Need some clarifications

Heath McKnight · September 25th, 2003, 08:35 PM

I wish I could afford ND filters.

heath

Charles Henrich · September 26th, 2003, 01:24 AM

Just a note about "1080p" projection in theaters. Until just a few months ago there were no projectors capable of displaying a true 2k image (1920x1080 or better). The very newest cinema DLP chips from TI can do it, but I dont think you'll find any of these in any theatre yet. (Unless its being built now, granted this is conjecture). The most common ones out there are going to be 1280x1024. Since registration is a non-issue of course, they appear much crisper than comparable film projection. That is in your local megaplex, not a properly calibrated and maintained 35mm projector. But those dont exist commonly. So anyone whose seen a DLP presentation is looking at essentially the resolution of the JVC Camcorder.

Jay Nemeth · September 26th, 2003, 03:48 AM

It's true that the 2K chips will be a huge improvement for DLP, but I have always preferred the D-ILA projectors which have been at 2K resolution for some time. Unfortunately, there is only DLP Cinema in Las Vegas right now.

When pictures such as "Attack of the Clones" or "Once upon a time in Mexico" are framed 2.35 with the Cinealta, the resulting image is 810 lines vertical which is a reproduceable number with current D-Cinema. I haven't seen a picture that was framed 1.85, but that would result in 1036 vertical lines, very close to SXGA. And of course, we know that Cinealta produced pictures can't reach 1920 horizontal lines anyway. All of the current Digital Cinema projectors accept SMPTE 292M standards and have much more going for them versus industrial DLP projectors. Things such as 12 ft-L of light output on a cinema sized screen, over 1000 to 1 contrast ratio, and the fact that they have a color gamut matched to film versus a television color scheme are what motivates me to screen our project this way.

Jon Fordham · September 26th, 2003, 06:24 AM

<<So anyone whose seen a DLP presentation is looking at essentially the resolution of the JVC Camcorder.>>

WHOA! Charles, hold on a minute. That's like saying if you've seen a DVD then you're looking at the resolution of MiniDV.

While it's true that horizontal resolution specifictions and pixel ratios may be similiar, the image quality can't be assertained by such.

For instance, a DVD that is created from a 1080 Digital Master of a 35mm film originated image is going to look drastically different in terms of image quality and resolved clarity than a DVD that is authored from a 525/60i MiniDV originated image. Both DVD's will have the same resolution once on disc. But just because both DVD's will have the same resolution specs, doesn't mean they're going to look anywhere near the same.

Resolving power of the origination format has nothing to with the resolving power of the screening format.

Heath McKnight · September 26th, 2003, 07:26 AM

Allegedly the local theatre near my old house is all digital, at least according to a buddy of mine. I walked into a DLP theatre in L.A. when I was working out there (FINDING NEMO, best movie of the year I've seen--AMERICAN SPLENDOR is next!), and it seemed dark. I hear it's because theatres are cheap with lights in the DLP.

heath

ps-If the local theatre is now all digital, I'll go see ONCE UPON A TIME IN MEXICO and report in TOTEM.

Charles Henrich · September 26th, 2003, 09:47 AM

Jon, I was talking about technical details. The JVC camera can absolutely resolve 1280x720 pixels. Thats what the CCD produces. Granted the lenses arent panavision, we're not talking 3 35mm CCD arrays either. The quality of the data in those pixels is a different story ;). My original point was that if you firewire off frames from your JVC and look at them on your computer, when projected by a cinema dlp system will show up exactly (but larger) as you see. If you have higher resolution images than those, the projector is going to interpolate the image down to fit in that resolution (and usually hardware interpolation is pretty poor relativly speaking).

Jay, good to hear about the D-ILA projectors. I was under the (mistaken?) impression that theatre's were only using the DLP products (at least here in California thats all I've ever seen mentioned). Whose projectors has the matched color gamut? That rocks! Now to get one for my home.. :)

Jon Fordham · September 26th, 2003, 10:19 AM

According to the "technical details", wouldn't it be more appropriately stated that the recording standard of 720 HD has a pixel aspect ratio of 1280x720? The resolving power of the CCD is a different story.

For instance, in memory card recording mode, the camera can produce 1280x960 images.

The CCD only uses 840,000 effective pixels in HD mode. I think that falls short of filling the entire 1280x720 frame with a 1:1 pixel ratio. But, I may be mistaken. Someone will have to check the math.

We're debating very minute details I know. But clarification is what this thread is all about isn't? Can someone check the math and clarify the "effective pixel count" in relation to the "pixel aspect ratio"?

Heath McKnight · September 26th, 2003, 11:00 AM

I just want to be able to shoot good stuff, so I'm in agreement. I wanted Clarification, not scientific specifics. If it looks good, that's all I need. Having some thorough knowledge is good, but I hate being chastised for not knowing EVERY specific, electronic thing about a camera.

heath

Jay Nemeth · September 26th, 2003, 11:05 AM

Regarding D-ILA:

When Phantom Menace came out and Digital cinema was just getting off the ground, the Hughes-JVC D-ILA was in several venues and there was much debate between which was better, D-ILA or DLP. I saw both and D-ILA seemed to have better detail but DLP had better colorimetry. DLP eventually became the popular system, I don't know if there are any active D-ILAs in any theater.

The color gamut issues were discussed in the early days when the systems were being developed. Cinematographers especially, wanted the same saturations and gamma curves of film and didn't want their work seen on huge "televisions". I believe the electronics that drive the DMD and possibly dichroics is how this is achieved. I once read a technical report from TI about this, but don't recall. I thought all Digital Cinema projectors were this way.

Regarding the JVC camera resolution:

Goto http://www.jvc.com/main.jsp# and click on the GR-HD1 window, then click on "accessories/specifications" then click on "specifications" and it lists the Hor. / Ver. Res. as 700 / 650 lines. This seems really low for this sensor and some of the other modes look low also, although some look correct such as 480p. I couldn't find this info on the JY-HD10u page. I'm not sure what to make of this.

Jay

Eric Bilodeau · September 26th, 2003, 03:29 PM

The number of pixels of a 1280X720 image is 921 600 pixels (it is pretty simple math: 1280 X 720) so indeed, the image sensor of the JVC is not full resolution but in HD, it is much less noticeable than in SD (like the XL1 case). For example the varicam has a 1 000 000 pixel set of 3 CCDs so it covers for the entire definition (even a bit more). As a matter of fact, the signal on the JVC is like an upconversion of a lower (not much lower, like close to 1222X687), so the image is pretty close in terms of definition to 1:1, it is 0,91:1. It is certainly not something you can see as obvious, it is very close to true 1280 by 720 definition.

Jon Fordham · September 26th, 2003, 07:10 PM

<<For example the varicam has a 1 000 000 pixel set of 3 CCDs so it covers for the entire definition (even a bit more).>>

Actually (and I know this is being picky and bordering on ridiculous but), according to the specifications listed in my owners manual for the Panasonic aj-HDC27Fp Varicam, the total number of pixels is 1370x744, indeed 1 million (or 1,019,280 to be exact). However the total number of effective pixels on the 2/3" IT CCD's is exactly 1280x720.

OK, I'll stop nit picking now...

Heath McKnight · September 26th, 2003, 11:04 PM

<<<-- Originally posted by Jon Fordham : <<For example the varicam has a 1 000 000 pixel set of 3 CCDs so it covers for the entire definition (even a bit more).>>

Actually (and I know this is being picky and bordering on ridiculous but), according to the specifications listed in my owners manual for the Panasonic aj-HDC27Fp Varicam, the total number of pixels is 1370x744, indeed 1 million (or 1,019,280 to be exact). However the total number of effective pixels on the 2/3" IT CCD's is exactly 1280x720.

OK, I'll stop nit picking now... -->>>

Jon, you're truly a DIT.

heath

September 25th, 2003, 08:35 PM	#31
Heath McKnight MPS Digital Studios Join Date: Apr 2003 Location: Palm Beach County, Florida Posts: 8,531	I wish I could afford ND filters. heath __________________ My Final Cut Pro X blog

September 26th, 2003, 07:26 AM	#35
Heath McKnight MPS Digital Studios Join Date: Apr 2003 Location: Palm Beach County, Florida Posts: 8,531	Allegedly the local theatre near my old house is all digital, at least according to a buddy of mine. I walked into a DLP theatre in L.A. when I was working out there (FINDING NEMO, best movie of the year I've seen--AMERICAN SPLENDOR is next!), and it seemed dark. I hear it's because theatres are cheap with lights in the DLP. heath ps-If the local theatre is now all digital, I'll go see ONCE UPON A TIME IN MEXICO and report in TOTEM. __________________ My Final Cut Pro X blog

