Traditionally a lot of professional nature filming has been done using film cameras, typically 16 mm and occasionally 35 mm. Film cameras have a lot of advantages over camcorders and VTRs. Film cameras are comparatively inexpensive (that is compared to the best professional video equipment), comparatively simple and robust, remain useful over a very long period, can use the latest improved film stock, and easily accommodate a wide range of lenses. Film has some important inherent advantages over tape, in particular in its ability to capture a much wider range of brightness levels.
However, for many people the advantages of using tape far outweigh the disadvantages. For many people (including ourselves!) the cost advantage of using tape is paramount. Some years back we had calculated that the cost of one hour of processed 16 mm film would be approximately $1,000. In comparison the cost of one hour of Betacam SP or MII tape would be less than $100. In nature filming it is inevitable that you will get a very low ratio of good shots to bad shots. In practice you will find that less than 10% of your footage, sometimes less than 1%, is usable. That means that if you are planning a one hour program you should allow for at least 10 hours of footage and more likely 30 to 50. In other words, in terms of 16 mm film, that might mean $10,000 to $50,000 in film stock alone. For professional tape the amount would range from $1,000 to $5,000.
Another great advantage of tape is that you can check your shots immediately. In the field we typically view all of the shots taken during the day that evening. That way we can determine if we need to re-shoot something, whether we were misjudging exposure or colour balance, or if something is wrong with the equipment. With film you are going to be "in the dark" usually until the end of your field work.
Finally with the increasing sophistication of non-linear editing equipment, we can edit much more efficiently directly from tape.
As time goes on tape systems are getting better and better and are getting closer to the technical abilities of film. For those of you that really like the grainy look of film stock, there are computer special effects that you can apply to your tape footage to make it look more like film. For nature documentaries to be shown on television or on VHS tapes for home distribution we frankly prefer the look of good quality tape footage.