DV Info Net

DV Info Net (https://www.dvinfo.net/forum/)
-   Sony HVR-Z1 / HDR-FX1 (https://www.dvinfo.net/forum/sony-hvr-z1-hdr-fx1/)
-   -   FX1 real world resolution (https://www.dvinfo.net/forum/sony-hvr-z1-hdr-fx1/33201-fx1-real-world-resolution.html)

Simon Wyndham October 9th, 2004 06:54 AM

FX1 real world resolution
 
Okay first off contrary to what people might think of my opinions of HDV, I DO want to be able to shoot HD. I just think it's too good to be true at the moment.

I have just been thinking some more, especially with regard to obtaining a film look combined with the information that the FX1 CCDs only actually sample 960 16:9 pixels across and then convert that into the HD full spec picture.

This would mean that in terms of actual effective real resolution the camera is only resolving 960 lines across compared to 720 of, say Digi-beta. It's still good mind you, but not as good as it would first seem looking the initial frenzy over the camera. So, okay, 960 lines is still far better than the 500 of DV. Twice as good in fact.

But the real difference comes with the vertical resolution. If you want a film look, which I think many FX1 users will want as they will buy the camera for independant movie making, the picture will have to be deinterlaced.

Now I know there is a lot of talk about DVfilmmaker. Personally I find that and similar software gives an odd look. And besides, if the entire picture is moving DVfilmmaker still deinterlaces the whole picture.

So this still means that you only get half the effective vertical resolution.

This will mean that in terms of effective progressive scan resolution the FX1 will only produce a 960x540 image compared to a 720x576 (PAL) image of SD.

Someone told me that the FX1 produces a better picture already than the Sony XDCAM I am currently considering. However the XDCAM has superior broadcast quality optics and picture adjustment capapbilities as well as low light performance. Given that the effective resolution of the FX1 is not as great as it seems I don't think that there will be as huge a difference between high quality originated SD footage upconverted to HD (assuming it is progressive scan) and the FX1 deinterlaced.

Further to this I don't think there will be anywhere near the difference in quality between downconverted FX1 footage on DVD and high quality SD footage as a result either.

Don't take this as nay saying. I do want HDV to be accesible, but I am just looking at a real world view of the FX1 rather from the point of just accepting everything on face value.

Some of you on these forums have made points that have almost made me consider waiting for the FX1's pro version. So I looked into the specs a lot more carefully and that is what I have found. But feel free to correct me if I am wrong (no flames though).

Chris Hurd October 9th, 2004 07:43 AM

No flames here, but I think you're making a mistake with your assumptions. You're looking at specs and numbers and technical data. What you should be doing instead is actually using the camera, physically, and reserve your judgement for actual hands-on experience. Because the numbers really aren't telling you anything. You're trying to draw conclusions based on the published specifications, but such conclusions have no basis in fact whatsoever -- because you did not derive those conclusions empirically. You're just looking at numbers on paper. You need to actually try the thing out first, and then pronounce it dead or alive. Since you're considering XDCAM, you really should contact your Sony dealer and arrange a side-by-side demo. They'll be more than happy to accomodate you.

For now, you don't really know until you've actually shot with this camera. The good news is, if for some reason you're not able to try out this camera, you should still keep checking this forum because we'll be hearing from those who have.

Speculation achieves nothing. Experience is the arbiter around here. And you're in the right place, as we've set up this forum for people to share and compare their actual hands-on experiences. Hope you can see where I'm coming from.

Simon Wyndham October 9th, 2004 08:06 AM

Chris, pixels are pixels. I've done enough work with computer graphics to know the effects of up sampling and downsampling. In this case although I cannot give a conclusive opinion (which I didn't BTW, which you are trying to say I did), I can take the numbers and make a preliminary assumption.

It is a fact that the FX1 only samples 960 pixels across. It is a fact that if you deinterlace the picture it will only give 540 effective lines. Those are facts. And I know from all my years in video what that will look like.

My point, which you seem to have missed completely is that I would like to know how it's resolution compares to a high quality SD camera considering that in film looked terms the FX1's REAL WORLD resolution leap isn't as much as some people have been saying.

I'm being a realist here Chris. I'm right in the middle of arranging an 18 grand loan for a new camera. Do you honestly think I want to spend that kind of money if a 3 grand camera can give me a superior picture?!!

