The following photometric quality criteria are significant for television and film recordings:
vertical illuminance and corresponding uniformity
ratio of horizontal and vertical illuminance
uniformity of horizontal illuminance
colour temperature of the lamps
colour rendering of the lamps
lighting levels of spectator areas
For television and film recordings, lighting of vertical surfaces is particularly important. Values for vertical illuminance Ēv;m (maintained local average of Ev) apply to a horizontal assessment plane at 1,0 m above the floor and the grid points assigned to each sport in EN 12193.
If the main camera is situated at an unspecified position at the long side of the sports area, e.g. a handball field, the lighting must fulfil requirements regarding lighting level and uniformity directed onto this long side.
In rarer cases where only one camera is defined to be the main camera position, it is sufficient to fulfil only the requirements for vertical planes directed onto said main camera.
If the camera position is not subject to any limitation, illuminance levels on the vertical planes towards all four sides of a field must be achieved.
The level of vertical illuminance mainly depends on the speed of the sport, the recording distances and the recording angles. Sports can be subdivided into three categories – A, B and C – with speed of movement during camera recording and dimensions of the objects to be recorded being the main determining criteria. Table to table provide information as to which sport is assigned to which group.
Maximum recording distance and sports group determine maintained vertical illuminance. The values according to figure are not suitable for cases where regular slow-motion recordings are made. For such cases, a higher lighting level is required.
Illuminance in the direction of the TV camera determines the quality of televised images. It is therefore customary to determine illuminance on a (usually tilted) plane which is vertical to the optical axis of the recording camera and thus points directly to the (specified) camera.
(a) Illuminance in the direction of the TV camera determines the quality of televised images. It is therefore customary to determine illuminance on a (usually tilted) plane which is vertical to the optical axis of the recording camera and thus points directly to the (specified) camera.
(b) Maintained vertical illuminance Ēm,v in relation to recording distance d (distance between camera and recording detail)
Figure 3.104: Vertical illuminance for camera recordings
Table 3.75: ORF requirements for vertical illuminance in television recordings
Uniformity of the vertical illuminance in planes parallel to a playing field side where the main camera is located or for a specified camera position shall be
Ev,min/Ev,max ≥ 0,4
with Ev;min being the minimum and Ev;max being the maximum vertical illuminance in lx. Uniformity of vertical illuminance values at a single grid point averaged over four planes parallel to the four sides of the sporting area shall be:
Ev;min/Ev;max ≥ 0,3
Since the illuminated horizontal area also constitutes the main portion of the observance field of the camera, it is important to provide a sufficient horizontal illuminance portion. A sufficient ratio of horizontal and vertical illuminance is achieved if the average horizontal illuminance Ēh in relation to average vertical illuminance Ēv (based on each side with the main camera or in the direction of the main camera position) is within the following interval:
0,5 ≤ Ēh/Ēv ≤ 2
The uniformity of the horizontal illuminance in a sporting area must be:
Ēh,min/Ēh,max ≥ 0,5
It is also important to avoid major changes in horizontal illuminance over a certain distance. For example, the maximum change in horizontal illuminance must not exceed 25% per 5 m on large playing fields such as handball fields.
In indoor facilities with a significant daylight portion, the colour temperature of the artificial lighting must be between 4.000 K and 6.000 K if artificial lighting is switched on in daylight or twilight hours. Where no perceivable daylight influence exists, the range of the light sources’ colour temperature can be increased to anything between 3.000 K and 6.500 K.
The lighting’s colour rendering index Ra must always be above 65, values of at least 80 are preferred. Modern, quality LED luminaires usually feature an Ra ≥ 80 and thus also fulfil the requirements here.
Spectator areas with sports fans’ emotions and moods often provide the backdrop for television and film recordings. It is therefore desirable to also illuminate adjacent spectator areas overlooking the playing field. To that effect, an average vertical illuminance of at least 25% of the average vertical illuminance of the sporting area should be achieved for the spectator area.
The aforementioned specifications on lighting for television and film recordings are based on EN 12193. Beyond that, specifications of national and international sports associations as well as companies responsible for television broadcasts must be considered (see table and table). In particular, the publications of the General Association of International Sport Federations European Broadcasting Union (G.A.I.S.F.) and the European Broadcasting Union (EBU) by the title "Guide to the artificial lighting of indoor and outdoor sports venues" (2006 edition) are helpful. Considering the multitude of provisions which, partially, have to be observed very strictly, lighting design for sophisticated television and film recordings is generally reserved for experts.