The market for long format films captured on digital video is emerging rapidly. From Mini DV to 24p HD, an affordable alternative to traditional film capture is empowering a new generation of filmmakers. Cine-Byte is working to provide affordable solutions for this market while generating the highest quality film output available.
When shooting Digital Video intended for a 35mm film finish, there are a number of issues to address. When selecting your digital video format, you must take into consideration all the requirements for transferring to 35mm. What are the framing issues? Will the images need color correction? Do video frame rates matter and why? Which formats produce the best images? Which digital format is best for my production? Below we try to address some of these individual topics, and give a better understanding of the Digital Video to Film process.
Video
Frame Rates
Cine-Byte
uses a proprietary software algorithm to convert field-based video to 24 fps
non-interlaced frames. When shooting digital video for a film finish, frame
rate conversion is arguably the single most important issue. NTSC video runs
at 60 (59.94) interlaced fields per second, and 35mm motion picture film runs
at 24 frames per second. PAL video frames have a higher pixel resolution,
but they are also interlaced, running at 50 fields per second. To compensate
for the difference in frame rates, field-based video must be time-compressed
down to 24fps. If you have the budget, 24P High Def video running at 24 fps
non-interlaced, is the ideal solution. But for those working with field-based
video, Cine-Byte's software solution will convert PAL or NTSC to 24fps non-interlaced
with no motion artifacting.
Framing
for Film
The
two standard motion picture projection aspect ratios for North America are
1:1.85 and 1:2.35 (flat and scope). Currently the standard for broadcast video
is 1:1.33 (4x3). When recording video material for output to film, image cropping
for theatrical projection must taken into consideration as illustrated below.
Framing for Film on a 4x3 Aspect Ratio video frame:
Digital Video Camera Resolutions
| HD |
PAL |
NTSC |
| 1920x1080 |
720x576 |
720x480 |
Digital
Video Exposure
Digital
video does not have the same exposure range as 35mm feature film. Film sees
far more detail in shadow areas, and also holds more detail in over-exposed
areas. Video tends to get very muddy in the shadows, or blow out and clip
in the highlights. To avoid the video/electronic look, you have to approach
lighting a little differently.
When shooting video for film, it is important to treat your digital images as if they were camera negative. In other words, don't shoot your digital video as if it were an answer print. A slight overexposure of the shadow detail is preferred, giving you the ability to darken the image in post-production if needed. In highlight areas, you must be cautious of not overexposing bright areas, as video clipping will occur and all detail will be lost. Pre-production testing of lighting scenarios, followed by video to film pipeline tests are highly recommended before you go into production.
Digital
Color Correction
At
some point your final Digital Master will have to be color corrected for film
projection. Most of these corrections are simple color matching from scene
to scene for consistency. We believe the best option for color correction
is to avoid traditional film timing, and have your video master digitally
color corrected. By correcting the digital tape (or files), you will have
a color corrected master ready for broadcast, and from that master a digital
negative will be created that will need only minor timing adjustments for
release printing.
Digital Video Formats
The digital format you choose for your production will be based on a number of factors; production budget, locations, crew experience, production needs, etc. Listed below is a sample of some of the Digital Video Formats available, and their advantages and disadvantages as they pertain to producing a quality 35mm film negative.
High Definition (HD) Formats
HDCam 24P The 24 frame progressive HD Camera is the ideal digital video format for a feature film finish. The frame rate translates directly to film frames, and the resolution actually exceeds the digital standard 2k-academy resolution. The only drawback (aside from cost) is the high compression rate of HDCam (7-10:1). This can result in video artifacting when projected on the big screen. To avoid this, extra care must be taken during production to ensure a properly exposed digital video.
Alternate HDCam Formats (1080i, 1035i, 1080p, etc) The other HD formats (not including 24p/25p) are also excellent for film projects, in terms of resolution and aspect ratio. Unfortunately, these HD formats capture at 30 fps and/or use interlaced images, introducing quality problems. (See Frame Rates/Interlaced sections above).
HD D5 Although this is not an HD camera format, the HD D5 from Panasonic offers a much better compression rate (4:1) than Sony's HD Cam (7-10:1). HD D5, running at 24P, is an excellent storage medium for HD film material, particularly images originating on film or in a computer generated environment.
HD D6 Not an HD capture format, but definitely top of the line in terms of HD storage. D6 is an uncompressed, real time HD tape format. This makes D6 the ideal solution for storing images originating on film, or coming from a computer generated environment. Unfortunately, the D6 is large, bulky, and very expensive (!).
Digital BetaCam
PAL DigiBeta This is an excellent option for digital video to film. Pal resolution is superior to NTSC, and the frame rate (25fps) is very close to film. A camera with a 16x9 option is recommended. DBeta also has a very good compression rate of 2:1 to help avoid video artifacting.
NTSC DigiBeta Resolution and compression rate (2:1) are acceptable for film output. A camera with a 16x9 option is recommended.
DV Formats
DV, DV Cam, DVC Pro All the DV formats are reasonable video to film options if used properly. Resolution is fairly standard between formats (NTSC 720x480, PAL 720x576). Again, PAL is preferred to NTSC due to the slightly higher resolution and frame rate advantages. Also, a camera with true 16x9 (anamorphic) capture is highly recommended. All DV formats use 5:1 compression.
Filmmakers must be careful in DV production to avoid corruption of images during exposure. Over-sharpening, underexposure in shadow areas, and overexposure in highlights are common problems, but all avoidable. A camera with maximum control over these features would be preferred. Overall, the DV formats are an inexpensive digital video option that can translate well to film.
| Format |
Resolution |
Compression |
Frame
Rate |
Aspect
Ratio |
Interlaced/Progressive |
| 24P
HDCam |
1920x1080 |
7-10:1 |
24
fps |
16x9 |
Progressive |
| 1080i
HDCam |
1920x1080 |
7-10:1 |
24
fps |
16x9 |
Interlaced |
| HD
D5** |
1920x1080 |
4:1 |
24/30
fps |
16x9 |
Interlaced/Progressive |
| HD
D6** |
1920x1080 |
None |
24/30
fps |
16x9 |
Interlaced/Progressive |
| PAL
DBeta |
720x576 |
2:1 |
25
fps |
4x3
(16x9 options) |
Interlaced |
| NTSC
DBeta |
720x486 |
2:1 |
30
fps |
4x3
(16x9 options) |
Interlaced |
| PAL
DV |
720x576 |
5:1 |
25
fps |
4x3
(16x9 options) |
Interlaced
(Prog. options) |
| NTSC
DV |
720x480 |
5:1 |
30
fps |
4x3
(16x9 options) |
Interlaced
|
** not a camera format
The above example shows theatre projection grids applied to a 4x3 NTSC image. For film framing, 1.85 results in a better quality blow-up because it uses more of the image area, and therefore more resolution. Although 2.35 is still an option, when projected it will use fewer pixels to cover a huge screen area (possibly a 70 ft screen!).
Framing for Film on a 16x9 Aspect Ratio video frame:
