HPX2700 or PMW350?

[David Heath]

Originally Posted by Jeff Regan

It is worth remembering that in the U.S., ABC, ESPN, ESPN2, and all Fox Networks are 720/60P. I've had to submit D5 and SR tapes in 720/60P to Fox.

There's a significant number of stations in Europe that are also currently 720p/50 (though in a minority). It makes sense (at the moment) for one which is fundamentally all sport or similar live action, much less so when a mixture of programming (especially films and drama) are shown, since 1080i/25 also allows 1080p/25 transmission via psf. The EBU also recommend 720p/50 as the current preferred format for transmission.

So why do they then advocate 1920x1080 chips and codecs as preferred for acquisition? It may be quite a while before we see 1080p/50 transmission, though it's the ultimate goal, but in the meantime there are strong moves towards 1080p/50 ACQUISITION. Partly to get the infrastructure in place for when 1080p/50 transmission is feasible, partly for best quality archiving, but mainly because it seamlessly converts to either 720p/50 or 1080i/25. If that becomes the inter-broadcaster standard, no stations will feel disadvantaged by their chosen transmission standard

In the meantime, 1920x1080 chips are optimum for 1080p/25 production, and downconvert well to 720p. Whereas 720p upconversion can't make good resolution that was never there.

They were more than a bit surprised when this six figure investment in cameras would not allow them to shoot 720 or any progressive frame rates over 30 fps. Apparently they hadn't read the brochure before purchasing.

A good story! Shows a pretty fundamental lack of research on behalf of the buyers, but also begs the question why the 3700 has no 720p/60 recording mode? So take full advantage of the chip resolution when in 1080p or 1080i/30 mode, yet still offer 720p/60 and the varispeed capabilities of the 2700 when desired.

[Alister Chapman]

Well Panasonic fooled me too. I read all the talk of the 3700 being a Varicam so assumed it had the full range of Varicam features, especially as it is a much more expensive camera. I had assumed (incorrectly) that it would due 60P, albeit at 720P. I'm quite shocked that it doesn't. Certainly makes the NHU's choice a lot narrower.

No the 350 doesn't ramp while shooting.

[Jeff Regan]

Alister,

That's right, the Varicam name should imply variable frame rates up to 60 fps, this is why I thought it didn't make sense from a feature set or marketing strategy to call the 3700 a Varicam. I had been saying this for months. The Varicamp co-instructor said the same thing and felt that "HPX3700 RGB", due to its 4:4:4 dual link output ability, was a better name.

How many HD SDI outputs does the 350 have? Specs show only one, is that correct? I really like having three HD SDI outputs on the 2700 so I don't have to get into looping or DA's for monitoring.

Jeff Regan
Shooting Star Video
Shooting Star Video

[Matt Gottshalk]

Originally Posted by Alister Chapman

\



Seeing as you can't tell the difference between 720 and 1080 that's understandable. Im sure there are many that would disagree. Including the EBU, BBC, Nat Geo, Discovery etc who all now want 1920x1080.

Not true on NatGeo, they are still 720P.

[Jeff Regan]

Yes, Nat Geo is a Fox channel, all of which are 720P.

Jeff Regan
Shooting Star Video
Shooting Star Video

[Steve Phillipps]

And presumably they're not inundated with viewers writing in to complain about their picture quality!
I think that may be the key, at a certain point something is just "good enough" meaning that if you increase the quality you can measure the difference and post specs and side by side comparisons but in it's final form there is no difference. It's very much the same with stills, the difference in image quality from a £300 consumer DSLR and a £5000 pro one is not really significant on the web, in magazines, in 10x8 prints. It's only when you do massive enlargements that it shows. Ditto with moving picture I guess, you'll notice some difference on the big screen - they did when turning Planet Earth into Earth for cinema release, the producers' first criticism of Varicam, that it didn't hold up so well as the 1080 cams. The biggest problem though AFAIK when making Earth was stabilising shots as the long lens work showed lots of wobble when maginified - hence from then on we've all been urged to get bigger tripods (Ronford Atlas, O'Connor 2060 etc.)!
Steve

[Simon Wyndham]

Steve, the push is not just for 1080, but for 1080p at 50 or 60fps. Such a standard would make things easy because as David pointed out it can be downconverted very well to 720p/50/60 as well as 1080p/25/30 very easily.

