This issue, Playback is launching a new section which takes a look behind the camera, devoted entirely to the ins and outs of cinematography.

In the first installment, mark collings, a Toronto-based technical consultant who has worked in marketing and sales in the production and post-production sectors, offers tips on camera and lighting technique and proofing when shooting on dtv.

We welcome suggestions from our readers as to topics they would like to see explored in upcoming issues.

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Camera techniques

the following questions were asked of dops who shoot both film and tape.

Q: How are color adjustments made during production when shooting digital tape?

One of these methods can be employed

a) Use a paint box (with remote control panel) to adjust color. A vectorscope (and waveform monitor) is required to do this.

b) Use a setup card. This is a card with an imbedded computer chip that stores camera settings.

The card is programmable. Preprogrammed cards are available for different looks (e.g.: cards that match the look of various film stocks or customized settings for various shooting environments).

Check to make sure the camera is equipped to use a setup card.

c) A good component digital color monitor is used during shooting as reference for contrast and color saturation. Experience has shown that what you see is what you get in video. For film dops, using a monitor during shooting is not something new as video assist is commonly used to check performances in film shoots.

Using a good component digital monitor as reference can eliminate the need for color correction in post-production latter on, with the attendant cost. Image enhancements are done when required in post.

It is important to note these are aesthetic judgments and not technical. A dop has a video technician to ensure the recording is okay, as technical parameters can be pushed and common rules for television shooting can be ignored.

It is important to have a video technician set up the camera: some color correction put off to tape-to-tape session in post.

In commercial shoots, the opinion of clients on set dictates changes to the image look (contrast, color saturation), therefore color is often adjusted during the shoot.

If image enlargement may be needed later, this will be addressed during shoot because there is a limit in enlarging video images (max 20%), where 35mm can be blown up larger.

Q: Video images, especially hdtv, are very sharp. What considerations, if any, are taken into account to reduce image sharpness for a ‘film look’? Can this done with filters on the camera?

hdtv compares in sharpness to 35mm, so sharpness is not an issue.

What affects image quality in video is ntsc artifacts. In ntsc the edges of images are enhanced by black lines. This creates a look that is harsher and less subtle than that of 35mm film.

hdtv uses a more subtle image enhancement technology that eliminates ntsc artifacts. For hdtv, less filtration is better. Use half the value of any filter used in film or Digital Betacam shooting.

Diffusion is used all the time to soften the video image, usually a black pro mist filter.

Diffusion to reduce sharpness is used sparingly because it will also lower contrast. It is not recommended to use filters that reduce contrast with video (video has little contrast)

Nets can be used as well to take the edge off the picture. However, nets can’t be used behind the lens, because sometimes they are visible. Softer lighting is more commonly used to soften the image. Hard lighting is not necessary with tape.

Q: What methods are employed to reduce depth of field in video shooting? Are camera positioning and focusing techniques used?

To bring the aesthetic look of film to Digital Betacam or hdtv use longer lens with wide aperture settings. To increase depth of field, open up the lens and keep it wide. Note that a wide aperture can be a problem with video as the lens is not as sharp as film: f 1.4 is not the same in film and video.

Avoid adjusting the gain on the camera for exposure. However gain is sometimes adjusted down.

Use nd filters to lower the f stop value.

Move the camera back from the subject.

Q: What technical considerations are there in shooting in 4:3 and 16:9 aspect ratios?

For shoots where material is to be released in 4:3, use the tv safe marks, the same as Super 16mm.

For 16:9 shoots, lights and mics have to be moved out wider from the subject.

There are primarily composition issues in shooting 16:9. One problem, from a composition standpoint, can be filling the frame.

There can be depth of field problems when using wider angle lens.

Q: What other dtv and hdtv technical considerations are there? Are there any future scenarios you can foresee?

Up converting from sdtv to hdtv is not recommended as ntsc artifacts are carried over. It is better to shoot hdtv and down convert to sdtv.

Pan and scan for hdtv video is a simple process. There are hdvt vtr’s (Sony HDW500, for example) equipped to do this. It is a similar process as pan and scan in film transfer, scene by scene.

hdtv is more sensitive to light. In some circumstances this can reduce time needed to light. It is not necessary to use as much fill light.

Q: sdtv cameras (digital 525 lines), such as the Sony DVW 700, are switchable between 4:3 and 16:9 recording. Have you worked on a video project shot 16:9 that was to be released 4:3? If so, were there any special considerations made for shooting the project?

The main difficulty shooting 16:9 for 4:3 release is having to compromise on the composition.

16:9 is a better format for composition. It is possible to create more interesting scenes but keeping things out of the shot is more difficult.

There is a compromise shooting 16:9 for 4:3 release: headroom of subject is a key issue.

Q: What kind of testing is necessary when comparing the viability of shooting tape over shooting film?

It is important to test the performance characteristics of the medium. High-speed photography (video has a limit in high-speed photography of 90 fps (frames per second). Film is capable of higher shutter speeds. Clarity of a video image drops in the high fps range. You see a trailing of the image.

