Convergent Design Nano Flash & Z7 ?

[Greg Laves]

Originally Posted by Greg Laves

Again, I will stress that this is by no means any valid method of comparison. But I do think the HDMI output from the Z7 will compare very favorably with the EX-1/EX-3. Both are 1920 x 1080 with 4-2-2 color output through the HDMI port. But you would have to think that the 1/2" full raster chips will have an advantage over 1/3" chips using pixel shifting technology. DOF control would be one obvious area, of course.

David, I readily acknowledged that this was not a valid comparison. But I still feel that the HDMI output from both cameras will be pretty similar. I am not an engineer but from the Sony propaganda I have read, it is my understanding that both cameras are "full HD" through the HDMI port. It is not HDV out of the HDMI port on the Z7 and HD from the EX-1. David, I am curious if you have actually compared the outputs from both cameras directly?

As for the cost comparison, any Z7 owner would loose a considerable amount of money by selling the Z7 he already owns and buying a new EX-1 or EX-3. The dollars do not compare. Which gets back to the original question of "Is this (NanoFlash) going to be something we could use on the Z7?" From what I have read and what I know, it seems like it would definitely be something to consider.

[David Heath]

Originally Posted by Greg Laves

But I still feel that the HDMI output from both cameras will be pretty similar. I am not an engineer but from the Sony propaganda I have read, it is my understanding that both cameras are "full HD" through the HDMI port. It is not HDV out of the HDMI port on the Z7 and HD from the EX-1.

Firstly, I don't think the EX has an HDMI output - it's HD-SDI - but OK, that's a bit irrelevant here. It's quite true that the HDMI output of the Z7 will bypass the HDV compression, so yes, that's a good benefit for using a nanoFlash to improve what a Z7 gives you. But whilst you may get a full HD signal through HDMI (in respect that it's 1920x1080 per frame) it won't be - can't be - 1920x1080 resolution. To get that level of resolution you need 3 2 megapixel chips (which the EX has), whereas the Z7 only has 1 megapixel chips.

The actual layout is complex, best described as two 960x540 diamond arrays interleaved. (Think black/white tiles on a bathroom floor!!) It's clever - effectively giving equal horizontal/vertical resolution, effectively equivalent to about 1440x810 from a conventional sensor. But it's not 1920x1080, even if carried in a 1920x1080 signal. Anymore than 16mm blown up to 35mm film can give the true resolution of native 35mm film. It's uprezzing to get the "full HD", and that's not the same as getting it natively.

It should also be obvious that any resolution difference will only be really obvious on a high res monitor, but nowadays there are a great many 1920x1080 panels about.

David, I am curious if you have actually compared the outputs from both cameras directly?.

I've not personally compared the two cameras side by side, though have used the EX quite a lot. But I have seen zone plate and other test results, done very scientifically (to a far higher standard than any test I could do) - and they pretty well confirm what the theory predicts. As example, see the results of the tests done by the BBC R&D labs on the EX cameras - http://downloads.bbc.co.uk/rd/pubs/w...X1-and-EX3.pdf . (Look at the zone plates towards the end.)

As for the cost comparison, any Z7 owner would loose a considerable amount of money by selling the Z7 he already owns and buying a new EX-1 or EX-3. The dollars do not compare.

I disagree. To add a nanoFlash to a Z7 will cost about $3,000. If you traded a Z7 in for an EX, I doubt you'd have to pay as much as $3,000 in difference - trading in for an EX is a cheaper option than adding a nanoFlash.

I'd still argue that it's also a better option for quality than the Z7/nanoFlash *if the primary interest is HD*. If you do a lot of SD native work, especially with a tape workflow, the Z7 obviously makes a lot of sense.

[Steve Phillipps]

Originally Posted by David Heath

I disagree. To add a nanoFlash to a Z7 will cost about $3,000. If you traded a Z7 in for an EX, I doubt you'd have to pay as much as $3,000 in difference - trading in for an EX is a cheaper option than adding a nanoFlash.
.

Always value your learned opinion David, some good points. But I kind of assumed Greg was meaning that it'd be cheaper to get a Nanoflash on the Z7 than a Nanoflash on an EX3, I thought this was what we we talking about. The basic idea is that the compression systems on both cameras are not great and that the Nano is the way to go, just a question of how much difference the camera heads are making.

One more important note I'd say, especially for wildlife shooters is the EX ability to do slomo, and with that in mind I'd be interested in how the new JVC 700 performs, as it'll do slomo and with CCDs so no rolling shutter problems.
I thnik we also have to be carfeul about placing too much emphasis on the numbers and even on things like zone plates. This discussion has happened here before, comparing say the Varicam HPX2700 to an EX camera or even the Z7 and you've got more pixels in the latter two but would you then expect it to have a better picture than the Varicam? I wouldn't have thought so.
Steve

[David Heath]

Originally Posted by Steve Phillipps

But I kind of assumed Greg was meaning that it'd be cheaper to get a Nanoflash on the Z7 than a Nanoflash on an EX3, I thought this was what we we talking about.

If that's what he meant, then I misunderstood, but that's not what I've been referring to. My point was that if you've got a Z7 and $3,000 burning a hole in your pocket, that money *MAY* be better spent against an upgrade to an EX than adding a nanoFlash to the Z7. I strongly feel that it's at least worth considering. So the comparison is a basic EX versus a Z7/nanoFlash combination.

The basic idea is that the compression systems on both cameras are not great and that the Nano is the way to go, just a question of how much difference the camera heads are making.

I'd say the 35Mbs codec is a big leap up on HDV, the steps up to the higher codecs much less significant proportionally. Adding a nanoFlash to a Z7 will certainly improve the codec situation, but do nothing about the front end. Upgrading it to an EX will improve the codec situation significantly (to 35Mbs), AND give a superior front end. The question is whether the front end difference is more significant than the difference between 35Mbs and the nanoFlash codecs. My suspicion is that the answer is "yes".

I thnik we also have to be carfeul about placing too much emphasis on the numbers and even on things like zone plates.

In principle, I agree. I've long felt that numbers can fairly accurately predict a "ceiling" performance, above which you can be pretty sure a camera just won't (can't) perform. What they won't do is predict how close to that ceiling they will get in practice. (Expensive ones are likely to get a lot closer than cheap ones!)

But here we are comparing two Sony cameras with very, very similar technologies in their front ends, even with pixels of the same individual size. The big difference is that the EX chips have twice the area (1/2" v 1/3"), so twice the pixel count. It's also worth noting that the EX is higher up the Sony tree than the Z7, so all in all it'd be very surprising if it didn't outperform the Z7. The question is by how much, and whether it's far more significant than 35Mbs v 50/100Mbs codec differences. My guess is that it will be, but obviously the only real test is for someone with an EX, a Z7, and a nanoFlash to do the test.

[Steve Phillipps]

All fair points.
About the codec though, presumably due to the EX's greater amount of real pixels (ie twice as many) and the fact that it has twice the data rate, does that not mean they have the same (or similar) compression? I suspect the answer is no, but maybe it's closer than the numbers suggest?
And I think the key is definitely what you said, that the EX front end image is likely to be better, but by how much - I suspect not enough to be a big deal even a big HD TV. Could be wrong though!
Steve

[David Heath]

Originally Posted by Steve Phillipps

About the codec though, presumably due to the EX's greater amount of real pixels (ie twice as many) and the fact that it has twice the data rate, does that not mean they have the same (or similar) compression?

The EX has twice as many imaging pixels on the chips as the Z7, but after processing the number of recorded pixels per frame is only 33% higher than the Z7 (1920x1080 v 1440x1080) for luminance. Equally, the EX data rate is 35Mbs v 25Mbs for HDV, so an increase of 40%.

In practice these numbers don't tell the whole story, the benefits are greater than simple percentages predict, a lot being down to being able to make use of more redundancy within a higher definition image. Same principle as why an HD picture with 5x the number of pixels per frame as an SD image doesn't require as much as 5x the bandwidth for transmission, assuming the same basic codecs etc. Similarly why 1080p/50 wouldn't require twice the transmission bandwidth of 1080p/25 - even though it's twice the original data.

Yes, the 50Mbs codec will be better still (it's 4:2:2 for one thing), but I don't think the difference between 35Mbs and 50Mbs will be as pronounced as between HDV and 35Mbs.

