GH2 official discussion thread

tipota said:
I do at times shoot additional material for TV, use the GH 13 as 2nd, 3rd & crash-cam for productions and have 25 p material from other video cams that won't intercut with 24 p without producing synchronity problems .... and I am no fan of pull-down removal and other issues.... and I am not sad but a tiny bit upset .... and, as I said, I am out of here.... so: Au revoir.... ;-)
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If you shoot for TV, get a camera that is suitable for that. For the third time, nobody is forcing you to shoot 24fps. You're torturing yourself.
 
mimirsan said:
Because its not a issue for you? This is a FORUM! Discussion,whining whatever you call it is all part of a forum sadly.
Everyone is allowed to express a opinion...yours is taken on board.

It would be mentioned tenfold in these forums if there was no 30p or 24p. :cheesy:
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There is no 30p 24mbps!!! Now who's complaining about that?

Of course it's all free and democratic but what's the strength of a forum if the majority of messages is negative and people with a positive attitude stop reading because they're getting fed-up? There is so much positive to write about this camera and again, for the fourth time, the 25p whiners do have a point but contacting Panasonic directly would have more effect probably. Make some kind of petition and have it electronically signed by a bunch of people and e-mail it to Panasonic UK, Holland, France and Germany.
 
Spectra said:
1080 50i is also half the vertical resolution (540 lines) of 1080 25P
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I dont think this is a good way to present facts? 1080i can give the same number of lines as 1080p - namely 1080. It can also give the same number of fps (50 or 60). This is evident from the fact that properly deinterlacing tru interlaced material means having to do 1080i50->1080p50. The reason why the format has to have double the pixelrate after deinterlacing is the way interlacing works. That is not to say that 1080i50 has as much information as 1080p50 (it does not), it merely tries to seem to in a perceptually sensible manner.

Nowadays we have digital video codecs that does a lot more than 2:1 compression with more predictable performance, so we should not need to do interlacing anymore, in fact interlacing is an issue for most video codecs.
Interlace has been a kludge that had in use once upon a time but should have been dropped from HD spec IMHO.
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Agree

-h
 
mimirsan said:
It would be mentioned tenfold in these forums if there was no 30p or 24p. :cheesy:
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The GH2 does not offer 1080p @ 30 FPS in any native form. I haven't heard even one complaint about that. I really wish the GH2's 1080i mode was like Sony's 1080i PSF @ 30 FPS mode. That is much more useful.
 
hjulenissen said:
I dont think this is a good way to present facts? 1080i can give the same number of lines as 1080p - namely 1080.

Agree

-h
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Wrong, the only way to get a 1920x1080 image from 1080i is to interpolate in 540 lines of vertical resolution. It has the same 1920 lines of horizontal resolution but it is missing every other line of vertical resolution. This is true for converting 1080i to 30 FPS or 60 FPS. It simply does not have 1080 vertical lines of resolution.

The scalers today can be very good and produce astonishing results. However, it is still scaling. It is the same as saying my GF1 videos are 1080p because I used a super computer to scale them from 720p to 1080p. They may look similar to 1080p but they are still just scaled 720p.
 
mpgxsvcd said:
The GH2 does not offer 1080p @ 30 FPS in any native form. I haven't heard even one complaint about that. I really wish the GH2's 1080i mode was like Sony's 1080i PSF @ 30 FPS mode. That is much more useful.
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That's because 30p isn't as essential for NTSC users as 25p is to PAL users. If the GH2 had no 24p there would be a masses of "whining"! Besides, the GH2 does at least have the option for 30p but at 1280x720, whereas it has NO option for 25p AT ALL.


Though, I was just wondering whether there's some sort of 'smooth motion on/off' option somewhere in the menu. Philip Bloom didn't seem to complain about any lack of 25p when he used it, but mentioned that it was still the 17mbps mode... Maybe the GH2 does support 25p & 30p after all, but in interlaced containers. Time will tell... but in the meantime I'm going to keep on "whining" about 25p just in case Panasonic is listening...
 
Calculations for 2.6x Crop Mode + F-Number = 5.2x less shallow DOF

Calculations for 2.6x Crop Mode + F-Number = 5.2x less shallow DOF

Calculations for 2.6x Crop Mode + F-Number = 5.2x less shallow DOF

I'd like to change the discussion, if only temporarily.

Just want to share what I've calculated regarding the 2.6x crop mode and its implications for the equivalent Depth of Field. Before I start, lets be clear that cropping only effects DOF properties not low light ability of the F-Number (i.e. the image never gets darker, just less shallow).

I've calculated this carefully, both the quick way (2 x 2.6 = 5.2) and the long way.

