GH2 official discussion thread

My question: can we output to Aja Mini while using the AF? Or only while not recording so we keep all frames but if we do that then the AF will not work. In other words, can we get near the quality of the Af100 with XLR phantom by using the Aja? Obviously the OBPF will not be optimized for video, but will that be essentially all?
 
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Vitaliy Kiselev said:
Look at other menu shots.
They have special modes like native 24p and variable framerates on semarate menu.
Click to expand...
Well, they call it "24p cinema" not "24p native." I really hope that I am wrong.

[update1]
Parsing the PR, we get the following unfortunate disclaimer.

*2 Full-HD (1,920 x 1,080) movies are recorded at 60i (NTSC) / 50i (PAL). HD (1,280 x 720) movies are output and recorded by the image sensor at 60p (NTSC) / 50p (PAL).
Click to expand...
 
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SO, after carefull reading this http://panasonic.net/avc/lumix/systemcamera/gms/gh2/movie.html

Here are my conclusions:
highlight_display_image01.jpg

Digital Zoom is independant function from EX. OPTICAL ZOOM
Ex. Tele Conv is indeed 1:1 mode. It is HUGE!
We have at least 0(OFF),1,2, and 3(100%) microphone level settings.
We have ZEBRA (look at highlighted menu item).
 
Ben_B said:
Tell me this doesn't mean B-frames!
"by checking before/after frames."

Little graphic and all...looks like we have B-frames :)
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I'm not sold on B-Frames yet... an HMC at 17mbps performs much better than 20% over an I/P implementation.

20% could simply be the 17 to 24mbps bump.

...or if it is 24p native, they could just be accounting for the fact that 24 frames is 20% off of 30 (60i), or that progressive frames are more efficient than interlaced.

Vitaliy Kiselev said:
Yes, I think we have not only B frames, but CABAC also ( another 20% savings).
Click to expand...
I haven't seen that anywhere, but it sure would help if it's there.

svecher said:
Well, a properly implemented codec with B-frames may perform quite well at those rates. However, I don't want to be in pessimistic mode today, but the following little picture (courtesy of dpreview)

moviequality.jpg


leads me to believe that 1080/24p mode will be delivered in the same old 60i wrapper. So 20% of bitrate lost to junk data.

I will happily eat crow after running an MTS file shot in "cinema mode" through GH13 parser and discovering it has native 24 fps rate at 24 Mbps avg bitrate (and B-frames present).
Click to expand...

I'm not seeing hard evidence yet, but does seem possible since there it uses a new mode with it's own bitrate. The slow/fast motion modes they would be pretty annoying interlaced, but then again, so is everything interlaced.


It takes a ton of power just to play back HMC files let alone encode them, so I don't think we are going to see the same implementation or they would be bragging about it. I hope I'm wrong, but it seems unlikely with those numbers.

Regardless, there are some great improvements to make it that much better. It's never going to quite a full AF-100, but should give very similar picture quality at a fraction of the cost. Best of all (for the consumer and Pany), one can always upgrade from the GH2 (or other m43 cam) to the AF-100 (or rent) and have their lens collection ready to go.
 
Very interesting interview (in french) with Uematsu Michiharu, Lumix development director at Panasonic:

http://www.focus-numerique.com/test-1044/interview-uemastu-michiharu-panasonic-gh2-1.html

He thinks that:
• phase AF stays better for moving subjects and burst mode
• phase AF integrated in the new Fujifilm sensor is a good system, particularly for video
• 12 megapixels stay sufficient for stills as he said already 6 months ago, 16 megapixels sensor have been a marketing decision...
• for electronic shutter they hadn't enough people and resources at panasonic to work quickly on it (3D has monopolized them) There will be line of products with mecanical and line of products with electronic shutter in the futur.
• 3D lense will only work with G2 and GH-2, not the older models, because they havn't enough intern memory for the 3D algorythms
• as for the mecanical/electronic shutter, they're wasn't enough resources (thank you 3D lenses, camcorders and screens...) to make it better now

Well, as I understand this (good) interview, GH-2 could have been even way better...
 
I agree about memory in GH1 and G1. Remaining flash memory size is too small.
Plus LSI is different and I am not sure that necessary functions are present.
It means only one thing - no more firmware updates for GH1.
 
svecher said:
Well, they call it "24p cinema" not "24p native." I really hope that I am wrong.

[update1]
Parsing the PR, we get the following unfortunate disclaimer.

*2 Full-HD (1,920 x 1,080) movies are recorded at 60i (NTSC) / 50i (PAL). HD (1,280 x 720) movies are output and recorded by the image sensor at 60p (NTSC) / 50p (PAL).
Click to expand...
Click to expand...

