HD newbe here, so beware! ;-)

My Z7U, when set for 24P, even the slowest pan is jerky. Any movement, even with the camera stationary, a person walking slowly looks jerky. Perfectly smooth at 1080i.

I can't believe what I'm seeing would be acceptable--film doesn't look like this to me.

What am I missing? A setting or . . . ?

Thanks!

It may be the on-camera display. Try connecting it to a monitor. If the problem persists, maybe you could post a clip.

24p is jerky, even with the best film cameras. That's why you see all those dolly tracks on any film shoot.

When you shoot 24p you have to really watch your movement and rarely zoom if at all. None of this is unique to the Z7. That's just the way it is with any 24p.

The reason is because of the way our brains interpret image sequences. If we see too much movement between 2 frames our brain sees to separate images, where as if you have a sequence of oh, I don't know, say 24 images every second :), where it the difference between each frame is within acceptable limits then your brain fills in the gaps and makes the motion smooth ( same thing with 30P and 60i but it's less problematic because there are more frames there so the difference between each one is less and your brain is much less likely to discern each frame separately. ( wow that was a run on sentence :P ).

I'd highly suggest you do a little studying on filming techniques if you want to continue to use 24p as it has some rules ( well, maybe not so much rules as ... guidelines ) such as not panning something across the screen faster than 7 seconds (depending on screen aspect ratio or SAR for short) among others.

24p is actually just a standard that was arrived at because it was the cheapest frame rate that most motion appeared smooth at.

Anywho, just a little FYI there I guess.

Dave

It is due to the 2-3 pull down.
Z7U records the 24p image over 60i through the 2-3 pull down process.

FYI, film flashes twice a frame. It means there are 48 flashes per second.
It looks smooth compared to the digital 24p.

It is due to the 2-3 pull down.
Z7U records the 24p image over 60i through the 2-3 pull down process.

FYI, film flashes twice a frame. It means there are 48 flashes per second.
It looks smooth compared to the digital 24p.

Thanks, I didn't know that :)

Always happy when I learn something new, any other knowledge tidbits you care to share ? :)

dave

This info is VERY helpful, but leads to more questions.

The jerkyness I'm seeing seems like makes 24p unusable. Even with my Z7 is on a tripod as is not panning or moving at all, a person on the screen moves his arm to pick up a drink of water, looks annoyingly jerky. How can film filmmakers be excited about 24p video cams for making movies? It looks awful to me. I've tried with a small monitor and my 52 inch 1080P LCD, the jerkiness is bad. And, these days the fashion is that something has to be moving at all times--preferably the cam is always panning or something.

If film is 24 frames but is delivered to the screen 48 times per second and 24P video is delivered only 24 times, how can it have the famous "film look" I keep reading about?

[I've read about pull-down many times--which I could understand it!]

As I read what I just wrote it sound like I'm ranting or something! Don't mean to be--I've read so much about how great it is to have 24p that I'm thinking I must be missing something.

Thanks!

Is your shutter speed set correctly? Make sure it is set to 48 and not 60. This will help. Secondly, as mentioned before, when shooting 24p your movements a slow and smooth.

For action you can shoot at an even higher shutter speed, but the higher your shutter, the more light you will need.