High-speed video shoots have given excellent results in beer pours for commercials (50 frames per second).

The mixing of formats, common in compilation projects, can prohibit the use of high-quality video capture on original material because it is difficult to blend in with archival scenes. It is instead better to use one of the new 6mm dv formats for these projects.

The limited availability of lens can restrict shooting in video. Extreme close-up shots, for products and food for example, are difficult in video because of the limits of available lens (there are no prime lens, for example).

Q: How is field audio recording handled?

In field audio recording there is flexibility in the methods. Normally a duel system used (i.e. a separate audio recording system). Usually audio is recorded on timecoded dat two track or DA88 eight track. The system can be hard wired to the camera or wireless.

In the case of wireless audio recording, a ‘Clock-It’ box (a sync generator and timecode generator) is attached to both the camera and the audio recorder to synchronize timecode information

The following is a brief technical comparison between film and video.

Picture resolution

Picture resolution is determined by shooting a resolution test chart. The chart has samples of varying line resolutions on it, beginning at 200 lines ranging up to 1000 lines. No matter what camera is used, the number of these vertical lines visible determines the resolution of the camera.

Measured in TV Lines per

Picture Height (tvl/ph)

HDTV: 1000 tvl/ph

NTSC Video: 750 tvl/ph

Super 16mm: 500 tvl/ph

Signal-to-noise ratio

Signal-to-noise ratio is the measurement of background noise or grain in a picture. It is expressed in decibels or db. A high number is better. Every 10 db increase in signal to noise ratio is the equivalent of a 10 times decrease in noise.

HDTV: 54 db

Super 35mm: 50 db

Super 16mm: 42 db

Dynamic range

Dynamic range is the range of brightness from the darkest to the lightest object in a scene without overexposure. The range is expressed in f stops or aperture settings of the camera lens.

Video: 11 f stops

Film: 9 f stops

Lighting Techniques

Q: It is said that to achieve a ‘film look’ on tape, you light the same way you would a film shoot. Is this true? If it is, briefly explain what defines film lighting.

What could be termed ‘film lighting’ is the use of single-camera lighting techniques. To create an image that does not have a classic ‘video lighting’ look, the dop will light to create a high-contrast image.

The difference between lighting for film and lighting for video has diminished with the manufacturing of faster film stocks.

High-speed film has made lighting between video and film similar.

It is common to use the same number of lights and the same type of lights for a video shoot and a film shoot.

It is important to keep in mind that picture quality is dictated by a) the lighting and b) the camera mounting and movement.

For this reason it is common to use a gear head for the camera in both video and film productions.

There are few restrictions in video production, but several worth noting. Cables from the camera to the monitor and the audio recorder (wireless audio recording is possible)

Why make video look like film? The objective should be to make pleasing pictures with the medium you are using. It is impossible to make video look like film. Lighting is the main factor in creating aesthetically pleasing pictures.

Q: How important is the use of color monitors to check framing and image quality? Are there any special guidelines for determining the image look (exposure, color, composition) when shooting hdtv or Digital Betacam?

The use of a good monitor (digital component monitor) is important for checking lighting during production. It is sometimes preferable to use an operator for these shoots in order to stay close to the monitor.

Balancing color temperatures of different light sources is not as critical in video production. You can see on monitor if you have a problem with mixed light sources (in film you have to color balance light sources because you can’t see what your getting).

Q: Are there specific foreground lighting and background lighting considerations for hdtv and Digital Betacam shoots?

The background color temperature is not as critical in video. It is no longer necessary to always use an 85 gel on windows in the background (to balance daylight with tungsten lighting).

Having a little blue light spill from the background is acceptable.

It is important to make the foreground subject stand out. Concentrate on foreground lighting and let the background fall off.

Q: Are there special considerations to take into account for practical lighting sources in hdtv and Digital Betacam shoots?

Practical lights mix better with other light sources in hd shoots. In many cases, color correction in post is not necessary because you can see what you get on set.

Q: How is exposure measured when lighting hdtv and Digital Betacam shoots? What are the considerations for using or not using light meters when lighting tape? Is using a light meter when lighting tape different than that of film?

With video you can light by eye (using the monitor). A meter is used for key lights only. The rest of the scene can be lit by eye (if at all).

A light meter is usually used on location surveys.

In commercial shoots, there is a comfort level knowing clients can see the image on monitor, because they know the look they are getting.

A light meter is used to verify exposure ratios. A spot meter helpful for checking exposure details in the scene.

HDTV review

Because of the high-definition picture it is recommended to light hdtv as film.

Lighting faults are more visible.

Exposure errors are more noticeable: video won’t handle highs and lows like film (use a light meter with a digital component monitor and wave form/vectorscope).

Bad composition is more noticeable.

Errors in make-up are more noticeable: makeup must be retouched more often.

hdtv renders chalky whites (which can be adjusted in post).

Excessive sharpness: background and set details will show; image can be softened using filters on the lens.

Flat image: depth of field is greater than film and must be reduced. The camera can be moved away from the subject (some say by at least 15 feet) to reduce the depth of field.