View Full Version : 720p and image brakedown


John Trent
May 14th, 2005, 09:44 AM
I've read alot about the HDV 1080i from Sony not being able to handle fast movements and handheld shots without image brakedown, but what about the HDV 720p material from JVC? I suspect an opinion about the HD100u, and it's abilities to handle motion couldn't be formed from the limited footage at NAB. But what about the HD1u & HD10u, don't they have the same 19 bitrate, 6 GOP, and progressive imaging as the HD100u? So how do they handle fast motions and pans?

Ron Evans
May 14th, 2005, 02:30 PM
John , I have had my FX1 since early December 2004 and for all the video I have shot( about 6 hours HDV ) I see no problem with fast motion or pans as fast as I am prepared to use. I use Sony Premium tape exclusively and have also not seen any drop outs. I have used the HDV mainly for my own family use, chasing one grandson around at close range, which definately leads to fast pans at close range etc.You probably read a lot of info from people who don't own the FX1 and may not have even seen one!!! I have shot about 18 hours of DV and this too is excellent as far as I am concerned. The other thing you may have read is that the FX1 is not as good as XXXXXX in low light. The FX1 is useable at up to 12db of gain (or even 18db for something like a family party with little grain) but most comparisons are done at 0 db. For instance this gives the impression that the DVX100 is more sensitive, the problem is that the DVX100 is unusable at much above 0db and when this is taken into consideration it is my opinion that the FX1 is a lot more usable in low light. ( I do know the DVX100 having rented it a few times). I also have a Sony TRV50 and by comparison when I can't see anything on the TRV50 the FX1 at 18db provides a picture that is very close to what my eyes are seeing. At the wedding of one of my daughters friends the FX1 was OK until they turned most of the lights off for dancing with the crystal ball and flashing lights. To be honest it was pretty dark by then. The FX1 is good value for money, is a good DV camera with plenty of manual controls and provides for the future in HDV. IT is not intended to be a killer professional camera so comparisons with professional HD cameras etc is also ludicrous.

Ron Evans

Mark Grant
May 14th, 2005, 07:40 PM
I've read alot about the HDV 1080i from Sony not being able to handle fast movements and handheld shots without image brakedown,

I've seen some stuttering on pans with my Z1, but I'm pretty sure that's due to watching the footage deinterlaced on a PC monitor (since I don't have an HDTV). It looks OK when I use the analog outputs to display the footage downconverted on a PAL TV.

Certainly I haven't seen any sign of blatant compression artifacts yet: the apparent stuttering is the only real issue that's come up so far.

I also agree on the low-light comments above. The Z1 isn't as good as the best DV cameras at 0db, but even 18db gain isn't too noticeable (whereas on my old TRV900, anything above 6db was barely usable).

John Trent
May 15th, 2005, 09:44 AM
Thanks guys. It's true Ron, I admit my information about the Sony is second-hand from the web. The Sony store in Chicago where I used to go to check out the new gear disappeared over night, so I am relying on the (mis) information I get on the boards.

If the Sonys' had progressive scan I would already own one. There will soon be four prosumer camcorders with 24/30p, with a July announcement from Canon expected to bring another. When will Sony join in? I mean, aren't they getting embarrassed? Every other company is passing them by. If you told me, two years ago, this would happen, I wouldn't have believed you.

I do think Sony's low noise gain (and extreme reliability) is something that will be sorely missing on their competitors' models. That said, I feel Sony is forcing me to look at the competition precisely because of what they are lacking - 24/30p and decent gamma controls.

Ron Evans
May 15th, 2005, 10:28 AM
Hi John ,
I have no use for progressive so its of little interest to me. When 60P comes along I will get more interested but I like the fluid motion of interlace and detest the stutter of 24P. There are quite a lot of controls on the FX1 and Z1 in the PP menu of six presets that can be adjusted you should look at these in some detail before making your decision.

Ron

Mark Grant
May 15th, 2005, 10:39 AM
I mean, aren't they getting embarrassed? Every other company is passing them by.

Yeah, Sony must be really embarassed: Z1s are selling so well that prices are going _up_, at least here in the UK. The store I bought mine from is now charging $100 more, less than two weeks later... and when I collected it they said that Z1s were flying off the shelves as fast as they could get new stock in. The other online stores I checked are also charging more than they were when the camera was released.

I don't think Sony have anything to worry about, to be honest. There's no 1080/24p camera in the same market, and most people buying Z1s and FX1s aren't going to want to shoot 24p in the first place... all you get is stuttery video that still doesn't look much like film.

The only real competition if you want 1080 resolution is the HVX200, which a) doesn't exist and b) will be stupidly expensive and complex to run compared to an HDV camera if and when it is released... Sony can start to worry about that when they release the FX2/Z2.

John Trent
May 18th, 2005, 08:58 AM
I've read, and maybe it's just the Panasonic propaganda that flys pretty thick on these sites, that the DVX100A is outselling the Sony HDV camcorders by a three fold.

To answer my own post: I've just read an Adam Wilt article in the current issue of DV magazine about the problems of posterization, blocking up, and noise he encountered with HDV when trying to shoot high detail, or complex, abrupt, or quick motions. He seemed to lump the 720p HDV in with the 1080i HDV material without being specific.

There's a tendency on these types of boards for people to get overly impressed with spec numbers or with the number of dollars they've spent on a product that seems to erase all objectivity as to the problems that exist. Just check out the justifications about the size and price of the P2 media on the HVX200 sites. I mean...c'mon my car costs less then two P2 cards.