About pulldown: http://en.wikipedia.org/wiki/Telecine#2:3_pulldown

In my mind 24P is a FAD. There was a good reason to shoot this way in video when the intent was to transfer to film for a film festival etc. But the technique has to be film technique not the way video is shot. Shoot still closeups ( with the backround out of focus etc), no pans, very slow zooms etc. As mentioned in an earlier post 24 frames per second was chosen as the optimum cost for film stock costs for distribution and sound quality for optical sound tracks. You will notice that a lot of action shots in films are in slow motion, they are shot at high frames rates to stop the stuttering!!!!! There are some other technical issues in that a film projector will normally have 3 blades on the shutter and thus flicker the image 3 times for each frame ( 72 frames a second as far as our eyes are concerned, some even have 5 blades) So our eyes are satisfied from a flicker rate but the images are still only shot at 24fps which is really too low for any sort of rapid movement. The financial issues of smooth motion and high sound quality are irrelevant with modern technology but the film techniques are still valid for creating the emotional effect. We just do not need the slow frame rate in my opinion. I am appalled by the stuttering of background in a lot of TV programs these days obviously shot in 24p with little regard for the poor image they are producing.
Just keep in mind that most of the film techniques of shallow depth of field, dolly tracking shots, high contrast images etc are used to disguise the inadequacy of shooting at 24fps. You can still use these techniques for effect but really don't need to use 24P and risk all the stuttering.

Ron Evans

D.J. & Ron THANKS! and yes, I'm yelling.

Very helpful and at my tech level! Really helps.

D.J. & Ron THANKS! and yes, I'm yelling.

Very helpful and at my tech level! Really helps.
So Jaums, what WAS the shutter speed you were using before on 24p mode? Was it 1/60th sec? Like DJ said, try using 1/48th sec.

Also, i believe there are 2 different 24p modes on the Z7.
Kenny agrees with me... :
http://www.dvinfo.net/conf/showpost.php?p=832433&postcount=57

Try both of them - theyre different. Refer to the manual. Let us know results. thanks.

In my mind 24P is a FAD. There was a good reason to shoot this way in video when the intent was to transfer to film for a film festival etc.Well I don't think it's a fad so much as it is just simply overused in situations where it shouldn't be. Use the right tool (in this case, frame rate) for the right job... 24P has its applications but it certainly ain't meant for everything. It's a great thing to have but it's been somewhat over-marketed.

Just tried 24 & 24A [24A = Phase of the 60i conversion is reset each time recording starts].

As far as my eye is concerned, 24 is jerky when you do even a very slow pan on a crane or the actor moves, unless the shutter is so high [1200] that it looks like a bad horror movie on the dark side of the moon, which has been invaded by black worms.

From what I'm reading here and my experiments, seems to me 24 may be useful if you are transferring to film, otherwise, don't use it.

*****FYI, film flashes twice a frame. It means there are 48 flashes per second.
It looks smooth compared to the digital 24p.[/QUOTE]****

Film operates at 24 frames per second, as far as frames goes. The film camera shutter rotates 48 times per second, that is true, but only 24 frames are being recorded as other 24 rotations are there for the film to be transport to the position for the next frame to be exposed. Film in film cameras does not flows through the camera continuously but intermittently: it has to stop for a short period for the frame to be recorded onto the tape. And due to persistence of our eyes that can not detect frequencies faster then 24 cycles it has been decided for purely economical (saving the tape) reasons to select the slowest non-detectable frequency for the rate of the film frames.

Nevertheless, 24p should not be jerky at any rate, jerkiness indicates that there is a problem in encoding - decoding system of the camcorder, I would say without actually seeing the footage and the camcorder/NLE sysyem setup.

Our eyes definitely see 24 fps as 24 individual images. To fool us into thinking it is moving image they need to be flashed at leased twice as fast ( 48 times a second or two times for each frame). This is marginal for a lot of people and as such a lot of projectors have 3 or 5 blades on the shutter to flash the images 3 or 5 times each, raising the flash rate to a rate that our eyes perceive as motion( my own projectors have 3 blades so even at silent Super8 rate of 18fps they flash at 54 flashes per second). For instance the TV in UK refreshes at 50hz and in North America at 60hz, that means images are flashed at the viewer that many times. When I lived in the UK I didn't see the flickering but since living in Canada for a long time every time I go back to visit it takes me almost a week before the flicker in the TV's is less noticable. So 50 frames a second in my mind is very marginal. Most films one sees from a projector are likely 72 flashes a second or more. The image thus doesn't flicker but any movement on the screen is still only at 24fps which is inadequate for any fast movement especially across the screen sometimes call judder to distinguish from the flicker rate. There are lots of books on film technique to mask this effect and these techniques are what create the film look not really 24fps judder which in my mind is a defect to cover up!!!! The other issue with shooting 24p video is playback. One needs a screen with a refresh rate a multiple of 24 so that there isn't a conflict in playback rate. Unless one has a 120hz LCD for instance there will be conflict that needs to be adjusted with pulldown of some form that could make the image motion worse!!!! OF course this doesn't apply if the purpose was to shoot on video( cheaper than film) and transfer to film for projection. Other than that 25P for Europe/PAl countries and 30P for North America would be a much better choice for video for progressive capture if one really needs to have such a slow frame rate. Personally I would like to move to 60P to have really smooth motion.