Sony have already gone some way towards this with chips that support this. I believe SR can handle these framerates already, and most new TV's with HDMI can also display it already. Sanyo have already kickstarted it at a consumer level with their new Xacti cameras. All that is needed is for more professional cameras to start supporting it. Using LongGOP compression as per digital broadcasting the datarate does not need to be hugely higher than it is already either.

But also the other thing you missed is that although broadcasters might be showing 720p now, many of them want to be secure for the future. 1080p at higher framerates would mean that there wouldn't be the current spaghetti mess of which HD format to shoot in any more. Regarding the wildlife, with the rarity of many of the things being filmed it would certainly make sense to use a camera that would be capable of 1080p/50/60 as soon as possible.

[Steve Phillipps]

I'm sure you're right Simon that 1080 is the goal, but I think you missed my point re image quality - at some point good enough is good enough. I don't know anyone who's complained about the quality of Planet Earth for instance either on HD broadcast or BluRay. For TVs even upto 50" while there's no harm in having it 1080 there's probably no desperate need from a viewer perspective.
You raise an interesting point re 1080/50 or 60P. If a programme is transmitted at 50P that'll mean that for even half speed slomo in camera of course we'll need a 1080/120P camera. We'll all have to get Phantoms!
Steve

[David Heath]

Originally Posted by Steve Phillipps

I think you missed my point re image quality - at some point good enough is good enough

In principle you're absolutely right. But what's good enough on a 19" screen is not good enough on a 100" screen, given the same viewing distances!

OK, that's a bit flippant, but a lot of work was done a few years ago to try to discover exactly what "good enough" was. The conclusion was in favour of 720p - but unfortunately the research became out of date almost before it was published. Not through any fault of the researchers, but because screen technology and sizes improved way faster than anybody thought.

For UK homes, the average viewing distance is about 2.7m, and that's remained pretty constant for a long time. The research was assuming about 37" as the "norm" screen size for the foreseeable future, and at the time the best resolution on domestic screens was typically about 1350x768. That's nowhere near true anymore, as a trip to any High Street proves. I've got a 1920x1080 42" Panasonic, but 46" and even 50" are quite common now, and it's hard not to get 1920x1080. The same research indicated that 720p wasn't "good enough" for a very significant percentage of viewers for those screen sizes.

Hence the drive to 1920x1080. True, the full advantage may not be seen on all screens, but that's no argument for not trying as hard as is practical, certainly for top end production. Neither 720p nor 1080i are seen as totally satisfactory for transmission, but they are currently the best that's realistically practical. Transmission to home of 1080p may still be a way off, but that's no excuse for not producing as such unless there are overriding factors - and the importance of varispeed for wildlife filming is a good example of that at the moment.

[David Heath]

Originally Posted by Simon Wyndham

Regarding the wildlife, with the rarity of many of the things being filmed it would certainly make sense to use a camera that would be capable of 1080p/50/60 as soon as possible.

Only for slow motion - the whole point of 720p in this context is it assumes 720p/25 as the viewing format, for overcranking to give slow motion. If you're transmitting 720p/50, such as the 2700 won't give slow motion.

Which is why what's really needed is a camera with 1920x1080 chips, able to give 1080p/25 recording for normal speed shooting, but be switchable to 720p/25 when overcranking is needed. Accept the resolution drop just for off-speed work. It's really not surprising that the people Jeff earlier referred to got caught out by assuming the 3700 did just that. Why the 720 mode was missed off it is totally beyond me.

[Simon Wyndham]

If you're transmitting 720p/50, such as the 2700 won't give slow motion.

That's true. Which is why we need 1080@120 :-)

Which is why what's really needed is a camera with 1920x1080 chips, able to give 1080p/25 recording for normal speed shooting, but be switchable to 720p/25 when overcranking is needed. Accept the resolution drop just for off-speed work.

