|
This topic comprises 3 pages: 1 2 3
|
Author
|
Topic: Why Doesn't Video Look Like Film????
|
|
Brad Miller
Administrator
![](http://www.film-tech.com/ubbmembers/02a.jpg)
Posts: 17775
From: Plano, TX (36.2 miles NW of Rockwall)
Registered: May 99
|
posted 01-11-2002 03:39 AM
Ahhh, vidiots! ![](http://www.film-tech.com/ubb/smile.gif) Video doesn't look like film because it ISN'T film and it is very much so inferior to film for all of the reasons you mentioned. No offense to the guys over there, but anyone who thinks video does look like film is obviously an amateur videographer. As time passes and they gain more experience, they will understand the difference. Perhaps the comparison of Home Improvement (video) vs. Malcolm in the Middle (film) was made, they would get it.
| IP: Logged
|
|
|
|
|
Scott Norwood
Film God
![](http://www.film-tech.com/ubbmembers/30f.jpg)
Posts: 8146
From: Boston, MA. USA (1774.21 miles northeast of Dallas)
Registered: Jun 99
|
posted 01-11-2002 06:09 AM
A few quick points:- film has grain, videotape doesn't - film has a wider exposure latitude and thus is capable of capturing better shadow and highlight detail - different film stocks have different looks (e.g. compare Kodachrome with Vision 500T), whereas the CCDs (or tubes) in any given type of video camera all pretty much look alike (though different models also look different) - if they're talking about film as viewed on video, there's the issue of the transfer process, which allows for many types of image manipulation and color/exposure correction, etc. - stuff shot on film usually has a higher budget than stuff shot on video, which generally translates into stuff like a better DP, better lighting, better post-production work, etc. But, yeah, it all comes down to the fact that these are two completely different media. Asking "why doesn't film look like video" is a bit like asking "why don't oil paintings look like photographs."
| IP: Logged
|
|
Matt Close
Expert Film Handler
![](http://www.film-tech.com/ubbmembers/996.jpg)
Posts: 226
From: Hervey Bay, QLD, Australia
Registered: Sep 2001
|
posted 01-11-2002 06:47 AM
Joe, I believe it is just as your post on the DV site states ... film is 24 frame/s, and NTSC video is 60 fields/s. Video has that 'cheesy' look to it because of 'interlacing'. NTSC video is actually shown at 30 frames/s, but each frame is made up of two 'fields'. If you look at the make up of a tv picture in terms of 'lines', you can refer to them as 'odd' and 'even' lines... or 'odd field' and even 'field'. This was developed originally by some clever cookies to eliminate visible flicker on the screen.... and as a result, motion looks far smoother than film could ever produce. I read a thread on here the other day that queried why when panning accross a cinema screen, things seem to look 'jumpy' and 'hard to follow'. It is because of the frame rate of 24fps. [ At least, I think it is, isn't it? ]Now 30 frames a second doesn't seem a lot more, so why doesn't it happen on video? Well, as we have already said, video is not just 30 frames/s, but 60 'fields/s'. Each 'field' really represents a 'frame' made up of even or odd lines. If you were to look at one 'field', it would look like someone had closed venitian blinds over the camera, but of course when you display 60 alternating fields all together in one second, it looks like smooth motion. It is this use of 'interlaced' frames that gives video it's 'look'. Ever wondered why when you pause an older VCR, you get that blurred flicker between two images? ... It's because you are seeing two fields at onces, or two 'venitian blind' frames .... One odd, one even .... A 'film' look, on the other hand, is achieved with 'progressive' frames..... Now, before anybody jumps up and down, film is of course generally superior to video due to lenses, lighting, far higher resolution, better contrast, better colour depth, no colour bleeding ... etc , etc, etc.... but I believe the thing which really sets the 'looks' of the two apart is the progressive/interlaced difference. For those of you who follow the home entertainment scene, you may have noticed the more up-market DVD players these days featuring 'progressive frame output' on their list of specs..... Why? ... to get that 'film look' of course. The NTSC MPEG2 DVD standard supports not only 30 frames/s, but also 24 frames/s. So, in the transfer of a film to DVD, there is no telecine process required, therefore no interlacing at all, and when played on a 'progressive output' DVD, you get about as close as you can get to the way it was 'supposed' to look. It'll never compete with the real thing though! If you're inclined to play around with computers, get your hands on an 'interlaced' DVD (not a movie), pop it in to your DVD-ROM drive and watch it..... It will look different to the way it does on tv, because your DVD player software will 'de-interlace' it. (Computers can't display interlaced video) The motion doesn't look quite as smooth, and the picture doesn't seem as sharp. That's because you are seeing two 'fields' kinda 'blurred' together every 1/30th of a second. Pause it in a scene of high motion and you will see what I mean. So, when it comes to 'motion' , video leaves 'standard' film for dead .... But film kicks ass everywhere else. Why do they shoot more up-market tv shows on film? ... hmmmm .. I wonder ![](http://www.film-tech.com/ubb/wink.gif) I hope this all makes sense to everyone, and if I'm wrong ..... feel free to shoot me down in flames ... or is that 'frames'?
