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Author Topic: GH3 Review - Video  (Read 5743 times)
Sareesh Sudhakaran
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« on: October 25, 2012, 10:44:06 PM »
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Here's a line from the new GH3 Review:

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A number of broadcasters regard a data rate of 50 Mbps as the minimum acceptable for on-air use from outside sources of programming. The BBC is a prime example of this. The Panasonic GH3 is capable of 50 Mbps at 1080/60p, but up to 72 Mbps at 1080/24p or 1080/30p.

Just to be clear, there are TWO requirements for codecs, by the EBU/BBC:

Interframe - 50 Mbps
Intraframe - 100 Mbps

In this case, the GH3 will be unacceptable for broadcast since its intraframe codec is less than 100 Mbps. A broadcast standard also requires 4:2:2 chroma sub-sampling, which might be available from the GH3 HDMI port. The maximum interframe codec is 28 Mbps, which is also less than the 50 Mbps requirement.

Panasonic will not shoot itself in the foot - their stake in broadcast technology is on par with Sony, JVC and Canon.

And I will be very surprised if there is any visible difference between the 72Mbps I-frame and the 28Mbps AVCHD.
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« Reply #1 on: October 26, 2012, 11:38:19 AM »
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What "new GH3 review"?
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David S
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« Reply #2 on: October 26, 2012, 03:40:30 PM »
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See  "what's New" for Mike's initial comments on the GH3.

Dave S

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tho_mas
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« Reply #3 on: October 26, 2012, 04:41:45 PM »
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Michael,

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Also unusually for anything but a dedicated video camcorder the GH3 can record Time Code; free run, rec run, count up, and also drop frame. If you don't know what these are, you likely don't need them, but for people working in multi-camera environments this can be a big deal.

Here's a quote of the Senior Product Manager (Germany)
Quote
Sync to studio code is not possible at that stage. Only record run and free run.
(see here: http://www.personal-view.com/photokina/coverage/interview )

As far as I can tell from product photos the GH3 also doesn't seem to have a TC connector.

So... are you assuming the GH3 can be synced in a multi camera setup or did you actually synced it to external TC?

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tjbates
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« Reply #4 on: October 26, 2012, 05:23:39 PM »
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I really appreciate Michael Reichmann's preliminary GH3 field report. Cameras are coming out thick and fast - it must be hard to keep up.
The fact that he has decided to pre-order for his video production needs means that this camera must be up to spec. However, I agree that the magic 50Mbps is not enough for HD acquisition for many broadcasters without 4.2.2 chroma sub sampling. That said, I'm glad Panasonic have decided give the user the choice of so many codec wrappers and higher bit rates.
I'm still concerned that the GH3 will suffer from moire and aliasing. The web is buzzing with discussions about the GH3's poor performance in this regard.
The truth is - that we simply can't make judgements on the quality of the stills and video output until we get a final firmware version into the hands of someone who knows how to look for and test these things.
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« Reply #5 on: October 26, 2012, 06:20:06 PM »
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See  "what's New" for Mike's initial comments on the GH3.

Dave S



Well, I'll respond with the same comment I made to someone else earlier today.  For those of us, and I'm sure I'm not the only one, who don't pore over every detail what's posted on the LuLa site, providing a link to the relevant material would be helpful.

WRT the 'specifications' of The Beeb or any other broadcaster, I'll say the same thing I said in previous threads with similar discussions.  These 'specifications' are a moving target.  When major studio productions are being made on an increasingly regular basis with video capable DSLRs that allegedly don't meet spec, it tells you all you need to know about the 'specifications'.

As far as 'the web is buzzing' about moiré and aliasing with the GH3, it's difficult to understand how the 'buzz' is being generated when there are no actual cameras available for people to test.  Michael appears to have got one but he's one of the few.  I'll also point to something I've noted previously and that's that Bloom shot with a pre-production version and he thought it was pretty damned good.  I'll take the view of someone like Bloom who's actually shot with one and has a clue what he's talking about over 'internet buzz' any day, and twice on Sunday.
« Last Edit: October 26, 2012, 06:25:32 PM by BobFisher » Logged
Morgan_Moore
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« Reply #6 on: October 26, 2012, 11:08:00 PM »
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it tells you all you need to know about the 'specifications'.

