DVX100e difference?

[Shai Levy]

>>> 50 interlace will look exactly like 25P. That's the point of interlace. As far as I know you don't see the upper field, then the lower, then the upper, then the lower 50 times per second, right! you have the illusion of 25 frame per seconds. So in PAL land that Panasonic is useless for people who won't transfer to film.
Philippe -->>>

philippe.... are you sure of that??? wouldn't a 25P have at least the "frame mode" effect (besides the true native progressive scan)?????
...you dont actualy "see fields" in a normal interlaced footage.. you just see the annoying rappid image that we try to escape when we go progressive

i somehow think that a 25P footage will look as good as (if not better then) a 24P on a regualar monitor... is there anyone who knows for sure??

shai

[Philippe Orlando]

"wouldn't a 25P have at least the "frame mode" effect (besides the true native progressive scan)?????"

>>>a 25P camera is what it is, a camera that takes entire frames, 25 of them every seconds. Yes. What's the problem here. I'm not saying anything agaisnt that.

I'm saying that a normal video cam PAl sampling 50i per seconds. On a PAL tv set DOES look like footage that was shot by a 25P.
I defy anybody to see the difference. NOW, if you were in NTSC land, you'd see the difference between something shot at 24P and broadcast on an NTSC TV


"you dont actualy "see fields" in a normal interlaced footage.. you just see the annoying rappid image that we try to escape when we go progressive"

>>>What! What are you talking about! the annoying rapid image that we try to escape.....?

So you're saying you see the fields ?

WHen Engineers developed PAL they chose 50 alternating fields per seconds because, amont other thing it' give the illusion of motion like a movie did. 25 is close enough to 24. There is not way yo can see the fields. NO WAY. You mean can you see the current in a bulb fluctuating 50 times per seconds? Can you? No, I 'd say for your eyes the filament is burning on all the time.
Think about it, if you were able to see the fields, 50 of them in one image of PAL footage you'd be able to see each 24 frame of a projected movie individualy. Can you? Do you see 24 individual frames when you watch one second of movie or do you see motion?

25P footage won't look better than 50i footage in PAL land. THe whole poing of 50i is to give the illusion of 25P. If 50i fields were not giving you the illusion of 25 full frame per seconds there would be no point. YOur eyes are not that good. Listen, I spent the first 30 years in my life in France where we use PAL and now I live in the US, I have two camera, a PAL and an NTSC, I'm used to the effect.

The advantage of 25P over 50i is that when you transfer to film there's not need to deinterlace, and so less chance of messing up by the transfer house. But again at the risk of being heavy, if all you do is watch footage on PAL land on a TV the 25P is useless since you already haver the illusion of 25p with the current 50i.

Philippe

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edited by Chris Hurd 07 Feb 2003

[Chris Hurd]

A reminder to keep the nature of this conversation on a friendly, mutually respectful basis. Any flaming will be deleted. See the FAQ for a better understanding of our forum policy.

There is indeed much confusion here. It should be understood that regardless of system (PAL vs. NTSC), there will be a noticeable difference in the video image between progressive and interlaced scanning.

50i does not appear the same as 25p, just as 60i does not appear the same as 30p. The difference in each may be discerned by anybody who has the opportunity to compare them.

No one will claim to be able to resolve the separate fields of an interlaced image. The optical illusion we know as "persistence of vision" insures this, and is the key to understanding how interlaced images work. However there may be some confusion in this conversation about what constitutes an interlaced field... they are not "upper and lower" (these are editing terms), but rather, odd lines and even. The first field consitutes all the odd lines of the image, the second field is all the even lines... basically two full-size but half-resolution images one after the other, alternating so fast (1/50th second for PAL, 1/60th second for NTSC) that you can't notice them, thanks to persistence of vision.

With progressive scan it's a bit different. The entire frame, not just half of it, is grabbed at once by the CCD. Instead of alternating half-pictures 50 or 60 times per second, with progressive scan now it's a full-size, full-resolution image at 25 or 30 frames per second. As Frank says, "a bit choppy" compared to interlace, precisely because of the difference in frame rate.

And most everybody can notice a difference between progressive and interlace, regardless of whether it's PAL or NTSC. The reason is due to a perceivable difference in temporal motion... the change in frame rate (from 50 or 60 down to 25 or 30) won't be resolved by the eye but rather felt by the mind. Am I saying it's in your head? Yes, to a degree. If you're used to watching NTSC at 60i, and then look at a PAL 50i image, the flicker is instantly noticeable, and then goes away... because the brain adjusts for the change. I saw this myself at the NAB convention, where Sony had an interesting comparison of identical video images displayed on different monitors at different frame rates... 60i, 50i, 30p, 25p etc. It all looked like video but each one felt a bit different... the motion judder is different in each, as is the degree of strobe... because each frame rate produces a different feeling of temporal motion in the brain. And no one of them is right or wrong, they're just different.

In short, there will be a perceivable difference between 50i and 25p. I have seen it -- or rather, I have felt it -- and you can too. 50i does not appear to be identical at all to 25p.

However, I would seriously doubt anyone's claim to perceive a difference between 25p and 24p (or for that matter, 25p and 26p, if there were such a thing). A one-frame-per-second difference would not be noticeable. a 5fps or 10fps difference is noticeable, though.

Lastly, the Panasonic AG-DVX100 is a superb camcorder even without the 24p feature and it is a serious tool for video production whether it's the PAL or NTSC version. The advice to "wait for Sony" is sadly misguided. If you spent your time waiting for the next new camera, then you'll never produce anything. In this day and age, if you have something to shoot, then NOW is always the best time to buy.

E-Gene Soh, I hope this helps. There is so much more to a "film look" than the frame rate; but that's another topic which is covered in our Film Look forum. Keep your questions coming!