I am using all my experience of working in video and graphics and having done years of converting between various formats, and working with still pictures to come to some sort of idea of what the FX1 picture will be like (and yes I have downloaded the FX1 footage available online).

The fact is that the FX1's HD picture is upsampled. I can upsample a broadcast camera's picture too, and have more picture control from the camera, as well as exceptional colour rendition etc.

You say not to go on technical specs. But the fact of the matter is that people are comparing it to the technical specs of DV!

So I'm coming to it from the point of view of not only comparing technical specs, but also trying to make the point that the broadcast optics of the XDCAM compared to the cosumer optics of the FX1 might even things out if you take into account the technical specifications of both side by side.

Chris Hurd October 9th, 2004 08:38 AM

<< I can take the numbers and make a preliminary assumption. >>

No, you can't. Or put another way, you could, but you'd be wrong.

The single worst mistake you could make is to develop an assumption based on the numbers. You don't know what it looks like. You haven't seen the image. And that's what really matters.

Simon, if you're seriously considering XDCAM, then please allow me to make a friendly suggestion: stop wasting your time with HDV. If you're budgeting for XDCAM, then go with it. It's not a question of whether or not the Sony HDV camera produces an image which is "superior" to XDCAM. These are two completely different formats, two entirely different levels of gear, two completely different levels of expense. XDCAM will allow you a much greater range of flexibility with regard to lenses, camera controls, power and so much more. All of the benefits of that level of gear vastly outweigh any marginal (if it exists at all, it will be only slightly marginal) difference in image quality from the FX1.

People tend to get hung up on superlatives and that's a mistake. A word like "superior" is thrown around as if the difference is night and day. In actuality to most people any difference is going to be very subtle. Both XDCAM and HDV produce remarkable image quality. There's a much greater difference in the operational and practical aspects of these two formats than there is in the image quality. If you're budgeting for XDCAM, then you need to buy XDCAM.

These are business tools which should be earning back their expense for you within 60 to 90 days at the most so the cost is not that big of a deal. What matters is, developing a business plan to attract the right type of clients who can afford your XDCAM production package and then delivering them the high quality services that this format can produce. If you can do that -- and based on your stated experience, I believe you can -- then you don't need to be wasting your time considering a $3000 camcorder.

Simon Wyndham October 9th, 2004 08:57 AM

Thanks Chris.

One reason why I have been so concentrated on all these HD threads is because I wanted to get to the truth. What you have said about the XDCAM I have suspected already, along with the other benefits of the camera.

The thing I have been worried about is that to a potential client the numbers game with regard to HDV might be more tempting. For example, could I, equipped with an XDCAM and all the benefits of that camera, be ousted out of a corporate job because a wet behind the ears kid in the area has suddely started offering his services with an FX1?

That's been my worry regarding the job market value of the XDCAM.

Chris Hurd October 9th, 2004 09:16 AM

I'd look at it this way, Simon -- if you have an XDCAM package and all your production experience, and you get bumped out of a corporate gig by some kid with an HDV camera, then you probably didn't want to work for those folks anyway.

There's a certain level of corporate production planning that wouldn't dream of hiring anyone who did not have a pro package and years of experience. That's who you want to work for. You've got to find those people! And then this becomes, like so many other great topics here at DV Info Net, a question of real-world business practices more than a technical format discussion.

Simon Wyndham October 9th, 2004 09:29 AM

That is true. Although many companies cannot tell hi8 from Digi Beta. So someone offering HD through an advert might well pursuade some companies to try them out even if they don't need it.

But yes, I need to come back into the real world and realise that the XDCAM does stuff that simply isn't possible with the FX1 in terms of picture control etc (it also looks cooler ;-) )

Barry Green October 9th, 2004 10:34 AM

Re: FX1 real world resolution
 
Quote:

Originally posted by Simon Wyndham

This would mean that in terms of actual effective real resolution the camera is only resolving 960 lines across compared to 720 of, say Digi-beta. It's still good mind you, but not as good as it would first seem looking the initial frenzy over the camera. So, okay, 960 lines is still far better than the 500 of DV. Twice as good in fact.
Your basic premise here is flawed. First, DigiBeta doesn't have any higher resolution than DV (as far as lines of resolution; obviously it has higher color resolution). Both formats record 720 pixels across. Both formats are rated as 540 lines. Both formats record in an approximately 720x480 grid (DigiBeta uses 720x486, DV uses 720x480).

