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-   Canon XL and GL Series DV Camcorders (https://www.dvinfo.net/forum/canon-xl-gl-series-dv-camcorders/)
-   -   24p questions (https://www.dvinfo.net/forum/canon-xl-gl-series-dv-camcorders/34265-24p-questions.html)

Kevin Gilvear October 14th, 2004 01:13 PM

That's really nice, man.

Jean-Philippe Archibald October 14th, 2004 01:30 PM

Dennis, why are you using the 16X white lens instead of the 20X new fluorite lens?

Ralph Roberts October 14th, 2004 05:57 PM

Kewl, Dennis!

Love her expression when she sits down and looks at the pumpkin, this kid will go far. ;-)

Thanks for the footage.

--Ralph

Frederic Segard October 17th, 2004 02:40 PM

I'd be curious to find out if some filmmakers and 24p videographers add (well done) motion blur in post to further reduce the strobe effect?

Chris Chung October 19th, 2004 10:48 PM

No autofocus in 24P?
 
Is it true that XL2 has no autofocus in 24P?

Marty Hudzik October 20th, 2004 12:48 AM

It has it but it is really, really slow. Similar to Panasonic DVX100A in pogressive mode. They call it "focus assist". It has something to do with the reduced sample rate....normally samples 60i images, 60 per second. In 24P it is only getting 24 per second to adjust focus....so theoretically it will take over twice as long to find the focus.

Barry Green October 20th, 2004 02:18 AM

In 24P mode the CCD runs at 24Hz, vs. in interlaced mode when it's running at 60hz.

So the autofocus system, which is designed to work properly by getting 60 updates per second, is only getting 24 updates when in 24P mode.

It means it won't just take twice as long to find focus, it'll take MUCH longer, because with the updates coming more slowly, it'll likely overshoot its target much more frequently and then overcorrect and overcompensate, ad infinitum...

Adam Wilt tested a DVX in 24P mode on slow shutter speed (which further reduces the updates, I think he used 1/6 second which means the focus system was getting updated only 6 times per second). It took the camera 55 seconds to lock focus, something that 60i would have done in like 1/10 of a second.

So yes, focus assist is there, and no, it won't perform like "real" autofocus.

Dennis Hingsberg October 20th, 2004 09:39 AM

Jean-Philippe - I plan to use the XL2 mostly with the mini35 so I doubt the 20x lens will even make it out of Canon's box. I just sold my PAL XL1s and my XL2 update kit for the mini35 has arrived - so from here on in, its 35mm lenses for me.

Ralph - I tried doing a short film in the summer with her that I wrote but unfortunately ran out of time. I plan to reshoot it in the spring with the new XL2. As for the footage I posted of her, it seems dark when I view it on CRT so I might upload a brigher version. It looked fine on my LCD.

Chris Chung October 20th, 2004 11:14 AM

Thank you Marty and Barry,
I guess DVX100A has the same slow focus in 24P like XL2, right?

Imran Zaidi October 20th, 2004 11:43 AM

Yepper, the DVX100A has a slow autofocus in 24p mode. It would be nice if it was faster, but truly, you really should get a feel for fast manual focus. Helps avoid focus hunting mistakes that ruin an otherwise great shoot.

Does the XL2 have a numbered focus scale like the DVX? That's what really floats my boat with manual focusing on the DVX.

Marty Hudzik October 20th, 2004 12:01 PM

<<<-- Originally posted by Imran Zaidi : Does the XL2 have a numbered focus scale like the DVX? That's what really floats my boat with manual focusing on the DVX. -->>>

no sir....it does not have a numbered focus scale. Serious Bummer.

David Lach October 20th, 2004 03:03 PM

If you want to do manual focusing, buy the 16x lens. Even better, buy the 14x for $900 which will give you the manual iris to boot.

I don't know anybody who's serious about precisely manual focusing critical shots that would do that on one of those endless spinning rings like the ones on the Canon AF lenses or the DVX.