| IP: Logged
|
|
Ray Derrick
Master Film Handler
![](http://www.film-tech.com/ubbmembers/1001.jpg)
Posts: 310
From: Sydney, Australia
Registered: Sep 2001
|
posted 01-11-2002 08:10 AM
Re Joe's original post, many TV programs, particularly wildlife docos and the like, are shot on super 35 film. So you may ask why go to the expense and inconvenience of using film in the production of programs destined only for electronic media? The answer is that many producers prefer the "look" of film. Pictures from TV cameras tend to have stark contrast, hard edges and exaggerated colour whereas film tends to have a softer look and more realistic colour rendition. When film material is transferred to video in a telecine it does not lose this film "look".I suspect that when full digital production becomes common with feature movies, someone will come up with an elaborate digital filter process to recapture the "look" of film. Also ever noticed how an actor's makeup is much more obvious in a video production? Somehow a film camera has this knack of making makeup disappear. ------------------ Ray Derrick President Panalogic Corporation Pty Limited 44 Carrington Road Castle Hill NSW 2154 Australia Phone: 61 (0)2 9894 6655 Fax: 61 (0)2 9894 6935
| IP: Logged
|
|
Dave Macaulay
Film God
![](http://www.film-tech.com/ubbmembers/813.jpg)
Posts: 2321
From: Toronto, Canada
Registered: Apr 2001
|
posted 01-11-2002 08:32 AM
Matt: The frame vs field theory only works for acually moving images, yet video and film look different even when showing a still image. Motion artifacts can be manipulated in both formats by varying the actual exposure time per frame/field, essentially choosing between a "jerky" progression of very sharp images or a less jerky progression of images with motion blur. The perceptual effect is different but neither can really be called better. I agree normal video has less motion artifacts because of the 60 (or 50) images per second. Our minds somehow combine the 2 half-resolution images into a full resolution composite - much like combining the successive images to perceive motion. The progressive scan system was not enirely for flicker reasons - presenting 60 (or fewer) full frames a second would do that. Progressive scan saves RF bandwidth in transmission (not sure they cared about it then...) and halves the data rate simplifying everything in the chain. 60 fps was picked because much less and the picture is clearly perceived as flickering. Film gets away with 48 because it's not as bright and usually covers more of the visual field, but if you look at the picture with just the edge of your peripheral vision in a bright scene you will see definite flicker. Increasing the frame rate of film reduces the motion artifacts but both Showscan and Imax HD failed to prosper because the "problem" is so trivial that a solution has to be very low cost to bother with. People are just not bothered by the motion artifacts. A simulator ride with Showscan is more convincing that with 24fps film - but not overwhelmingly. Most people would be just as entertained without the 60fps "reality". So why does a still image look so different? With Showscan it looks different from a normal 24fps film - more like a slide than a movie, but still "different" from video. A film image seen at 1fps on a Kineton FP30ES with the shutter running at 24fps still looks like film although it is obviously a (relatively) "still" image rather than a movie of a motionless subject. Probably one could produce a comparison between HDTV and showscan that is almost indistinguishable: The biggest difference is in contrast range. Film has much more than video - 100:1 at least, video is around 40:1 (HDTV might be a bit better) - this can be masked for comparison by limiting the contrast on the film. Next is the color space. NTSC has a more limited color space than film because of the limits of phosphors - there are a limited number of phosphor colors compared to dyes for film. The choice made for NTSC has a smaller color gamut than normal color film. Again, the color space can be constrained on film along with its contrast range or dyes matching the phosphors could be used. So... if we make a showscan (60fps) film to show (rear projection I suppose) beside an HDTV monitor with 60fps sequential scan, they can (probably) look indistinguishable with any program ONLY if we cripple the film. I think this contrast & color difference