Ron Evans

If your interlaced camcorder is using a pseudo 24p method of recording, then you might need to deinterlace with software like JES_Deinterlacer. Once dienterlaced, you can then edit the files as 24p in your NLE of choice.

Check this video: http://www.vimeo.com/727203

It was shot in 24p (Canon's version), deinterlaced, then edited on a 24p timeline in FCP.

There is not much panning, but the movement looks smooth. You can also view this video: http://www.vimeo.com/697638. Looks pretty smooth.

You can also try shooting in 30p for less judder, but 60p is the schnizzle when it comes to smooth progressive shooting. Otherwise, just shoot interlaced.

Yeah, the "film look" is sooooo 20th century. I prefer the "video" look.

30p is also good in that you can mix 60i and 30p without worry.

There are basically two problems with 30p:

1/ It doesn't convert to 24p for film release well.
2/ it doesn't convert to PAL well.

Most PAL DVD players play back 60i or 30p just fine, but if you are interested in broadcast in a PAL country, you shouldn't shoot at 30p.

So what do you recommend for shooting weddings? 24p or 30p?

If your interlaced camcorder is using a pseudo 24p method of recording, then you might need to deinterlace with software like JES_Deinterlacer. Once dienterlaced, you can then edit the files as 24p in your NLE of choice.

Check this video: http://www.vimeo.com/727203

It was shot in 24p (Canon's version), deinterlaced, then edited on a 24p timeline in FCP.

There is not much panning, but the movement looks smooth. You can also view this video: http://www.vimeo.com/697638. Looks pretty smooth.

You can also try shooting in 30p for less judder, but 60p is the schnizzle when it comes to smooth progressive shooting. Otherwise, just shoot interlaced.

Yeah, the "film look" is sooooo 20th century. I prefer the "video" look.


John,

What program did you use to convert/embed that video with? I really like the interface. I've been using a cheap $35 program I got off the web, but I'd like something better.

Thanks,

Chad

JES Deinterlacer for Mac. SAved to photo jped. Edited on a 24p FCP timeline.

It's a great thing to have but it's been somewhat over-marketed.

That's like saying "film" or "video" or "color" is over-marketed.

People have been making and watching 24 fps films for nearly 100 years. I hardly think it's a "feature" or "option". For many motion image creators, it's a requirement to tell stories with moving pictures. There is big difference between "great" and "requirement".

60 (50) fps has its place for situations that require it (and maybe 120 fps in the future) but as of right now, the use of 30 fps and faster frame rates for narrative, documentary etc. is decreasing not increasing due to the availiability of low cost 24 fps production. I've noticed a real decrease in interlaced production on low-end docs.

The HV20 is the shining example of this.

Per this thread, if you have not shot 24p before, I highly recommend going to see a film in the theater that you are not interested in and just watch motion, camera moves. Then hopefully watch the same movie on a TV with pulldown etc.

Learning to develop an intuitive sense of bad panning, tilting, zooming speeds is important as is knowing how to follow a subject in a frame so that the artifacts of 24p are not an issue. Don't forget that with 1/48th shutter, certain fast moves can work well as well - it's those intermediate pan and title speeds that can get you in trouble.