[Greg Laves]

David, while it is true that the EX-1 "records" 1920 x 1080 and the Z7 "records" 1440 x 1080 (BTW, just like the high end XDCAM's), the actual output of both (HD-SDI port, EX-1 and HDMI port, Z7) is exactly the same, 1920 x 1080. Surely, you are not thinking that anyone would record video in the camera first and then put it out to the NanoFlash later. The resolution that each camera "records" internally is not an issue at all here. And from what I understand the difference in data rate has to do with how many frames are included in each long GOP segment when the data is recorded. It has no bearing on the HDMI or HD-SDI output. The internal compression would be completely bypassed if you are recording into an external device at a higher data rate, so it has no bearing on this discussion that I can see.

[Steve Phillipps]

Sorry Greg, we've made a slight deviation from the thread in talking about ex vs z7 codecs! David's points from what I understand do seem correct.
Steve

[David Heath]

Originally Posted by Greg Laves

The resolution that each camera "records" internally is not an issue at all here. And from what I understand the difference in data rate has to do with how many frames are included in each long GOP segment when the data is recorded. It has no bearing on the HD MI or HD-SDI output.

As Steve implies, the comments I made in post #21 were in direct response to Steve's questions in post #20, (hence the quotation box) so yes, how HDV is recorded is not an issue for most of the thread.

I haven't got the notes to hand, but I'm pretty sure that the GOP length doesn't vary between HDV/XDCAM-EX. It does vary between framerates IIRC (for both of them), 12 frames for 25fps systems, 15 for 30fps. (so half a second in each case).

Steve - I really can't emphasise too much just how many variables come in to play, and how much more there is than simple numbers indicate. In particular, that different coders can give widely different results with the same input, same bitrate, same codec. Hardly surprisingly, the more you pay, the better you get. In practical terms, I was very, very impressed with the EX codec.

[Steve Phillipps]

David, I don't know if you say the Convergent Designs tests, but their 100 mb/s showed a massive improvment over the EX codec, maybe enough to close the Z7/EX gap even. I don't use either camera so I can't say for sure, but I still get the feeling that to the eye on a big screen your viewer would be equally happy with the pics from either Z7 or EX when combined with the Flash recorders.
Steve

[David Heath]

Originally Posted by Steve Phillipps

David, I don't know if you say the Convergent Designs tests, but their 100 mb/s showed a massive improvment over the EX codec, ......

I've seen some tests - not sure if they're the ones you refer to. Fact is, the EX codec is pretty good in it's own right, to the extent that I haven't been able to see any artifacting at all on basic viewing, even stepping frame-frame through fast action. (Whereas I certainly could with HDV and AVC-HD.) I don't dispute the higher bitrate codecs will be better still, the 50Mbs version gives 4:2:2 for one thing, but I doubt I'll see glaring differences in straightforward viewing. (The benefits are more likely to come when codecs are cascaded or post work done.)

........maybe enough to close the Z7/EX gap even.

I just feel that's a gap you will be able to easily see with straightforward viewing, certainly on a 1920x1080 screen. But enough paper debating, it needs somebody to try it for real!

The other point which needs making is that it's not just about "quality". Using the extra money to fit a nanoFlash to a Z7 means another box to mount, more cables, worsening ergonomics etc etc. Using the money to trade a Z7 in for an EX means none of that.

[Greg Laves]

Originally Posted by David Heath

The other point which needs making is that it's not just about "quality". Using the extra money to fit a nanoFlash to a Z7 means another box to mount, more cables, worsening ergonomics etc etc. Using the money to trade a Z7 in for an EX means none of that.

To me the advantage of an EX1 over a Z7 has nothing to do with image quality. It has more to do with perhaps getting some jobs with the EX1 that you might not get with the Z7. Some producers are going to want that "higher end" camera because of technical snobbery, not because the image quality blows the Z7 into the weeds, because it simply does not blow the Z7 image into the weeds. Besides, I know of 2 EX1's I can rent if I really have to shoot with an EX1.