is one big reason for the "video look", not the field/frame rate. The other big one is the way frames are presented, scanning lines onto phosphors that immediately start to fade out vs evenly illuminated images interrupted by the shutter might be a huge perceptual difference and explain why video-to-film doesn't look like video when projected. This is today. Video will progress to equal film and probably become better. DLP has a better potential contrast range, a less constrained color space, doesn't necessarily scan like a phosphor tube (I don't know how or at what rate the DMD presents pixels), and right now is effectively equal to film quality for showing animated subjects. Unless "regular" TV abandons the NTSC standards and gives up backward compatibility it will forever be inferior to film, and can probably never equal it with direct view CRT technology. Oh... to transfer film to video, regardless of the final format, there is always a telecine process. You can call it a film scanner but the process is the same.
| IP: Logged
|
|
Paul Mayer
Oh get out of it Melvin, before it pulls you under!
![](http://www.film-tech.com/ubbmembers/355b.jpg)
Posts: 3836
From: Albuquerque, NM
Registered: Feb 2000
|
posted 01-11-2002 03:51 PM
Let's see...Frame/Field Rate: Already been well discussed here. Resolution: It'll be quite a while before a practical video imager/display/storage medium can match 35mm (or even 16mm) in this regard. Dynamic Range: Scott already talked about this. Many film stocks have an exposure latitude of seven stops or so, which allows the photographer all kinds of room for creative lighting setups. Only the best EFP (Electronic Film Production) video cameras can approach that. Consequently, lighting for video is more concerned about limiting the contrast range, which can lead to less dynamic looking pictures. Over-Exposure: Film fails gracefully, even beautifully here. Video ends up looking harsh here due to the action of white clip circuits. Modern-day cameras do have a "soft" clip feature to try to reduce this effect, but generally they are difficult to align (it's hard enough for most guys to get a camera to track grey-scale from 5-95 IRE as it is, let alone the separate controls for that last 95-100). Response Curve: Beyond just basic gamma, the curves are very different. Film has D Log e response to light--video does not, although the latest Sony EFP cameras do have the ability to store DSP settings (the knee and toe points on the curve) which allow the camera to mimic the look of several popular motion picture film stocks. Aperture Effect/Detail Enhancement/Noise Coring: All of these are factors that must be dealt with in a native video image. Film (other than managing grain (noise) issues) does not. Video edges, even the best of them, do not have the "effortless edge" look of film. Lenses: Not directly a film vs. video thing but go along with me here for a bit Even HD video is still pretty low in resolution compared to film. This means the lenses used for video can get away with things (like higher amounts of chromatic aberation or focus tracking error) that would be unacceptable on film. Prime film lenses are fixed focal-length, and film zoom lenses have relatively short zoom ratios (not many over 10:1), all to produce noticably sharper looking pictures with less lens flare. In video, the differences in the sharpness of fixed primes and good zooms are lost at the imager. So you hardly see fixed lenses used in video at all; instead you see relatively long zoom ratios, e.g. 18:1 for handhelds, 32:1 for studio cameras, up to 85:1 (!) for sports. Zoom lenses, having more elements within them, have more flare problems to contend with, and this shows up in the pictures. Differences in lenses also lead to differences in camera technique--i.e. film prefers fixed lenses so camera moves are used more often than zooms; video prefers zoom lenses so zooms are used more than camera moves. This area too is beginning to change with the latest HD EFP cameras like the Sony/Panavision being used on SWII which uses film lenses and is configured to work like a film camera (i.e. tape measuring the focus and use of a 1st AC/focus puller). BTW at one of the SMPTE Hollywood Section meetings it was mentioned that some wag thought the new camera should be called a PanaSony, a name that didn't go over real well with either Sony or Panasonic... ![](http://www.film-tech.com/ubb/biggrin.gif) I imagine that these film vs. video differences will get smaller over time. Cheers! Paul