Mark Grant
May 18th, 2005, 09:23 AM
There's a tendency on these types of boards for people to get overly impressed with spec numbers or with the number of dollars they've spent on a product that seems to erase all objectivity as to the problems that exist.

There's also a tendency to write off anything new based on artificial 'tests', purely because it's new and 'that's not how it's done'. I remember the same kind of claims being made about how awful DV was when it was released, and how it would never be used in place of Beta SP. I'm sure that within their ivory towers and artificial testing schemes that they were right, but DV sure replaced a lot of Beta SP cameras over the next few years.

John Trent
May 18th, 2005, 11:20 AM
There's also a tendency to write off anything new based on artificial 'tests', purely because it's new and 'that's not how it's done'.

I'm not sure what your talking about, Mark. Adam Wilt knows what he's talking about. His opinion is valued by everyone I've ever heard of. I can't remember his views being discounted so casually. Adam Wilt seems fair and not a reactionary, and I, for one, pay attention when he speaks - I may not understand everything he says, but when an expert weighs in on a subject, I consider his merit. He's been checking out the HDV awhile and with multiple systems. I suggest you check out DV magazine.

Mark Grant
May 18th, 2005, 12:00 PM
I haven't read the article and don't particularly want to pay to do so: on the other hand, I _do_ have a Z1 and haven't noticed any serious issues with it yet the way that I use it. Then again, I'm not spending much time "trying to shoot high detail, or complex, abrupt, or quick motions"... if I did, I'd have bought a different camera.

The point is this: sure, HDV isn't as good as a $100k Sony HDCAM. Yes, there are limits beyond which you'll see problems. But provided you don't go beyond those limits, it looks fine.

Comparing a Z1 to a $100k HDCAM is just as silly as comparing a VX1000 to a $50k Betacam. Sure, push the VX1000 beyond the sensible limits and the Betacam looked better, but in 99% of cases it was perfectly acceptable... which is why DV ate up the bottom end of the Beta market.

Ron Evans
May 18th, 2005, 12:43 PM
I have to agree with Mark and to repeat my earlier comments. I have not seen any artifacts in the way I use the camera. I have ONLY used Sony Premium tape ( mixing tape is bad news so any problems that follow this practice are very dubious), have panned around as fast I would want to without falling down myself, and taken shots of water around my boat and leaves blowing in the wind in my back yard. None of which has shown any artifacts on my Sony HighScan HD monitor. What I haven't done is captured a still and blown it up on a progressive displayed PC monitor. Doing this will almost certainly find something that looks like a defect, which may or may not be caused by the progressive algorithm used to display on the PC. However no one watches TV this way, do they? Sony's system is an interlaced system at 1080i BEST viewed on a HD CRT monitor. I say best viewed because interlace is predicated on using the phosphor decay of the CRT and the way this interacts with the ones eyes and brain to create a picture. Creating a progressive image from this is more dependent on the progressive algorithm than the quality perceived by the viewer of the interlaced image on a CRT. In the meantime I love my FX1 whatever Adam Wilt says and I too find Adam a very useful source of information.

Ron Evans

John Trent
November 27th, 2005, 12:21 PM
Okay, I've seen for myself. Local BEST BUY and CIRCUIT CITY stores have the Sony HC1. Every pan turns the image into a soft, motion blurring mess. The salesman quickly grabbed the camera away and increased the shutter speed (above the standard 60) to decrease the effect. I saw it plugged into a hi - def tv, not just the viewfinder / lcd. I took it off autofocus which also helped but at 60 shutter speed the mess was still noticable. I've now seen three different cameras behave this way.

So ... new questions: Is this because the HC1 uses a CMOS sensor or does the FX1 / Z1 have the same problem?

I saw no macro - blocking; is this because it only shows up on tape playback?

And most importantly -- how does the JVC H100U 720p hold up? Everybody knows about the camera's problems but I just read passing comments about the mpeg compression artifacts. Does the image go into a soft, motion blurring mess on every pan? Does it block up?

Thanks.

Douglas Spotted Eagle
November 27th, 2005, 12:29 PM
I saw no macro - blocking; is this because it only shows up on tape playback?


Thanks.

If he plugged in the RGB output to a monitor, this is pre-compression, and is a 4:2:2 uncompressed signal coming out.
If shutter speed is low, you'll definitely get blur/smear/ and maybe macroblocking. This is partially due to compression, partially due to CMOS, and partially due to how the camera interprets contrasts in a fast pan.
First, fast pans aren't possible with HDV cams in slow shutter speeds, it needs to be panned more like a film cam.
Second, be sure stabilization is off, auto focus is off, and you'll see a much nicer image.
The Z1 is much better for this sort of test examination.

John Trent
November 28th, 2005, 10:07 AM
Thanks, Douglas.

I forgot to mention I did try it without the optical stabilization. I had it set at 60th shutter speed, for the most part, but I did try the 30th shutter speed and the cine effect modes just to see if they were usable. I'm glad to hear the CMOS chip is partly to blame.

Have you seen the JVC H100 720p stuff? I'm actually not interested in the camera, I just want to know how it handles the MPEG compression and what, if any, artifacts show up.

What I'm really interested in is a FX2/Z2 with 720p (if the format is artifact free). I keep hoping Sony will join the 24p/30p camera crowd soon. They are the only company not to have a progressive scan camcorder on the market. Maybe they'll release a 1/3 ccd 24p/30p camera once they start producing Blu-Ray camcorders.

I've always been a Sony guy but unless they announce something by January I'll jump ship to Panasonic. Your "in" at Sony, right(?), but you've probably signed some non-disclousure aggreement. Could you at least give a guy a hint, like say, -- "I'd wait to jump that ship...".

Thanks.