ASC guidebooks etc. have some good info on precisely measuring this for various formats.

It was shot in 24p (Canon's version), deinterlaced, then edited on a 24p timeline in FCP.



That makes no sense. If it was shot 24p, there is nothing to de-interlaced. The
"p" stands for progressive. A deinterlaced filter with probably do nothing or soften the video and perhaps do something weird to the pull-down.


Yeah, the "film look" is sooooo 20th century. I prefer the "video" look.

You should know I started a very long thread here years ago talking about "film look" vs. "professional" look.

So, you need to define what you mean by "film look" - frame rate, color rendition, latitude, resolution, grain, lighting, camera work, production value or other.

These are actual all separate items and cannot be lumped together. Of course, my argument in the old thread was frame rate is the most important aesthetic factor in determining "look".

i was just reading this out of curiousity to see how this ended and felt i had to butt in for a sec. sorry.

Stephen i think John mean't he removed the 3:2 pulldown out of the 60i footage. because the Canon HV20 records 24p onto a 60i timeline with a 3:2 pulldown. correct? so i imagine by saying he deinterlaced was the same as saying he removed the 3:2 pulldown. then making it truly 24 progressive.

I wonder how much digital projection will change the aesthetics regarding frame rate on motion pictures...

I think 60p with 1/120 shutter looks way cooler and hyper, better suited for a crazy action movie than 24p, that otherwise may work very well for a slow paced drama.

24p was born as technical constraint and professionals made a good use of a bad thing. Maybe in the soon future new professionals can make good use of new elements.

Just like we choose what aperture to use, which angle to frame from or how to light the scene, we'll choose the frame rate of our movie instead of being stuck with only one option.

Well, unlike most opinions in this board, I don't view 24p as a simple fad. Allow me to argument my view.

I am well aware that the 24 frame per second cadence was established in the early days of the movie industry as the "minimum common denominator" between movement fluidity and film economy. It's the slowest FPS ratio that allows for a fluid perception of motion, thus allowing filmmakers of the day to save miles and miles of film.

Nevertheless, we have grown accustomed to associate that very 24FPS cadence with film narrative. For over a century the 24fps has become a staple of how we understand storytelling in movies. Just to prove it, compare any scene from a Hollywood movie (shot in 35 mm film at 24 FPS) with a similar scene from a soap opera (shot on interlaced NTSC at 29.97 FPS). Your perception of those different scenes is very different.

The 24 FPS film scene is understood as narrative, part of a story, and even "expensive" if shot well. The 29.97 interlace scene is subconsciously perceived as "fake", a "live feed" and even "cheaper" in certain circumstances.

Those perceptions have nothing to do with the quality of the images, but what we have grown used to. This is less related to the specific technology we use, but rather the industry conventions that have been used for over a century. For many decades we have seen movies in 24 FPS film, and television on 29.97 interlaced. Our brains have been accustomed to this language. If Hollywood had adopted 30FPS instead, our association would have been different. In short, the cadence of movies has become a part of the narrative itself, a part of the aesthetics of film storytelling.

One of my film school teachers said that the 24 FPS motion looks and feels different, as it somehow resembles the "motion of dreams" in our collective subconscious. I really like that analogy.

I have shot on film (mostly 16mm, but some 35mm), NTSC video, and now HD. From my personal experience, I get a much more consistent look and feel for my narrative productions when I use 24p, because it replicates that 24 FPS cadence we so strongly associate with movies. If I shoot the same in interlaced NTSC, the perception of the same material is automatically understood as something else (news report, live feed), but not a narrative piece.
The same goes the other way around. If I shoot material for a news report in 24p, it automatically loses its perception of "live event" or sense of immediacy. It feels like something belonging to a story of fiction, not reality.

I am well aware of how quirky and cumbersome the 24p video workflow can be, especially with some HD formats. Still, I wouldn't use any other frame rate for a narrative production, even if it's not intended to be transferred to film.

