FrameFarmMedia
Veteran
The AF100 was the first large sensor camcorder. Until this year NO large sensor camcorder had a servo zoom.
GH2 Native GH3 I-Frame 72Mbs Video
- Thread starter TheDingo
- Start date
The AF100 was the first large sensor camcorder. Until this year NO large sensor camcorder had a servo zoom.
I see your point, but that's still more of a 'compression' artifact than an 'I-frame' artifact.
Barry_Green
Moderator
You are kidding, right?
Who makes a large-sensor video camera that isn't a half-assed DSLR? Until the AF-100, nobody did.
The AF100 was made and marketed as a CINEMA camera. They never claimed it could do events. And as an ex-events shooter, there's no way that the AF100 would be my first choice for shooting events! Why would it be, when there are literally DOZENS of cameras on the market that are designed to excel at that purpose?? The AF100 was something NEW, something we'd never had before.
If it doesn't work for you, then that's okay -- but it sure doesn't mean there's anything "wrong" with it!
That doesn't make it OK to drop such a standard feature as servo zoom. Newer technology should add features, not get rid of them.
Barry_Green
Moderator
There are two Lumix power-zoom lenses, a 14-42 and a 45-175. They work with the AF100 through either the rocker switch on the lens, or through the remote control. And yes, that does mean the AF100 was the "first" large-sensor camera to offer a power zoom option.
Barry_Green
Moderator
Good heavens -- was it okay for pickup trucks to drop such a standard feature as the back seat? Of course it was, because a pickup truck isn't a car -- it's a pickup truck!
If you don't understand what a cinema camera is, that's okay -- just move on. But please stop complaining because a pickup truck isn't a convertible sports car. They're two entirely different things.
Better bokeh.
My comments about Panasonic messing up the AF-100 were qualified as being from my "event shooters" viewpoint, and were only posted to show that it is possible for Panasonic to disappoint a generally happy customer with a new model camera. They don't always get it right.
That's a bad analogy and here's why. If you design the camera for event work, it will be equally well suited for production work. But cameras designed for production work often leave out features necessary for event work.
Besides, you'll notice they eventually returned the back seat to pick-up trucks, and now it can serve both customers, the family man and the hauler.
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Got you. I actually own the 45-175. I'll probably return it because it just doesn't get wide enough, and it's not mechanically driven in manual mode.
Still, lenses along that line of thinking should have gone to market simultaneously with the release of the AF-100, not two years later. And really, would it have killed Pany to add the standard hand-grip rocker for such a lens?
Thomas Smet
Veteran
Except that was a brand spanking new product. The GH3 is a third generation upgrade of a tried and true product line.
LanceOregon
Well-known member
Cats are readily available worldwide, so they make a most excellent standardized test subject to shoot.
Barry_Green
Moderator
Absolutely not true. A 1/3" camera with an optically-image-stabilized lens and deep DOF is INFINITELY better suited for event work than a large-sensor, interchangeable-lens camera. Period.
yes, of course they do. Look at the BMC -- you'd have to be unhinged to think about shooting events on that. Cinema cameras are made for cinema work. Event cameras are made for event work. When you try to be everything to everyone you inevitably end up being nothing to anyone.
That's true. But there are just so many technocrats doing so may things wrong that probably nothing could fully eliminate my fears that any new product or version will also do something wrong.
Well, I agree I wouldn't want Joss shooting The Avengers on the DVX100, but plenty of folks have had no trouble shooting documentaries, corporate jobs and other productions using 1/3" cameras for the past decade or so. I'd wager even you've shot a production or two on a DVX100, eh?
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Thomas Smet
Veteran
Same difference really. Most video codecs are built off the same DCT image compression concepts as jpeg image compression. Video codecs just take it to a whole new level with interframe compression. An intraframe codec however is really not all that much different then a series of jpegs.
Take a look at Apple ProRes for example. All forms of ProRes are intraframe but yet ProRes Light can have more per frame artifacts then ProRes High. This is usually in the form of mosquito noise or blotches. Back when I created a mpeg2 intraframe plugin for Avid Liquid I found 150mbits to be the safe area for clean full HD. 100mbits was ok but it started to see the exact same artifacts as Apple ProRes at the lower levels. 72mbits could be done but it would have more of a chance of image based artifacts in busy scenes. Now AVC does have a few helpers that help in per frame image compression and the GH3 also only uses 4:2:0 which really does help a lot. I'm willing to bet however the same sample on Vimeo would not have looked as clean if it were shot at 60p instead. Is that even an option for the 72mbit mode?
Thomas Smet
Veteran
I have done crazier things on a production. lol Then again my wife does think I'm unhinged.
We'll leave those out of it for now, using the idea of a "Cinema camera" as something capable of shooting at a quality suitable for Hollywood. I'm talking about event and production work, neither of which ends up at your local cineplex.
But on the subject of Cinema cameras, the Holy Grail (for me, at least) is to make my events look every bit as good as what I see on the big screen. I may never actually get there, but it becomes frustrating when cameras that are capable of that quality are released at a price point I can afford, but I'm still held back by missing features that have been standard on pretty much all cameras at this price point for a long time now.
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The first two GH3 video files I've examined reveal some interesting details. The AVCHD file is a 1080p50 28Mbps MTS file. The H.264 file is a 1080p50 50Mbps MOV file. Both files have the following properties:
The AVCHD encoders used in the GH1 and GH2 were only able to use 4x4 quant matrices. The extensive use of 8x8 matrices (as well as 4x4) in both AVCHD and H.264 GH3 files indicates a major upgrade to its encoder. If it works as efficiently as H.264 encoders used in other DSLR's, the GH3 encoder should be able to produce high quality images using significantly less bitrate than a hacked GH2 requires.
- High 4.2 profile in 8-bit 4:2:0 color depth
- 24-frame GOP with standard IBBPBB structure
- Both 8x8 and 4x4 quant matrices used in I, P, and B-frames
The AVCHD encoders used in the GH1 and GH2 were only able to use 4x4 quant matrices. The extensive use of 8x8 matrices (as well as 4x4) in both AVCHD and H.264 GH3 files indicates a major upgrade to its encoder. If it works as efficiently as H.264 encoders used in other DSLR's, the GH3 encoder should be able to produce high quality images using significantly less bitrate than a hacked GH2 requires.
I guess it's a matter of semantics. When I read "I-frame artifacts", I read that as an artifact that was cause solely by the fact of it being recorded as I-frame, meaning the artifacts would still be there even with plenty of bandwidth, but would somehow disappear if a GOP was used. That just didn't make sense to me, so I queried it.
