BTS video (shot on GH2) [media]http://vimeo.com/49500954[

"I’d happily pay $3000 for this [better image in the next, upcoming camera], as the GH3 already is a bargain for $1299". I would NOT. GH3 is a new camera that many are waiting for. It costs mo

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[quote name='sanveer' timestamp='1348743383' post='19108']
The downscaling (for video) isn't really an issue in the GH2. The whole moire and aliasing happens, probably due to some codec issues, where they try and resolve the chromatic aberration (I'm guessing). That is why, it happens with the Panny lenses
[/quote]

I think I see what you're saying. The Panasonic lenses have more chromatic aberration so they try and fix this by using a filter that sums the colors back together and that's what's causing the moire? I don't think this would happen in the compression stage though. I think if this is indeed what's going on, then it would be happening at the initial sampling stage before getting to the codec.

The more I learn about sensor technology the more I realize an interesting parallel between it and "Ray Tracing".Keep in mind that this is just my observations. For those who don't know, ray tracing is a technique to render 3D model and animation data into 2D images. But basically it works on a very similar principal. Aliasing and Moire show up in ray tracing too when you don't employ a good enough anti-aliasing filter. This isn't just a simple filter that looks for edges and tries to smooth them. Instead, while sampling the scene (or in the case of sensors, the original image) you can fire addition rays around around the initial pixel and then take all those color values of the extra pixels (or sub-pixels) and "sum" them together to produce a pixel that better blends with the surrounding pixels. This makes the image appear much smoothers but also retains all the detail of the original image because you are not throwing them out but rather using it to form your final image. This is also referred to as sub or super sampling. I think this is what you guys call "Binning" in relation to the scaling of the full mega pixel image down to an HD image? In ray tracing, the technique you employ to "Sum" the extra pixels into a single pixel is called an anti-aliasing filter. It has a very strong effect on the final image and there are a whole slew of algorithms out there. Gaussian, triangle, box, Mitchell-Netravali, Catmull-Rom etc. How this relates to image scaling is that when you scale an image, you essentially take a group of pixels and "Sum" them together to make a new pixel. This is basically, for all intents and purposes, the same thing as super/sub pixel sampling in ray tracing although, you don't have to use complex math to calculate the color of the initial pixel, you already have it from the original image. And just like in ray tracing, the algorithm you use to sum the pixels together greatly affect the final image.

It would seem that the so called "Line skipping" that Canon and Sony use, is basically just throwing away the ext a data. Which would make sense given the results I see using these cameras. I would assume It takes a lot of processing power to sum/bin (applying a mathematical algorithm to each group of pixels in real-time) all those pixels so it would make sense to use a simpler and faster technique and just do a post filter to smooth out the results while you are smoothing out the noise anyway. The one thing I find funny is that people call this line skipping when I think it's probably more like pixel skipping where you skip ahead in the line in grab a pixel, skip ahead and grab a pixel and so on.

Anyway, Looking at the results of the GH3 footage and compareing it to GH2 footage, it appears to me that they may have changed their anti-aliasing algorithm. On the GH2, the algorithm seems to favor edge contrast (which increases our perception of detail) and may even do a bit of enhancement. The problem is, I can't really tell what's going on with The GH3's aliasing filter and maybe that's their intent. Maybe Panasonic felt that the GH2's filter may have been to strong and noticeable and tried to tone it down a bit or make it more even handed in it's approach to contrast. This might actually help with dynamic range. This might also explain the seemingly lack-luster quality that we are perceiving in these early tests. Also, if the algorithm is tuned to be less noticeable, it might then let more aliasing through the filter and cause moire in the process.

Again, this is only my observation.
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[quote name='quobetah' timestamp='1348326297' post='18906']
After seeing this video, [url="https://vimeo.com/49875510"]https://vimeo.com/49875510[/url] , h.264 cameras dont interest me anymore. I say deat to 4:2:0!!!
[/quote]

Good example. Maybe you rather mean Canon cameras ;) This video is a promotional BMCC flick, but in fact Canon effect is awful.
When it comes to GH3 there is something very useful- [url="http://www.imaging-resource.com/news/2012/09/28/qa-with-panasonic-the-story-behind-the-new-gh3-and-compact-system-tech"]uncompresed HDMI output[/url]. Very good interview, by the way.
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[quote]'DE: Speaking of the HDMI output, can you confirm that the GH3 can stream uncompressed HD video through the HDMI port, for use with an external recorder?

Panasonic: Yes, it isn't compressed. You can turn off all the on-screen indicators, so you can use the GH3 like a video camera with uncompressed 1080/60p HDMI output.'[/quote]

This was possible with the GH2 as well. The video is uncompressed, but it suffers from all artifacts the compressed version has minus -haha- those related to compression. Meaning: No higher DR, still banding, ISO noise, if the GH3 will introduce moire, it won't disappear in a ProRes or DNxHD file captured externally. What uncompressed video renders obsolete are the high bitrate hacks.
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