Is there a difference between how they look? Of course there is, a huge difference. The Digital Betacam camera head is going to be a $50,000 camera, capable of resolving 850 lines, etc (even though the recording format can only record 540 lines). It will look quite different.

But if you were just going off specs, saying "DV is 720 pixels across, and DigiBeta is 720 pixels across, DV is 540 lines of res, and DB is 540 lines of res" then you wouldn't expect there to be much difference, would you? But there is.


Regarding the FX1: speculation is merely speculation until we see the recorded image. The CCD's are apparently 960 pixels across, but they're also pixel-shifted, which will likely result in a full 1440 pixel image. Arguing numbers and statistics on paper is all fine and dandy, but if the resolution chart comes back showing 1440 pixels per line clearly and cleanly resolved, then who cares how many pixels there were on the CCD? What matters is what the picture truly, actually looks like. And we haven't seen that yet, although we should be able to answer that in about a month when the camera comes available.

Simon Wyndham October 9th, 2004 10:57 AM

I was going to let this go. But as a last statement I should point out that the actual picture size for DV is 720 across, but the actual format is only capable of 500 resolved lines across.

A Digi-beta camera on the other hand does in fact record a full 720 lines across.

Boyd Ostroff October 9th, 2004 11:44 AM

<<<-- Originally posted by Simon Wyndham : I should point out that the actual picture size for DV is 720 across, but the actual format is only capable of 500 resolved lines across.. -->>>

Unless I'm not understanding you, I think this is wrong. The horizontal resolution specs are based on a square sample of the image as displayed on an NTSC monitor. Therefore you need to take into account the pixel aspect ratio in your calculation. Vertical resolution is obviously 480 lines. So you divide 480 / 0.9 = 533 to get an equivalent number of horizontal pixels for DV25. For digibeta it would be 486 / .9 = 540. These would be the theoretical maximum horizontal resolutions for the formats.

Simon Wyndham October 9th, 2004 12:52 PM

I think we are confusing vertical with horizontal. I live in PAL world, so to clarify PAL DV is 500x576 resolved lines although the DV format is stored as 720x576. PAL Digibeta is 720x576. In other words the DV camera only samples 500 lines across (roughly speaking) whereas Digibeta samples the full 720.

But yes, I understand what you are saying about the aspect ratio of the pixels. I was only talking in general to illustrate that digibeta is a higher resolution than DV.

Simon Wyndham October 9th, 2004 01:06 PM

Sorry brain farting. I need some sleep!

Barry Green October 9th, 2004 02:47 PM

Simon, your premise is not accurate.

You're confusing pixel resolution with the way resolution is measured on video cameras. Video cameras use TV Lines of resolution. They are not counting the number of pixels recorded horizontally, or vertically. They're counting the # of pixels that can be recorded horizontally IN A SQUARE PATCH, as related to the height of the frame (as Boyd was trying to explain).

So: DV records 720 x 480, at a pixel aspect ratio of 4:3. To get a square patch you have to take 4/3's of the height. The height is 480, so 480 x 4 / 3 = 540. The maximum possible TV Lines of Resolution that can be recorded on the DV format is therefore 540 lines of resolution.

The same is true of DigiBeta. DigiBeta records at 720 x 486.

Both formats are capable of resolving individual pixels at alternating spaces across the screen, both are capable of recording 720 individual, discrete pixels across. In fact, if you are recording a black and white image, you'll find that the SDX900 (in DV mode) and a Digital Betacam camera would record what looks like an identical picture.

DV, as a format, is 540 lines of resolution when measured as TV Lines. Digital Betacam is also 540 lines of resolution.

DV, as a pixel array, is 720 x 480 (in NTSC). Digital Betacam is 720x486.

Simon Wyndham October 9th, 2004 02:53 PM

Aiyah Barry, read my last post. :-)

Michael Struthers October 12th, 2004 03:04 PM

Symon, if you've got 18k to blow, just buy a Sony FX-1 and use it. If you don't like it, sell it on ebay.

You could probably buy an FX-1 out of Japan after the 15th of October.


All times are GMT -6. The time now is 02:26 AM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2024 The Digital Video Information Network