Affordability
Affordability is of course important to any videographer. For nature videographers working in sometimes difficult circumstances in the field this may matter more than usually. For one thing, the unit may be at risk from a dunking in the sea, from being squashed by an angry elephant, or from falling off a cliff. One hesitates in putting a $50,000 unit at risk! Worrying about the fate of a unit may reduce one's willingness to experiment or take risks. For another thing, if you are going on a field trip far from home, perhaps an expensive once in a lifetime trip, you would ideally like to have a backup unit. If finances mean that you have only one unit, it doesn't take much to see that the trip could be a total shooting waste if anything at all happens to your one unit. All still photographers going out on a major trip take two or more spare cameras. Videographers should do the same if they can.
Low Weight
Low weight is also a very desirable characteristic. If you have been involved in still photography and have been bemoaning the weight of your 35 mm camera equipment, get ready for much more moaning and groaning. A full Betacam SP outfit (with only one unit) may weigh 50 lbs or more. Camcorders may weigh 20 lbs or more, then add spare batteries, tapes, tripods, lenses, microphones, etc. There is no doubt that our basic MII field outfit weighs much more than our 8x10 inch still photography outfit. The weight becomes a real issue if you have to hike in any distance. The weight also becomes a real issue while travelling. Many airlines now have strict restrictions on weight for cabin luggage.
Small Size
Size is somewhat related to weight. The issue of size becomes critical when considering airline travel. Some units are so large that they cannot be made to fit in cabin luggage. How do you feel about putting your valuable unit in the luggage hold? Some pieces of equipment can be so large (tripods, parabolic microphones) that they are a nuisance in the field or in a vehicle. Finally, the larger the equipment is, the more likely you are to attract the attention of other people. Some people seem to like having equipment that draws the attention of other people, however let's assume for the moment that you are really more interested in shooting nature then having the biggest phallic symbol around! The attraction of other people can be a real problem when shooting. It's hard to keep shooting while people ask you about your equipment and how much it costs! The attraction of local officials (do you have a permit to shoot here?) is also a potential negative aspect. Finally, large equipment may attract the attention of those people who would be only too happy to help relieve you of some of that heavy equipment!
Robustness
Video equipment is complex and sensitive to temperature, humidity, and shocks. You should handle your equipment carefully, but that isn't always possible. Better quality units are made to withstand some rough use, but video equipment is more sensitive than movie equipment or still photography equipment. There are going to be times in the field when equipment falls, gets wet, is covered by sand, and is generally abused. The ability of your equipment to keep going will prove vital.
Video Quality
If you are going to be spending a lot of time and effort to get few seconds of footage of the elusive Jerdon's Courser in India, you want to make sure that your video will be of top quality. There is nothing so frustrating as to spend weeks getting footage and then deciding that the basic quality is just not up to par because of inherent limitations in the videotape format or your equipment.
Interchangeable Lenses
Nature videographers need interchangeable lenses. The built-in lenses of lower cost camcorders are fairly good but they are not up to the quality of the very best video or still lenses. The lack of quality is often evident. Also the zoom range, although extensive by 35 mm still photography standards, is never really totally satisfactory for nature work. The use of wide angle and telephoto adaptors that can be screwed on to the outside of the built-in lens can help a bit. However very good quality adaptors are reasonably expensive ($500 to $1,500) and are limited in range. Cheaper adaptors or adaptors of greater power are generally not optically acceptable. Built-in macro functions don't give you flexibility that you may be used to from using bellows or specialised macro lenses in 35 mm still photography.
A Good Viewfinder
Once you use interchangeable lenses, you will have to rely a great deal on your viewfinder both for focusing and for exposure determination. Built-in lenses typically have fully automatic functions and people often use the viewfinder strictly for aiming and framing. Most interchangeable camcorders have some limited automatic functions on the zoom lens that comes with the camcorder, typically exposure control and zooming. However, the more specialised lenses that you may use, such as 35 mm still photography macro lenses or long telephotos, will not have any automatic control. (Note: the exception is the use of Canon 35 mm EOS lenses on Canon L1, L2, and XL1 camcorders.) Proper focusing on a small low resolution screen can be very difficult. The colour viewfinders on many recent camcorders can be a real problem for careful focusing. Even when you have automatic focusing capabilities you may choose to override them and use manual focusing. It can be hard for the camcorder computer to realise what element in the picture is most important to you. Also nothing is quite as disturbing as the constant in-out focusing displayed by some camcorders. Make sure that you check the quality of the viewfinder very carefully before buying any camera!
A great help in manually adjusting exposure with interchangeable lenses is the use of zebra patterns in the viewfinder. When the zebra pattern option is enabled, a distinctive white pattern is visible in areas of the picture on the viewfinder which are "over-exposed", to use a film analogy. This can be essential in helping you adjust the exposure levels accurately.
Audio Capabilites
The importance of good audio tends to be ignored to some extent, both by manufacturers and by inexperienced buyers. After all the medium is video isn't it? But audio is critical to good video. At times one can put up with poor video (look at the quality of much television reception!), but usually one can't put up with poor audio. Manual controls for audio and other functions are obviously important. Audio level meters are essential for proper manual adjustment of audio levels. Other needed audio features include the provision of professional balanced (XLR) microphone contacts for external microphones (there are some external XLR adaptors that can be added to some camcorders that don't have them). Good nature video will often require specialised microphones (shotgun microphones, parabolic microphones, wireless microphones) to pick up subtle sounds at some distance or insect sounds close up.
Low Light Capabilities
Often you will have no control of the light conditions, either because you will not wish to affect the scene or the organisms or because the subject is too far away. Often also you will be working in comparatively low light conditions such as in deep woods, in dens, or near nightfall. Thus a camera capable of working under low light conditions can be important.