September 26th, 2003, 11:00 AM	#38
Heath McKnight MPS Digital Studios Join Date: Apr 2003 Location: Palm Beach County, Florida Posts: 8,531	I just want to be able to shoot good stuff, so I'm in agreement. I wanted Clarification, not scientific specifics. If it looks good, that's all I need. Having some thorough knowledge is good, but I hate being chastised for not knowing EVERY specific, electronic thing about a camera. heath __________________ My Final Cut Pro X blog

September 26th, 2003, 03:29 PM	#40
Eric Bilodeau Major Player Join Date: Jun 2003 Location: Chicoutimi, Canada Posts: 334	The number of pixels of a 1280X720 image is 921 600 pixels (it is pretty simple math: 1280 X 720) so indeed, the image sensor of the JVC is not full resolution but in HD, it is much less noticeable than in SD (like the XL1 case). For example the varicam has a 1 000 000 pixel set of 3 CCDs so it covers for the entire definition (even a bit more). As a matter of fact, the signal on the JVC is like an upconversion of a lower (not much lower, like close to 1222X687), so the image is pretty close in terms of definition to 1:1, it is 0,91:1. It is certainly not something you can see as obvious, it is very close to true 1280 by 720 definition. __________________ Eric Bilodeau video SFX,DOP ___________________ http://www.fictis.net info@fictis.net

September 26th, 2003, 11:04 PM	#42
Heath McKnight MPS Digital Studios Join Date: Apr 2003 Location: Palm Beach County, Florida Posts: 8,531	<<<-- Originally posted by Jon Fordham : <<For example the varicam has a 1 000 000 pixel set of 3 CCDs so it covers for the entire definition (even a bit more).>> Actually (and I know this is being picky and bordering on ridiculous but), according to the specifications listed in my owners manual for the Panasonic aj-HDC27Fp Varicam, the total number of pixels is 1370x744, indeed 1 million (or 1,019,280 to be exact). However the total number of effective pixels on the 2/3" IT CCD's is exactly 1280x720. OK, I'll stop nit picking now... -->>> Jon, you're truly a DIT. heath __________________ My Final Cut Pro X blog

September 26th, 2003, 01:24 AM	#32
Charles Henrich New Boot Join Date: Aug 2003 Location: LA, CA Posts: 14	Just a note about "1080p" projection in theaters. Until just a few months ago there were no projectors capable of displaying a true 2k image (1920x1080 or better). The very newest cinema DLP chips from TI can do it, but I dont think you'll find any of these in any theatre yet. (Unless its being built now, granted this is conjecture). The most common ones out there are going to be 1280x1024. Since registration is a non-issue of course, they appear much crisper than comparable film projection. That is in your local megaplex, not a properly calibrated and maintained 35mm projector. But those dont exist commonly. So anyone whose seen a DLP presentation is looking at essentially the resolution of the JVC Camcorder.

September 26th, 2003, 03:48 AM	#33
Jay Nemeth Regular Crew Join Date: Jul 2003 Location: Las Vegas, NV Posts: 64	It's true that the 2K chips will be a huge improvement for DLP, but I have always preferred the D-ILA projectors which have been at 2K resolution for some time. Unfortunately, there is only DLP Cinema in Las Vegas right now. When pictures such as "Attack of the Clones" or "Once upon a time in Mexico" are framed 2.35 with the Cinealta, the resulting image is 810 lines vertical which is a reproduceable number with current D-Cinema. I haven't seen a picture that was framed 1.85, but that would result in 1036 vertical lines, very close to SXGA. And of course, we know that Cinealta produced pictures can't reach 1920 horizontal lines anyway. All of the current Digital Cinema projectors accept SMPTE 292M standards and have much more going for them versus industrial DLP projectors. Things such as 12 ft-L of light output on a cinema sized screen, over 1000 to 1 contrast ratio, and the fact that they have a color gamut matched to film versus a television color scheme are what motivates me to screen our project this way.