| IP: Logged
|
|
Ray Derrick
Master Film Handler
![](http://www.film-tech.com/ubbmembers/1001.jpg)
Posts: 310
From: Sydney, Australia
Registered: Sep 2001
|
posted 01-11-2002 06:01 PM
MattYour frame vs field theory is good but if it were correct, then surely a film transferred to video would still have flicker on a pan. Doubling the effective "reproduce" frame rate of a motion picture already "recorded" does not result in the interpolation of new frames between the existing frames. This is not some DSP process where software can work out where the in-between image should be to smooth out the motion. The two video fields still reproduce the same static frame of film, and when the next frame comes along, it jumps to the left or right, just as it would from a projector. I have only ever noticed pan flicker in movie theatres, never on video. Surely this has more to do with the imperfect nature of film projectors than the frame rate. Another point to consider in all of this, is that film is shot using mechanical apparatus. The film must be pulled down and held motionless for the duration of the exposure of each frame and likewise during projection. Anything physical has mass and when it moves has momentum, so stopping it absolutely dead and in exactly the same spot every time is almost impossible. So there must always be some degree of vertical and horizontal jitter (due to imperfect cameras, processing and projectors) which will affect the look of the image. By contrast, video does not rely on anything mechanical and is thus always absolutely rock solid, both vertically and horizontally. ------------------ Ray Derrick President Panalogic Corporation Pty Limited 44 Carrington Road Castle Hill NSW 2154 Australia Phone: 61 (0)2 9894 6655 Fax: 61 (0)2 9894 6935
| IP: Logged
|
|
|
|
Paul Mayer
Oh get out of it Melvin, before it pulls you under!
![](http://www.film-tech.com/ubbmembers/355b.jpg)
Posts: 3836
From: Albuquerque, NM
Registered: Feb 2000
|
posted 01-11-2002 07:42 PM
Regarding Ray's notion about pan flicker and frame rate vs. the imperfect nature of projectors, I think that frame rate may actually be more of a factor. True, there's not much difference between 24 and 30 fps, but it certainly is quite noticable on a big screen. Film at 30 fps (29.97 stuff or ToddAO stuff) definitely has that "Showscan" look to it. Enough so that I think most people wouldn't be able to discern the difference between 30 and 60 fps. But there sure is a noticable difference between 24 and 30 fps...Also, shutter angle has a lot to do with perceived pan flicker. Before chip imagers, video cameras didn't have shutters and therefore created enough motion blurring on fast moving scenes to largely negate visible pan flicker. On a shutter camera you can create more pan flicker (I think the ASC calls it judder) by switching to faster shutter speed (lower shutter angle). The rule of thumb in the ASC Cinematographer Handbook says anything faster than one-half the reciprocal of the frame rate (e.g. 1/50 sec at 24 fps, 1/60 sec at 30 fps) will increase this effect. This also explains Joe's example of a typical SF movie star field. If motion blurring isn't added on the animation stand (or in the CG these days) the judder is more pronounced. Same thing in stop-motion animation--compare Nightmare Before Christmas to almost anything done before it to see how motion blurring improves the apparent smoothness of the animation. I suppose a wee bit of image weave is a part of the "film look" too. I've noticed in various DLP screenings that things like title or rating cards look like electronic stills, due to the weave being so tightly controlled both mechanically and electronically during transfer. Hmmm. Regarding Barbarella, I noticed the same effect in Tomb Raider. Need to go back and stretch those blacks a bit so we can do a more thorough analysis of this phenomenom... ![](http://www.film-tech.com/ubb/biggrin.gif) Cheers! Paul SMPTE Hollywood Section Unemployed Mercenary film/video projectionist/engineer "When the money runs out, so does I."
| IP: Logged
|
|
|
|
All times are Central (GMT -6:00)
|
This topic comprises 3 pages: 1 2 3
|
Powered by Infopop Corporation
UBB.classicTM
6.3.1.2
The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion
and agrees to release the authors from any and all liability.
|