Your commissioner tells you all you need to know about specs.. even if they are irrelevant, outdated, wrong etc.

Ive had a bunch of 'use the 5d' (not from the Beeb but from 'cool' indies) when I actually own 3 better cameras

S
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tjbates
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« Reply #7 on: October 27, 2012, 02:47:25 AM »
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I agree that philipbloom.net is a very good source of informed opinion on video cameras but I would also take his advice and never just take his word for it - actually go down to your local camea shop and test it out for yourself.
This is what he said about the GH3-
"I can’t review the camera as such for now..that will have to wait until a release camera or close to release camera is available but going from what I have seen and used so far it’s a massive step up from the GH2 in build quality, feel, image, low light. All important stuff."

Testing out the GH3 is not a reality for almost all of us. In fact testing it at all before final firmware is complicated. Michael wrote a caveat in his prelim. field review.

For those who have had an opportunity albeit limited time with the GH3 - no one has shot anything purposefully in order to test aliasing or moire.
This isn't to say there aren't examples of this. Here's one-
http://vimeo.com/groups/gh3users/videos/49864350
The table legs are buzzing with aliasing artifacts.

I agree the net is not "buzzing" with interest about the GH3 moire and aliasing - (I got carried away a bit.)
But for those who have interest in these things - there is a concern that Panasonic may have missed the mark in this regard.
Personal View is the site of the GH2 hackers.
http://www.personal-view.com/talks/discussion/4733/official-panasonic-gh3-topic-series-2
http://vimeo.com/groups/gh3users

Why is aliasing and moire a problem at all? The GH2 and 5DMK3 are the only DSLR type cameras that do not display easily noticable aliasing and moire
in video mode. BBC cameraman Johnnie Behiri found that the Sony A99 has a distracting level of aliasing and moire.
https://vimeo.com/50980422
Many wish to have a camera with the GH3's specs that is clean from distracting levels of artifacting. I have used the GH2 with success for broadcast work standard definition assignments. The GH2 and GH3 shoot 50i and 25p. which is a requirement for PAL transmission.
https://vimeo.com/43783066

If the GH3's final release version is free of annoying artifacting, then at least we have another choice beyond the GH2 and 5DMK3.


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RFPhotography
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« Reply #8 on: October 27, 2012, 06:23:15 AM »
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That's not my point, Morgan.  My point was that the commissioners break their own rules when it suits them.  The result being that the specifications are, essentially, meaningless and are casually enforced at whim. 

TJBates, I wasn't suggesting that Bloom's opinion should be taken as the final word nor that potential buyers shouldn't check the camera out for themselves before buying.  I was merely suggesting that he's a pretty reputable source of information who shot a pretty serious project with a pre-production model, and while it wasn't a full out test, he was impressed with what he got from the camera.  The chair legs are pretty bad in that clip.  Yet in this one, there appears to be no sign of aliasing.  I might have expected to see it in the angled lines of the ladder.  Your original statement was correct.  Waiting till there are full production models available to test is the right approach.  And that's what I was trying to get at earlier as well.
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michael
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« Reply #9 on: October 27, 2012, 09:57:58 AM »
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Just as an aside, to my knowledge (via Panasonic) all the early reviewers as of last week were shooting with V0.5 firmware. Most, myself and Phil Bloom admitted this, and pointed out that a number of features were incomplete or missing. It just isn't possible with 0.5 to make any definitive judgements on how the camera will perform, and anyone that claims otherwise is being disingenuous.

Sadly, there have even been a couple of so-called reviews appear in the past few days that claim to have tested all the features and pass judgements. If so they're doing better than the engineers in Japan who were just given an extra two weeks to get things finished up properly. But then, it's never been hard to write a review based a a spec sheet and 30 minutes handling a body at a trade show.

