To photograph shoe and tire impressions, blood spatter, in low-light conditions, or to paint with light, the photographer needs a shutter-release cable or cord. For older manual 35mm SLR cameras, the shutter-release cable is a mechanical plunger-type cable, with a lock nut on or near the shutter-release plunger button, that screws onto the top of the camera's shutter-release button. Automatic 35mm SLR film and digital SLR cameras use a shutter-release cord that mounts to an electronic connector on the camera body. Both the cable and cord can be had at most local camera shops, online or by special order at electronics stores selling 35mm film SLR and digital SLR cameras.
One of the required little things is a good set of rulers. Not the type teachers once used to rap unruly students across the knuckles, but 3- and 6-inch evidence rulers. These little jewels come in an assortment of colors including white, black, gray, orange and hot pink. Unless I am shooting with an alternate light source, I prefer a gray ruler. Evidence rulers have a standard and metric measure, and when used in close-up photography they provide a perspective of the evidence's size. Photographs containing evidence rulers also permit the photo to be accurately enlarged to a 1:1 ratio, or life size.
Many crime scene evidence supply companies offer pre-printed evidence labels that also incorporate a ruler. These little cards, typically a one-time use item, are neat but not very cost effective. A ½-inch wide roll of smooth, weatherproof first aid tape solves the labeling problem quickly and cost efficiently. Simply tear or cut off a 1- to 2-inch strip of tape, apply it to a 6-inch evidence ruler, below the measurement markings, and label the tape with the item number, case number, date and photographer's initials for evidence identification.
Another handy and useful item to toss in is a couple rolls of two-sided tape. Two-sided tape secures an evidence ruler to vertical or overhead surfaces and can hold the ruler in place during windy conditions. Any crime scene photographer who's had to photograph blood spatter or bullet holes in a wall or ceiling will attest to the usefulness of two-sided tape.
Crime scene photographers using manual 35mm SLR cameras must tuck in an extra camera battery as well. There is nothing worse than having the camera battery die at 2 a.m. half way through a crime scene shoot. On the same note it also would be a good idea to include both an AC and DC charging cord in the kit if the camera uses rechargeable batteries.
Because criminals don't check the weather forecast before committing their crimes, a rain cover and lens hood for the camera and lens is in order to prevent fatal moisture damage. Good quality rain covers and lens hoods are available at camera shops and photographic supply stores. If caught off guard, a 1-gallon freezer bag with a lens hole cut out works in a pinch to protect the camera but provides little or no protection for the lens.
Finally include several Sharpie or similar-type weatherproof markers in both medium and fine tip in the kit. These markers are indispensable when it comes to labeling evidence bags and the tape used on evidence rulers. One evidence tech I know keeps an assortment of Sharpie Mini markers on similar colored lanyards around his neck. He uses a different color marker for each room he photographs and processes.
If budget constraints are not an issue, there are an array of gadgets and gizmos designed to simplify the crime scene or evidence photographer's job. The following items also could be included in the ultimate photographer's toolkit.
A Quantum or similar type rechargeable battery pack will operate a flash unit for days, so to speak. This device could be included in the must have items if the photographer does a lot of flash photography. One caution when using these battery power packs, be sure to allow the flash to adequately cool during multiple flashes. I have found that if not careful these powerhouses will melt a flash unit in a New York minute.
An adjustable output ring flash, which mounts to the front of a lens, is extremely useful when photographing bite marks, dental work or in nearly any other close-up photography. An adjustable output ring flash, while costly, between $450 and $700, is worth its weight in gold.
Two or three extra flash units capable of operating in the master/slave mode are extremely useful for painting with light and other nighttime photography. While actual flash units with master/slave capability run between $300 and $500 each, there are several dedicated slave flash units on the market for around $50 each.