Marty Hudzik October 20th, 2004 03:24 PM

<<<-- Originally posted by David Lach : If you want to do manual focusing, buy the 16x lens. Even better, buy the 14x for $900 which will give you the manual iris to boot.

I don't know anybody who's serious about precisely manual focusing critical shots that would do that on one of those endless spinning rings like the ones on the Canon AF lenses or the DVX. -->>>

I agree with you in general but the numbering scheme on the DVX is pretty accurate if you make a mental note of where you are focusing. For example....when I was shooting talent that were moving say 10 feet in front of me I could focus and make a note that at 46 I was in focus for 10 feet away. Later.....if I have things all screwed up and I need to get back to a similar focus I can just whip it to 49 and know I am in the ballpark. fine adjustments from there.

On the XL if you have people 10 feet from you who knows where the heck you are in terms of focusing without turning the focus and watching to see what happens.

Keep in mind that both of these references are for run and gun manual filming and not "staged" scenes. Also.....this helps on the DVX as the numbers give a good reference as to what area you are focused in without having to look at the viewfinder....I mean....you have to look at the viewfinder to see the numbers and all....but to know you have a scene that is 5-6 feet away you already know the range of focus numbers for that distance.

Barry Green October 20th, 2004 05:19 PM

The DVX ring is different. It's repeatable. It acts exactly like a true manual focus ring, with the exception being no "hard stops" at infinity or MOD. But you can mark the lens barrel with tape marks for your start and end point, and endlessly repeat those marks, just like on a true manual focus lens.

And if you get the Century ring with hard stops, it becomes a completely functional full manual focus ring. It's in a completely different league from the endless-spinner focus rings on cameras like the PD170 and XL2's 20x lens.

Chris Chung October 20th, 2004 10:19 PM

Thanks for the footage.
great stuff.
love to see more.

William LiPera October 26th, 2004 09:15 AM

24p & progressive scan dvd
 
When playing a 24p xl2 clip burned to dvd in progressive scan then played with a progressive scan dvd player on a High definition tv with component in, is this truely playing 24p or is there some interlacing going on. Thanks , Bill

Joshua Starnes October 26th, 2004 09:28 AM

It's not exactly true 24p - but it's as close as you're going to get on a TV. The DVD player has to use a complex algorithm (If you do some searches through the DVD section, you'll see a lot of talk about 2:3:3:2 pulldown and the like, that is what they're talking about) to represent true 24p on a TV running off a 60hz power supply (I assume you're talking about NTSC - PAL is slightly different). What you're getting is 24p represented on a 30p monitor. It will be true progressive, there won't be any interlacing going on.

However, major Hollywood films shot on film have to put up with the same algorithm when they are put on DVD as well - so you don't have to worry about trying to find a better way to do it, because there isn't one. More to the point, the movement differences between 24p represented on a TV and projected from a film projector are invisible to the naked eye. Usually, if you originate in 24p, it's going to look like 24p on your TV.

I have heard the possibility (and maybe someone who knows more can illuminate?) that there will be TVs capable of showing true 1080 24p picture - but that's not a commercial reality right now.

David Lach October 26th, 2004 06:38 PM

I might be wrong, but I think progressive capable digital TVs (Plasma, LCDs) can display true 24p and don't need to be fed with 30p/60i, just like your standard CRT/LCD computer monitor can show true 24p motion without any kind of conversion.

Nick Hiltgen October 26th, 2004 07:52 PM

I don't think that progressive 108024P is possible yet on the tv's you're talking about. Only because the F900 is one of the few camera's that shoots in that particular format and even when it's being monitored there's too much information for a true progressive image it's actually a segmented frame. So I don't think so yet but it will happen soon.

AJ Silverman October 31st, 2004 09:48 PM

More 24p Questions
 
Thanks for any advice in advance. I have been editing since the heady days of Assymetrix DVP and Premiere 4.2 completing various projects over the years, mostly becoming an Adobe stalwart along the way. Well, I have made the big leap...and got myself a shiny new Canon XL2 and a Quad-Xeon monster editing station with 15kRPM SCSI Array, 2 GB of Rambus, and all kinds of goodies like a Hoontech DSP24 MkII and a Canopus MVR1000 R/T MPEG encoder(that I dont plan to use). I have some 24p footage I shot, and want to begin capturing it to edit in Premiere Pro 1.5. As of now...I have no hardware assisted video rendering..I soon plan on an RT.X100 Matrox system.