Michael
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tjbates
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« Reply #10 on: November 06, 2012, 12:18:33 PM »
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Maybe this edges us closer to the truth?

http://www.eoshd.com/content/9170/panasonic-gh3-real-world-test-pre-production-firmware

The take away - The GH3 may resolve detail slightly better than the GH2 in stills and video w/out hack but at the expense of more aliasing and moire.

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michael
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« Reply #11 on: November 06, 2012, 12:27:22 PM »
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I read that write-up last night and thought it was well done. He missed a few things, like flashing highlights out of the HDMI – so not totally clean if these are left on), but otherwise did a great job.

Just remember, this is still firmware V0.5c. There's a long way to go till we really know what video quality from a production camera will be like. I just think that it's premature to pass judgement at this point.

Michael
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tjbates
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« Reply #12 on: November 06, 2012, 03:47:23 PM »
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Agreed. However, I'm not preordering as I'm unsure if a firmware update can eliminate even the smallest degree of aliasing and moire. I'm also unsure if it's really a problem at all.

What's also unclear is if noise and banding in ETC has been improved especially when slightly underexposing. I'll test it at my local camera store when it comes in and make a decision based on that.

The GH2 right now looks like a fluke. It arguably has the best resolution video in a DSLR style camera w/out hack under $6K, with very low levels of moire and aliasing. Clearly the GH3 shows some improvement in other areas over the GH2 - headphone jack, nicer colour palette, dynamic range?, audio monitoring, weather sealing and better quality stills?

Hopefully, the best case scenario is that moire and aliasing isn't too bad.
Worst case is that we have a similar 5DMK3 situation where one aspect of the camera has been improved (aliasing and moire) while another aspect has has not been improved (resolution).

As they say- (whoever they are)
One thing's for certain.....only time will tell.
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Richard Pickett
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« Reply #13 on: January 03, 2013, 07:14:08 AM »
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Here's a line from the new GH3 Review:

Just to be clear, there are TWO requirements for codecs, by the EBU/BBC:

Interframe - 50 Mbps
Intraframe - 100 Mbps

In this case, the GH3 will be unacceptable for broadcast since its intraframe codec is less than 100 Mbps. A broadcast standard also requires 4:2:2 chroma sub-sampling, which might be available from the GH3 HDMI port. The maximum interframe codec is 28 Mbps, which is also less than the 50 Mbps requirement.

Panasonic will not shoot itself in the foot - their stake in broadcast technology is on par with Sony, JVC and Canon.

And I will be very surprised if there is any visible difference between the 72Mbps I-frame and the 28Mbps AVCHD.

As I read the BBC's requirements document, it is not the camera but the footage which should meet the minimum standards. This includes not just bitrate but things such as the absence of moire and aliasing and other visual artifacts. I don't see why the GH3, shot at 50 mbps interframe, should not meet these standards, provided that no intraframe footage is included. The fact that the camera only shoots up to 72 mbps in intraframe should not be relevant if i-frame is not used.
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Sareesh Sudhakaran
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« Reply #14 on: January 03, 2013, 08:29:49 AM »
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The EBU has a camera grading system detailed on their website. They have begun to look favorably at DSLRs, but still don't consider most of them as broadcast worthy. Luckily, they document everything on their website.

Sometimes they contradict themselves. The safest methodology is to refer to their previous DSLR tests, results and observations. But nobody can speak on their behalf, and they don't articulate their knowledge very well, for fear of offending 'somebody'. Furthermore, their recommendations are mainly to their members, who are free to do as they please.

By the way, does the GH3 shoot 50 Mbps interframe? I thought it was 28 Mbps?
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« Reply #15 on: January 03, 2013, 10:05:18 AM »
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According to the spec sheet, it can do 50 mbps inter, http://panasonic.net/avc/lumix/systemcamera/gms/gh3/specifications.html.
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Sareesh Sudhakaran
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« Reply #16 on: January 03, 2013, 09:07:05 PM »
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Thanks, Bob. You're right. I wrote a blog post about it a couple of weeks ago, and I've forgotten my own analysis!
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