Just my two cents.

Although I really dislike 24p I see your point of view. The problem I have is that I do not mind watching film in a cinema that was shot on film with film technique and then projected properly by a professional projector that is likely to flicker at 72hz or greater. The issue I have is 24p on video, shot with poor technique( like one would shoot interlace video with too much pan movement etc) then somehow transposed into a 60i interlace stream for broadcast after being encoded for transmission down a cable is awful!!! Most progressives displays do not deal with 24p correctly so even coming from a DVD player that correctly delivers 24p, the original 24p image is corrupted into a juddering mess by various scaling,pulldown and interpolating circuits. Until there are displays that correctly emulate a film projector and a delivery mechanism is in place to correctly deliver that stream I for one will dislike 24p intensely because it is making my TV viewing terrible. Done in this fashion I believe it is a fad for people who want to be part of the film image but are not prepared to follow through with all the implications of this trend. If you shoot for broadcast television that will be distributed at 60i then shoot that way.

Ron Evans

Ron has presented a good information about 24p:

1) 24p was the frame-rate that allowed the minimum amount of film to be used that moved film with an optical track thru the sound head at a fast enough speed to allow frequencies up to 10kHz to be recorded.

2) A film frame is flashed on the screen because there must be time for the claw to yank another frame into the gate.

3) Humans will see BRIGHTNESS FLICKER unless the flashes occur AT LEAST 48Hz. Therefore, the same frame is flashed at least twice. Hence a 2 bladed shutter. This has NOTHING to do with creating smooth motion. Motion is created by the frame-rate which can be as low as 16 fps -- in fact, modern silent pix use 18 fps.

4) "flicker fusion frequency" is a function of brightness. 48Hz is the minimum. As projector's got brighter lamps, the increased brightness raised the FFF as so people saw flicker -- especially in bright skies. This is very EZ to see in PAL with TVs that display at 50Hz. So, 3 or 4 bladed shutters were used to raise the PRESENTATION rate to 72Hz or 96Hz. (Modern PAL TVs use a 100Hz presentation rate.) Again, this has nothing to do with creating motion.

5) HOWEVER -- it turns out that the presentation-rate can create "Foreground eye-tracking strobing." This is an eye-brain experience that is at its worst when the PRESENTATION rate is 2X the frame-rate.

The eye follows moving objects. It calculates the rate of motion so it EXPECTS the object will be in a certain positions. But, when the second flash of the SAME image occurs -- the eye has only moved half the distance to where it expects the new position should be. When the eye-brain sees 2 of the same objects slightly apart, you see strobing.

Guess what -- when 30p is displayed -- each image is PRESENTED twice. So shooting 30p or 25p -- you may be unhappy with the results.

6) With 60p HDTVs, 24p is presented WITH 3-2 pulldown. YES -- you do NOT see 24p!!!

The only way you'll ever see 24p at home is with a display that runs at 72Hz, 96Hz, or 120Hz!!! (Plus, a 24p connection from a BD player and a disc burned at 24p.)

7) Why then, shoot 24p? TO TRANSFER TO FILM!

8) But what if I want my video to look "less like video and more like film?" The simplest way is to use 25p or 30p. But, you'll need to know the rules of shooting low temporal rate media to minimize Foreground Strobing.

9) But I WANT 24p! OK -- you have two recording options. Pure 24p -- either 720p24 to tape or non-tape -- or 1080p24 to non-tape (except for the Canon XL-H1). If you shoot tape, you get 24p with 3-2 pulldown yielding 60i.

10) If you shoot 1080p24/60i -- you'll need to remove pulldown before editing in a 24p Timeline. But wait you say -- if I'm always going to see 24p with pulldown on my display, why do I need to remove pulldown before editing. Because if you don't -- when you edit you'll BREAK and MIX the 3-2 cadence.