I have seen my footage on the biggest and best HD home entertainment systems that money can buy and it looks absolutely awesome. I have a partner that took an extended trip to Europe. The local high-end home entertainment retailer uses his footage every day to demo their big screens. He gave them some of his footage on Blu-ray and it easily looks as good as the demonstration footage that Sony and others supply to their retailers. They certainly would not be using it if didn't look terrific.

I had a V1 previously. I wanted an EX1 so bad I just couldn't stand it. But I wound up getting a deal I couldn't refuse on this Z7, instead. Since I have gotten the Z7, I have not been tempted once to get an EX1. Frankly, I just don't see it as a big enough step up. David, you seem to think it is a night and day difference but that leads me to believe that you have never actually seen any Z7 footage in a good HD environment. But I could be wrong about that.

What I want is to be able to keep my Z7 until something clearly better comes along that makes it really worth changing camcorders. But in the mean time I would like to be able to record my Z7's HDMI output in 1920 x 1080 and 4.2.2 color. Since that is what it puts out. And it would be nice to record in a higher bit rate to eleminate the HDV codec. It would be nice if it recorded on inexpensive CF cards. And having dual card slots would be nice. I hope something like that becomes available sometime soon. It doesn't seem to be too much to ask. Oh yeah. And it would be OK if I could use that external recorder on those rental EX1's also, if the occasion came up. It would also be nice if I could later move it to a newer, better camcorder somewhere down the line, if I want to. Right now, my partner in crime is looking at getting a BlackMagic stand alone box to hook up to a laptop so we can record 1920 x 1080, 4,2,2 color. It will be a much bulkier solution. But maybe we can get what we want by going down that path instead.

[Steve Phillipps]

Originally Posted by Greg Laves

What I want is to be able to keep my Z7 until something clearly better comes along that makes it really worth changing camcorders.

Greg, I think that's an interesting point, wanting to hang onto the Z7 until something a lot better comes along, and one of the strong points of the Nanoflash, the fact that if you bought one for the Z7 then changed camera the Nano would still be useful - you could even hook it up to a Sony F23!

Be careful when talking about seeing your footage on a big screen and thinking it looks great, if you're talking about the raw tape footage played straight from the camera or a deck, I know other people that have done the same and it does look great, but once it goes through the chain of editing then transmission to TV it hardly looks like the same footage. I have always assumed this is something to do with the codec and the reason why the 100 mb/s 422 type codecs are preferred for broadcast.
Steve

[Greg Laves]

Originally Posted by Steve Phillipps

Be careful when talking about seeing your footage on a big screen and thinking it looks great, if you're talking about the raw tape footage played straight from the camera or a deck,
Steve

Typically what I am viewing is footage that has been edited in Premier Pro and output to Blu-ray disc through Encoder. And then played back at the local high end retailer through various Blu-ray players, including Play Station 3. So it should be what an end user would see if they wanted HD material. We used to take them to Best Buy for playback testing but their manager finally said something about messing with their equipment, so we have made friends with a more exclusive retailer and all is good.

[David Heath]

Originally Posted by Greg Laves

David, you seem to think it is a night and day difference but that leads me to believe that you have never actually seen any Z7 footage in a good HD environment.

No, that's not what I'm saying. I'm not saying anything like "the Z7 is rubbish, and the EX is fantastic".

What I AM saying is that the front end difference between a Z7 and an EX is likely IMO to be greater than the difference between the 35Mbs codec and something like the 50 or 100Mbs codec. Hence, if you want to spend money on improving the quality of your Z7s output, I suspect it would be far more cost effective to upgrade to an EX rather than get a nanoFlash for it.

Originally Posted by Steve Phillipps

I have always assumed this is something to do with the codec and the reason why the 100 mb/s 422 type codecs are preferred for broadcast.

Not quite - the EBU recommendations are as a proposed minimum for future acquisition, and they specifically state the minimums to be 100Mbs for an I-frame codec, 50Mbs for a long-GOP codec, the two reckoned to give equivalent quality. (The benefit to long-GOP is lower bitrate, the downside more processing needed to edit etc, in both cases for a given level of quality. It would be totally wrong to describe either as "better" than the other - the advantages of one are the disadvantages of the other.)

For top end acquisition, money no object, it's likely that something better may be preferred, HDCAM-SR being an obvious example.