So basically my questions are these:

1. Must I use the Canon XL2 or its program to capture 24p while shooting and capturing or can I use a DSR-11(or similiar). I want to keep the head usage to recording only...not capture and playback.

2. Can Adobe capture 24p footage, and do you choose the Panasonic 24p preset?

3. For eventual television broadcast, do I use the 2:3 or 2:3:3:2 pull down?


Thanks again,


AJ

Barry Green October 31st, 2004 11:38 PM

1) any deck can play back 24P footage

2) Should be able to, and yes, but I'm not a Premiere Pro user so that's a guess

3) The question of which pulldown scheme to use isn't so much a decision of what it's going to be viewed on, but rather what it's going to be edited at. If editing in a 24P timeline, use 2:3:3:2. If editing in a 60i timeline, use 2:3.

For broadcast you will have to output it as 60i, which means that if you edit in a 24P timeline, you'll want to output as 2:3.

William LiPera November 2nd, 2004 01:26 PM

24p and dvds
 
So what is the best way to edit and encode 24p if the final destination is dvd for viewing on a progressive scan dvd player on a HDTV with component input?

Barry Green November 2nd, 2004 02:58 PM

DVD players are all standard-def, so don't even worry about high-def.

Use a program like Sony's Vegas that understands progressive-scan 24P footage. Vegas plus DVD Architect will give you a full pure 24P DVD, start to finish, just like Hollywood DVD's.

William LiPera November 2nd, 2004 06:07 PM

pure 24p dvd
 
What does a pure 24p dvd actually mean?

Barry Green November 2nd, 2004 06:17 PM

Well, what I mean by that is, the material is encoded on the disc as progressive-scan frames, rather than interlaced; and at the rate of 24 frames per second, rather than 60 fields per second.

Hollywood movies are encoded as 24P DVD's.

DVD players understand the 24P sequence and will automatically insert 3:2 pulldown when playing a 24P DVD onto an interlaced television. But if you're playing a 24P DVD on a device that supports 24P playback (such as a computer DVD player) it'll play back the original pure 24P frames, with no pulldown.

Encoding at 24P allows you to fit 20% more info on the disc, or to use a higher bitrate (lower compression ratio) to get higher-quality encoding.

William LiPera November 2nd, 2004 07:25 PM

24p dvd and HDTV
 
Will it play 24p without pulldown on a progressive scan dvd player playing on a widescreen hdtv with component input? Thanks. Just want to get this straight.

Barry Green November 2nd, 2004 08:31 PM

It is my understanding that it will, but I don't have that combination so I can't say for sure.

Joshua Starnes November 3rd, 2004 11:27 AM

Re: 24p dvd and HDTV
 
Will it play 24p without pulldown on a progressive scan dvd player playing on a widescreen hdtv with component input? Thanks. Just want to get this straight.

No, it won't, because there are no TVs that exist right now that will show a pure 24p image.

The TV will perform the pulldown in order to show a 24p image on a 30i screen (which is what all HDTVs are right now) and that is it.

There is no way to show a pure 24p image on a TV right now-it doesn't matter whether it is an HDTV, component input, progressive scan DVD player or not. You can see an approximation of it, but not the real thing.

One day there will be TVs that can show an actual 24p image, but they don't exist right now.

Marty Hudzik November 3rd, 2004 12:02 PM

I'm not trying to question you on this but I thought HDTV was progressive by nature? You know.....720P is one of the standards. Why would we be limited to interlaced. Also....there are televisions that are advertised as doing 3:2 puldown removal on the fly for better image quality. Why would it remove the 3:2 pulldown from the source file just to re-add it on the boob tube itself? It seems that adding this as a feature would be pointless if the display can't actually display the 24P image.

