58 UNDERWATER GUIDE TO MARINE LIFE 



waters like the Bahamas the authors prefer CCM :^20 or #30. These filters 

 will give an overall balance of color with a slight blue-green effect without 

 introducing a large filter factor. Be sure to include the filter factor along with 

 the exposure meter reading to get your camera exposure setting. For instance, the 

 filter factor for a CCR #30 filter is 1.8. 



Black and white pictures show increased contrast if a filter of the series 

 CCY (color-correcting yellow) is used. A CCY #10 or #20 is adequate for 

 most waters. All these filters are available in gelatin sheets at low cost, and they 

 may be cut and mounted on the back or front of still or movie lenses, or pasted 

 on the inside of the camera case in front of the lens. When using filters and a 

 meter it is possible to put the same filter over the meter to eliminate exposure 

 computation involving filter factors. 



Film 



Films for underwater photography are the same as used above water. Consider- 

 ing that most underwater lighting conditions are of a low light level, the best 

 color films are the faster speed Anscochrome and Ektachrome. Ektachrome gives 

 good results, but Anscochrome gives better color rendition under water. The 

 exposure latitude is one stop under and over ideal exposure for good color 

 rendition. 



Black and white films have a wide exposure latitude with three stops above 

 and below ideal exposure giving a workable negative. The best films are 

 Panchromatics with an ASA 50 emulsion speed or better. For caves and poor 

 lighting conditions found near reefs, take advantage of the faster speed films. 

 However, increased speed of film usually results in increased graininess which 

 cuts usability when enlarging. 



Any color film like Anscochrome 16mm. reversal movie film that has an 

 ASA 32 rating and gives excellent color rendition at low light levels is well 

 adapted for underwater use. This film allows the underwater photographer to 

 use smaller lens openings and to shoot under conditions which formerly did 

 not allow color. Anscochrome reversal film allows a latitude of one stop over 

 and one stop under ideal exposures. 



Thin emulsion black and white films have extremely high resolving power, 

 very fine grain, and fair contrast which make them good for underwater work. 

 The exposure latitude of thin emulsion films is about the same as ASA 32 

 color films. 



Film manufacturing is undergoing great changes to which the underwater 

 photographer should be alert. 



Artificial Lighting 



There are tremendous photographic opportunities in waters shallower than 

 about 60 feet for the amateur and the professional. Below 60 feet, in caves, and 

 where poor lighting is found, artificial lighting units such as flash attachment 

 and strobe light units that can be converted to underwater should be used. 

 These units can bring light and color to the blue-green depths. It would 



