Either you opt for a traditional SLR camera or the easier and cheaper digital models, you need to be able to control every aspect of your exposure, mainly for two reasons. First, if you were to use your camera on an automatic setting, you would likely have under-exposed film because a.) meters don't account for the reciprocity failure of film during long exposures, and b.) most meters are not sensitive enough to take an accurate reading at night.Most in camera meters are sensitive to about 1 EV, where as the light of the full moon is about -7 EV. The other reason for using a camera with manual settings is so that you will learn how to accurately estimate night-time exposures in different lighting situations.
Video or camcorders are also very good and should be used. Use brand new tapes. Don't use an old tape and tape over something.
35mm Kodak HIE-135/36 film : R light requires a focus adjustment from visible light. Some manual-focus cameras will have an infrared focus mark to indicate the offset. If not, experiment. The difference is small, but it could be significant.
HIE has a "salt and pepper" grain. It is a nice artistic effect, but the resolution is not the same as conventional and the film is light green! There is no recommended film speed for HIE. A good starting point is 50 or 100 ASA for D-76 processing. A test roll, with exposures logged, is recommended.
An 87 filter The reason for the 87 filter is to eliminate all existing light during photography and only to have the IR on the film. The #87 filter will completely block visual light. A #25 (red) filter can also be used with HIE to block everything except the red visual and infrared spectrum. (Makes focusing a bit easier if you have the light to work with.) HIE is also sensitive to UV light and can get the same type of haze from ultraviolet as daylight film does. HIE with the #87 filter can be used to photograph through fog (or darkness, of course.) It is possible that anything similar to fog could transmit the IR light instead of reflecting it and would not show up on the film.
A good tape recorder and an external static free microphone should be in use at all times in the ghost hunt. Even if you don't hear anything during the hunt rewind the tape and play it back. Spirit voices have been known to be heard on tape later after review. This is referred to as, EVP, Electronic Voice Phenomena. Again, use brand new tapes when recording.
The idea behind this phenomena is to go into an area that you feel could contain spiritual entities and talk with them. Ask questions wait a few seconds then ask some more. It's not important to hear a response (although if you do hear a response you've struck gold). When you're finished go home, rewind the tape and carefully listen to it from beginning to end. You may discover that there are other voices on the tape. They may have even answered some of your questions. You have to listen to the tape very carefully and weed out all the background noises, (cars, dogs barking, the wind!). Many people that have had success with this method tell that the voices are sometimes as quiet as a whisper and can also be speaking in different languages. Details to remember: Use a good tape recorder with a static free microphone. Use a brand-new tape. Don't tape over stuff on an old tape. Try to use the 60 minute high quality tapes. If you are walking with the tape recorder don't bump the microphone. Record in 30 to 45 minutes non stopped sessions. Ask clear questions then wait about 5 to 10 seconds before going on. It won't do much good if you never let the ghosts get a word in edgewise.
Always have bright flash lights (usually 3 or 4) and extra batteries. Sometimes candles may be used but don't count on them staying lit.
A Notebook and pens/pencils:
Notebook is a good way to keep notes, records of time or a journal of events.
These are great! EMF Detectors can pick up electronic fields over different frequencies. Where there are ghosts there are usually disruptions in the electronic field. They are relatively cheap ranging from $24 to $130.
A good thermometer can detect changes in room temperature quickly. It's best to use the old fashion mercury filled, red line, thermometers. They have electronic thermometers but in ghost cases where electromagnetic forces have been reported they might fail right when you need them.
Great for navigation if you know how to use one and also great for picking up those electromagnetic forces. A compass will react to any magnetic or electrical stimulus that is out of the ordinary. Same rules apply here, try not to use the electronic compass's. Stick to the simple boy scout, needle points North version.
(also called, a Spirit Wind Chime)
The idea here is that the spirit will pass by and cause the ghost catcher to chime much like a wind chime does in the wind. You can use the wind chime that you get in the stores, however, try to get the ones made of the lightest material. You don't want the arms to be too heavy. For obvious reasons these will not be affective outside or in any area where a breeze or wind is blowing.
You can make Ghost Catchers yourself. Take about 8 to 10 very thin strips of metal (about one inch wide and about 6 to 8 inches long). Put a hole in one end of each strip. Tie seperate strings to each strip. Leave about 6 inches of slack in the string and tie the other end of the strings to a pole or something that keeps the strips hanging down. Tie them about one half inch apart on the pole. The strips shouldn't touch each other but shouldn't be very far apart either. Hang the pole from the ceiling or in a doorway. I know that some people paint the strips with glowing paint to make them easier to see at night or in the dark. Any variation on a wind chime will work. For the best results make several ghost catchers and put them at different spots throughout a house.
Infrared Thermal Scanner
These saves on infrared film and time by accurately pin pointing the cold spots. These scanners are excellent to use in outside investigations. Price range is around $300 to $500.
Air Ion Counter
Measures positive and negative Ions in the air. This little add-on is a great instrument to have for use in the field. The price is high, around $400 - $600.
When you have a team of three or more people headset commincators are a great idea for staying in contact when spread out. You can use the hand held walkie talkies but the headset frees up your hands for holding cameras etc. They will run in the price range of $30 to $80 a piece. I've seen good sets that work up to a distance of 100 yards for 40 bucks.
Small battery powered spot lights really help at night when it comes to setting up and taking down cameras and other equipment. They can also be used for safety and to get a better view of the surrounding terrain at night. Get the lights that sit on the ground but have swivels on the lights to set them to different angles. Plan on getting between 2 and 6 spot lights depending on your needs.