On a Full Frame 35mm format sensor (e.g. Canon 5D)
A 6mm F1.4 C-mount (1/2 inch format) will "look" like a 6mm F1.4 lens with severe pin hole vignetting on 35mm format.

On a m4/3 sensor (default 2x crop factor, e.g. GH1) but ALSO using the 2.6x Crop Mode (1:1 pixels)
A 6mm F1.4 C-mount (1/2 inch format) will "look" like a 31.2mm F7.3 lens (but with the low light abilities of an F1.4 lens) on 35mm format.

Reason:
FOV = (Crop Factor A x Focal Length) x Crop Factor B = (2 x 6) x 2.6 = 31.2

OR

Analyzing Diagonal Image circle sizes
m4/3 sensor = 21.6mm diagonal image circle
1/2 inch sensor = 12.7mm diagonal image circle
m4/3 sensor with additional 2.6x crop = 8.3mm diagonal image circle (21.6/2.6=8.3)
35mm full frame = 43.3mm diagonal image circle

43.3mm/8.3mm = 5.2x crop factor!

F1.4 Depth of Field x 5.2 crop factor = F 7.3


Resources on DOF and Crop Factor
See page 10 of:
http://www.zeiss.com/C12567A8003B8B6F/EmbedTitelIntern/CLN_35_Bokeh_EN/$File/CLN35_Bokeh_en.pdf

crop factors vs dof.jpg


Note: this assumes the 2.6x crop mode refers to extending the 2x sensor crop factor by an additional 2.6x not just 0.6x.
 
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Ouch. My God.
Is it possible to move discussion about DOF, FOV, and sensor diagonals to other thread?
I am just becoming sick reading this again and again.
Sorry.
 
At least I'm discussing what the GH2 can do rather than what it CANNOT (i.e. 25p framerate). If you must move my post, at least name the thread something like "Discussing actual 5.2x crop factor of 2.6x crop mode". My brain is fried after 1 hour of writing.
 
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In the end, Panny will add 25p to the firmware, not because anything said here, but as a feature, when reviews start coming in comparing all the competitors features. From Bloom, the GH-2 he was given was really unusable. He had to return it and is waiting for a new one to test, either in London, or when they send him to Osaka Japan shortly. That tells me the wonderful Panasonic engineers have their hands full. With the first retail batch to be sold in Japan this week, I cross my fingers for them, they got all the bugs worked out. I hope its just firmware to be fixed, and not hardware issues. I'm going to get a GH-2 when they are more readily available. But for now I think I will wait for the smoke to clear.

Also, remember the poor engineers also have to get the AF-100 done in less than a month. Bloom's recent test reported that atleast the software was only 75% complete.

So, I'm pretty sure there will be firmware updated by December.
 
Christ, who would have thought my little post about the lack of a major (main?) broadcast aquisition standard on the pre-production GH2s would have triggered such a debate. I suppose being BBC centred you really only have 2 framerates to choose from 1080i50 or 1080p25 so thats why I would harp on about the lack of decent support for these 2 formats on the GH2.

However maybe the final production GH2s will offer proper bitrate support for the majority of its userbase around the globe and not just become centered on New York & Tokyo.

PEACE AND LOVE.
 
RieniO said:
...if the majority of messages is negative and people with a positive attitude stop reading because they're getting fed-up?
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I haven't heard anything from you but negativity so far. How about focusing on the topic of the thread rather than abusing other posters with juvenile insults?
 
Picturequest said:
In the end, Panny will add 25p to the firmware, not because anything said here, but as a feature, when reviews start coming in comparing all the competitors features. From Bloom, the GH-2 he was given was really unusable. He had to return it and is waiting for a new one to test, either in London, or when they send him to Osaka Japan shortly. That tells me the wonderful Panasonic engineers have their hands full. With the first retail batch to be sold in Japan this week, I cross my fingers for them, they got all the bugs worked out. I hope its just firmware to be fixed, and not hardware issues. I'm going to get a GH-2 when they are more readily available. But for now I think I will wait for the smoke to clear.

Also, remember the poor engineers also have to get the AF-100 done in less than a month. Bloom's recent test reported that atleast the software was only 75% complete.

So, I'm pretty sure there will be firmware updated by December.
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I agree with this. They didn't give a GH2 to Bloom for nothing, and they will listen to him.
 
DanDOF said:
Just want to share what I've calculated regarding the 2.6x crop mode and its implications for the equivalent Depth of Field. Before I start, lets be clear that cropping only effects DOF properties not low light ability of the F-Number (i.e. the image never gets darker, just less shallow).
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With a 2.6x crop, fewer total photons are being collected by the reduced number of image sensing cells. Since the same level of luminance is maintained, does the effective noise level increase?
 
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