The trouble with that is that it is a pain to do. The EX can do this, but I hate having to switch resolution modes. It means going into a menu, which takes time, and sometimes the event I want to capture goes by. So if I know I might need to do off speed shooting a fair bit I will just shoot 720p. That way I can just press a button on the side, dial in my framerate and press record. Or if my framerate is set I just press the button followed by record.

So it would be better to have a 1080/60 capable camera. There's nothing stopping the main recording being 25p while the offspeed is up to 60. Just as now you shoot 720/25 with 60fps overcrank instead of just using 720/60.

Though really I would argue that shooting at 25p so that slow motion can be seen is sort of a fake effect. 25p is such a slow framerate that surely a camera that shoots 120fps for slow mo and 50 or 60p as normal is far more desirable? Decent slow motion in 50 or 60p playback. Ultra slow motion for 25p shoots.

[Jeff Regan]

Well, we know there are large sensor RAW cameras that can shoot higher frame rates, although many producers don't know that the RED One shrinks the sensor size the higher the frame rate selected, losing resolution.

The HPX3700 consumes 38 watts, 10 watts more than the 2700 due to the full raster CCD's. The Sony SRW9000 consumes 57 watts in power save mode without any option cards. Hopefully this will go down once the large sensor CMOS option and SSD recording options appear in 2011 or so.

1080/60P with CCD's is expensive and power hungry, wasn't practical for Panasonic to do with the 3700. Certainly the P2 cards have the throughput to deal with bit rates in the 600Mbps range. Why they couldn't provide 720P at any frame rate for the 3700 or 3000, I don't understand.

I love the convenience and frame rate flexibility that shooting in 720P provides. With my 2700, I can choose two different frame rates on user buttons. I can ramp from any frame rate to any other within 1-60 fps while recording and back, if I want. Not to mention being able to record 160 minutes on a single 64Gb P2 card in 720/24PN vs. 80 minutes in 1080/24PN.

My screening room has me seated 10' from a 100" screen. I can tell the difference between 480P and 576P compared to 720P, but I cannot see the difference between 720P and 1080/60i. Indeed, on the high end projector forums, the projector enthusiasts, who are actually pretty critical in their viewing, can't tell the difference between 720P and 1080P projectors with 120" screens or smaller. I can tell looking at pixel structure in white titles, but not on normal live action at normal viewing distances.

Jeff Regan
Shooting Star Video
Shooting Star Video

[Steve Phillipps]

Jeff, I know that BBC did viewings when Varicam first came out, on projectors and big monitors and looked at pictures from both Sony F900/750 and Varicam and many decided subjectively that the Varicam just looked better. Perhaps not due to sharpness alone, as has been said it has a very nice quality to the image apart from sharpness.
Simon, I actually don't find it too bad changing mode on the EX3, it was the PDW700 where it was a nightmare - 2 problems over the way it's done on the EX3, first you have to power down for the change to take effect, second you have to change the bloody dsc as they won't do 1080 and 720 on the same one!
1080/60 (let alone 1080/120) does seem to be a struggle for CCD cameras, and with CMOS you've always got skew issues, and if you're after slomo the chances are your subject is moving fast and hence likely to induce skew. It really does seem like a good solution is a pretty long way off - but you never know with the way technology advances. I've never seen skew when shooting with the Phantom HD, but perhaps it becomes less and less evident when shooting really high frame rates?
Steve

[Simon Wyndham]

I've never seen skew when shooting with the Phantom HD, but perhaps it becomes less and less evident when shooting really high frame rates?

Depends what kind of CMOS sensor they use. Skew isn't necessarily something that happens on CMOS regardless. CMOS chips can be made with zero skew, but is expensive and difficult, and I believe also reduces the effective light gathering area due to more jiggery pokery having to be crammed onto it. Someone else other than I will know the specific reasons.

The Phantom may not be showing skew due to the sheer speed of it. At 500-140,000fps that sensor is going to have to be clearing at a phenomenal rate.

[Steve Phillipps]

I think it's not actually CMOS as such it's whether it has a global or rolling shutter. Global shutters of course have no skew, but that's the bit that's expensive I believe.
Pretty sure the Phantom has a rolling shutter actually, as does the RED of course. There is another highspeed camera called the Weisscam which I believe has a global shutter.
Steve