September 26th, 2003, 06:24 AM	#34
Jon Fordham Major Player Join Date: Sep 2003 Location: New York, NY Posts: 242	<<So anyone whose seen a DLP presentation is looking at essentially the resolution of the JVC Camcorder.>> WHOA! Charles, hold on a minute. That's like saying if you've seen a DVD then you're looking at the resolution of MiniDV. While it's true that horizontal resolution specifictions and pixel ratios may be similiar, the image quality can't be assertained by such. For instance, a DVD that is created from a 1080 Digital Master of a 35mm film originated image is going to look drastically different in terms of image quality and resolved clarity than a DVD that is authored from a 525/60i MiniDV originated image. Both DVD's will have the same resolution once on disc. But just because both DVD's will have the same resolution specs, doesn't mean they're going to look anywhere near the same. Resolving power of the origination format has nothing to with the resolving power of the screening format.

September 26th, 2003, 09:47 AM	#36
Charles Henrich New Boot Join Date: Aug 2003 Location: LA, CA Posts: 14	Jon, I was talking about technical details. The JVC camera can absolutely resolve 1280x720 pixels. Thats what the CCD produces. Granted the lenses arent panavision, we're not talking 3 35mm CCD arrays either. The quality of the data in those pixels is a different story ;). My original point was that if you firewire off frames from your JVC and look at them on your computer, when projected by a cinema dlp system will show up exactly (but larger) as you see. If you have higher resolution images than those, the projector is going to interpolate the image down to fit in that resolution (and usually hardware interpolation is pretty poor relativly speaking). Jay, good to hear about the D-ILA projectors. I was under the (mistaken?) impression that theatre's were only using the DLP products (at least here in California thats all I've ever seen mentioned). Whose projectors has the matched color gamut? That rocks! Now to get one for my home.. :)

September 26th, 2003, 10:19 AM	#37
Jon Fordham Major Player Join Date: Sep 2003 Location: New York, NY Posts: 242	According to the "technical details", wouldn't it be more appropriately stated that the recording standard of 720 HD has a pixel aspect ratio of 1280x720? The resolving power of the CCD is a different story. For instance, in memory card recording mode, the camera can produce 1280x960 images. The CCD only uses 840,000 effective pixels in HD mode. I think that falls short of filling the entire 1280x720 frame with a 1:1 pixel ratio. But, I may be mistaken. Someone will have to check the math. We're debating very minute details I know. But clarification is what this thread is all about isn't? Can someone check the math and clarify the "effective pixel count" in relation to the "pixel aspect ratio"?

September 26th, 2003, 11:05 AM	#39
Jay Nemeth Regular Crew Join Date: Jul 2003 Location: Las Vegas, NV Posts: 64	Regarding D-ILA: When Phantom Menace came out and Digital cinema was just getting off the ground, the Hughes-JVC D-ILA was in several venues and there was much debate between which was better, D-ILA or DLP. I saw both and D-ILA seemed to have better detail but DLP had better colorimetry. DLP eventually became the popular system, I don't know if there are any active D-ILAs in any theater. The color gamut issues were discussed in the early days when the systems were being developed. Cinematographers especially, wanted the same saturations and gamma curves of film and didn't want their work seen on huge "televisions". I believe the electronics that drive the DMD and possibly dichroics is how this is achieved. I once read a technical report from TI about this, but don't recall. I thought all Digital Cinema projectors were this way. Regarding the JVC camera resolution: Goto http://www.jvc.com/main.jsp# and click on the GR-HD1 window, then click on "accessories/specifications" then click on "specifications" and it lists the Hor. / Ver. Res. as 700 / 650 lines. This seems really low for this sensor and some of the other modes look low also, although some look correct such as 480p. I couldn't find this info on the JY-HD10u page. I'm not sure what to make of this. Jay

September 26th, 2003, 07:10 PM	#41
Jon Fordham Major Player Join Date: Sep 2003 Location: New York, NY Posts: 242	<<For example the varicam has a 1 000 000 pixel set of 3 CCDs so it covers for the entire definition (even a bit more).>> Actually (and I know this is being picky and bordering on ridiculous but), according to the specifications listed in my owners manual for the Panasonic aj-HDC27Fp Varicam, the total number of pixels is 1370x744, indeed 1 million (or 1,019,280 to be exact). However the total number of effective pixels on the 2/3" IT CCD's is exactly 1280x720. OK, I'll stop nit picking now...