Anyone got some hard concrete facts on this? Because I always thought a progressive 24P dvd would play back at 24 FPS on a "qualified" HD monitor. Some may not but I think it is a feature that is available.

Joshua Starnes November 3rd, 2004 12:37 PM

They are progressive by nature, but they are progressive at 30p only (I realize now I mistyped in my previous answer). When the TV is reading the progressive DVD player, it is reading it at 30p, not 24p. However, that does not, to the naked eye, change the movement of something that originated in 24p.

There is no TV that will show a true 24p image at the moment.

Marty Hudzik November 3rd, 2004 12:56 PM

Well the whole thing seems rather stupid to me. Why advertise that your TV has 3:2 pulldown for higher image qulaity when it doesn't really do anything but add back the same extra frames/fields that it is supposedly removing?

On another note I read somewhere that it may actually show 60P instead. In other words the 3:2 puldown is not field based but just time based. IT would show the first frame for 3/60 of a second and the next for 2/60 and the repeat. So it is doing a 3:2 pulldown but shows each full progressive image the entire time. Make sense?

The 60P is based off of the 60hz of US power supply. I also read that if we could generate a 72HZ signal to refresh the monitor then rather than a 3:2 pulldown it could do a 3:3 puldown....if that is the right term. In that case it could show each progressive frame 3 times and then move onto the next for 3 and so on. Then every frame would be even, temporally speeking, and fit exactly 24 in each second. This is not that different from how movie houses actually show each frame twice. The eye can't perceive it and we just see an even, non juddering cadence.

William LiPera November 4th, 2004 10:50 AM

24p for dvd
 
Is there any real advantage to editing in 24p (rather than 2:3 pulldown 60i ) if the final product is dvd in a progressive scan dvd player for hdtv widescreen viewing. As far as I understand progressive scan dvd players output 30p after de-interlacing the footage.

Christopher Go November 4th, 2004 11:53 AM

ISO Rating for XL2 in 24P?
 
What is the XL2's ISO rating at 24P, 16:9, with 1/48 shutter?

Joshua Starnes November 4th, 2004 12:18 PM

Yes. It will enable your cuts to be more accurate. Also it will allow you to follow the timecode you recorded. It will also make a major difference on you sound editing.

Stay in 24p until its time to put it on a DVD. That will give you the best results.

Yi Fong Yu November 4th, 2004 01:35 PM

what's iso?

David Lach November 4th, 2004 01:48 PM

ISO is the film stock sensibility, formerly known as ASA. The equivalent in video is EI (exposure index).

I was planing to test every setting this week-end (every gain level).

I might post my results if nobody has done it yet.

Pretty simple to test, you shoot a flat lit 18% grey card in auto mode with the gain level of your choice, and find an ISO setting on your meter that will match the aperture chosen by the camera with the corresponding shutter speed.

William LiPera November 4th, 2004 02:10 PM

24p to dvd
 
In what way will the cuts be more accurate and how is the sound affected if with 2:3 pull down no frames are lost ? This particular issue has never been clearly explained, from what I can find. Thanks

David Lach November 4th, 2004 02:56 PM

The two major advantages I see of editing in 24p (assuming you will shoot 24p regardless) is less rendering time and less compression on your DVD.

Less rendering because you only render 24fps instead of 30. If you've done complicated effects in post before, you know how much of a time saver this will be.

Less compression on the DVD based on the same principle. You only put 24fps on the DVD and let the DVD player do the 3:2 pull down when played on the TV. That way, you need to compress 6 less frames per second, meaning there's more room the preserve the overall quality (24fps compressed over 4.7GB or 9.6GB instead of 30fps).

William LiPera November 4th, 2004 03:16 PM

24p for dvd
 
But if your project is less than an hour, can't you fix the amount of compression to a low rate, regardless of the frame rate, to yield the same quality?

David Lach November 4th, 2004 03:43 PM

Sure you can, if you have enough room regardless, it's not really a problem, and won't make a huge difference.

You will still need to render only 24fps instead of 30fps, so you save time with your NLE rendering no matter the time of your project.


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