Note that the *2 comes after the 60i talk. The next sentence separately talks about the 24p native mode, which sounds promising.

Now the DMC-GH2 can record high-resolution full-HD 1920 x 1080 movies in astonishing smooth 60i, doubling the sensor output from 25p/24p to 50p/60p.*2 The DMC-GH2 also supports 1080/24p native mode with 24 Mbps, the highest in AVCHD format bringing impressive afterimage to the movie.
Click to expand...

One thing is for sure, companies LOVE to confuse the hell out of consumers when it comes to HD. Putting "60p" in their press releases seems to be a marketing ploy for the uneducated... though maybe it's just that the people writing it don't understand the differences either :)
 
Adventsam said:
on a 2gb file in avc at 17mbs, its more like 20+mb/sec, also the 24mbs is 10mins, this seems right.

look at the specs, my bet is the 1080i is much higher 21mbs, more as an avg possibly.

http://panasonic.net/avc/lumix/systemcamera/gms/gh2/movie.html
Click to expand...
For the HMC, it is typically lower because it is VBR, meaning it can put more work into the busy frames.

A fixed bitrate of 24mbs would be more ideal for this camera, esp if it does not have B frames... but we can only speculate until files are released.
 
Just curious what is the 1:1 ext zoom? Is this different than the GH1s digital crop option? I have some lenses, accessories that vignette will this mode solve this? Cheers
 
kainekainekaine said:
Just curious what is the 1:1 ext zoom? Is this different than the GH1s digital crop option? I have some lenses, accessories that vignette will this mode solve this? Cheers
Click to expand...

GH1 do not have any crop function. Only digital zoom that can be done in any video editor.

GH2 mode allow you to use ANY 2/3" lens without vingetting.
Including wide lenses (like cheap 8mm ones).
 
Yes, but the avg bit rate of the GH1

Yes, but the avg bit rate of the GH1

original f/w was always lower than 17. This suggests that the avg is much higher than 17 ie much greater than 20mbs. I am wondering if they are not telling the whole truth and we can expect much better bit rates. ;-)


mcsmooth said:
For the HMC, it is typically lower because it is VBR, meaning it can put more work into the busy frames.

A fixed bitrate of 24mbs would be more ideal for this camera, esp if it does not have B frames... but we can only speculate until files are released.
Click to expand...
 
Is 50i from 50p a lot better than 50i from 25p?

Also will there be limitations in resolution or something else for the tele converter?
 
Man, so disapointed with the frame burst mode (I know not many care for this).

My $500 Casio EX-F1 can burst 60p for 60 frames at 6mpx and the GH2 can only manage a megre 40 frames at 2mpx (in 16:9).

Very poor..... the chipset and buffer in the GH2 could surely manage more...maybe giving us 10 seconds of amazing jpg sequence for certain shots.
 
tcglog said:
Is 50i from 50p a lot better than 50i from 25p??
Click to expand...

Get any camcorder with 50i and compare.
Motion is more fluid, but original progressive frame restoration is impossible.

Also will there be limitations in resolution or something else for the tele converter?
Click to expand...

It has one simple limitation - sensor resolution.
Your focal multiplier will be 2x2,6=5.2
And that is all.
Bunch of cheap 2/3" glass prices will skyrocket in 2011.
So, make investments.
 
Vitaliy Kiselev said:
GH1 do not have any crop function. Only digital zoom that can be done in any video editor.

GH2 mode allow you to use ANY 2/3" lens without vingetting.
Including wide lenses (like cheap 8mm ones).
Click to expand...
Since this is a "teleconverter" though, field of view also changes, so an 8 mm lens will have an equivalent FOV of a 20 mm pancake. Theoretically, this means no aliasing however (if is indeed an 1:1 pixel mode), which is absolutely awesome! I would love to see some resolution tests of this feature ...
 
stockfuel said:
Man, so disapointed with the frame burst mode (I know not many care for this).
Click to expand...

:-)

My $500 Casio EX-F1 can burst 60p for 60 frames at 6mpx and the GH2 can only manage a megre 40 frames at 2mpx (in 16:9).
Click to expand...

Casio is compact with tiny sensor.
And 40fps mode has 4Mp resolution, not 2Mp.
GH1 image quality and SD write rate must be also much better.
 
tcglog said:
Is 50i from 50p a lot better than 50i from 25p?
Click to expand...
No, it's a bad idea. A 50i video stream has only half as much data as a 50p video stream contains. What typically happens is that half of the horizontal scan lines in each 50p frame are discarded...
 
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