CS Photography Rules of Thumb

RULE OF THUMB 4.3

All other times—early in the morning, late in the afternoon, at night, or when photographing indoors—lean toward the initial use ofan ISO of 400.

RULE OF THUMB 4.9

Always screw filters onto the lens when the lens is aimed at the ceiling or straight up. This reduces the chances of dropping the filter.

RULE OF THUMB 4.8

Before using an f/5.6, or wider aperture, for a crime scene photograph, consider these options: 1. Use electronic flash. The additional light from the flash will certainly allow the use of smaller apertures, which in turn will provide a better depth of field. 2. Use a tripod. Putting the camera on a tripod will allow the use of longer shutter speeds without the risk of blur, and the use of longer shutter speeds will also allow smaller apertures to be used, which will provide a better depth of field. 3. With a digital camera, reset the ISO to the next faster ISO setting. That will enable the use of both a 1/60 and an f/8, with the ISO setting used to create the +1 exposure.

RULE OF THUMB 4.4

For accurate color capture, only use either midday sunlight, which is approximately the bright yellow sunlight from 10 am to about 3 pm, use an electronic flash, or ensure the digital white balance setting is set for your current lighting.

RULE OF THUMB 4.5

If an exposure error is unavoidable, it is better to underexpose digital images a bit. More detail can be obtained from a digital underexposure than a digital overexposure.

RULE OF THUMB 6.4

If the flash recycle time exceeds 30 s, it is time to replace the flash batteries. Major crime scenes are not the place for you to be waiting long periods of time for the flash to recycle.

RULE OF THUMB 5.2

If you are composing on an area in your image, the entire area, from front to back, should be in focus.

RULE OF THUMB 5.7

In surveillance situations, to be confident there will be adequate magnification to recognize either a subject's face or to read a license plate, you should use a lens that has a focal length of 2mm of lens per foot of distance between the camera and the subject.

RULE OF THUMB 6.2

Manual flash used outside is at least one stop less bright than what is suggested by the flash LED screen.

RULE OF THUMB 6.1

Most flash units are not designed to be used at distances closer than 2′. When doing close-up photography, resist the urge to bend the elbow of the arm holding the flash unit. Try to keep this elbow straight so the flash does not get too close and overexpose the image.

RULE OF THUMB 5.8

Never use the two smallest or the two largest apertures of the lens' f/stop continuum when critical comparison (examination quality) photographs are taken.

RULE OF THUMB 5.5

On bright sunny days, ISO 100 film will allow photography with the small F-Stops. Otherwise, on cloudy or dark days, at night time, or indoors when using electronic flash, use a faster ISO film like ISO 400.

RULE OF THUMB 4.1

Outside, during the middle of a sunny day (loosely equivalent to 10 am to 3 pm), select an ISO of 100.

RULE OF THUMB 5.3

The DOF extends 1/3 in front of the point of exact focus, and 2/3 behind the point of exact focus.

RULE OF THUMB 5.1

The entire scene, and all the evidence within the crime scene, should be in focus. If you know a part of the scene will be out-of-focus, you should attempt to recompose the scene so the out-of-focus area is no longer in the field of view.

RULE OF THUMB 5.6

The use of a different focal length lens may introduce lens distortion into a photograph. Wide-angle lenses will elongate the distance between the foreground and background. Telephoto lenses will compress the distance between the foreground and background. Only the 50-mm lens will capture the image without this distance distortion.

RULE OF THUMB 4.6

To eliminate possible blur from hand-holding the camera, use the shutter speed that is the closest to the focal length of the lens on the camera, inverted into a fraction.

RULE OF THUMB 4.7

To the extent possible, most crime scene images should be captured with a shutter speed of 1/60th of a second in combination with one of these four f/stops: f/22, f/16, f/11, and f/8.

RULE OF THUMB 5.4

When attempting to maximize the DOF with crime scenes ranging from 5'-30', the most effective way to do this is to focus at a distance which appears to be midway between the top and the bottom of the composed image in the viewfinder.

RULE OF THUMB 6.3

When you are 5′ or closer to your intended subject matter, remove the flash from the camera's hot-shoe, so it can more accurately be aimed at your intended target.

RULE OF THUMB 6.6

When you are using bounce flash, if the subject of the photograph is 9′ or farther from you, you many need to use an f/5.6 or a wider aperture, which will diminish the depth of field. Consider ways to get closer to the subject to avoid having to use wide apertures. Or, consider bumping up the ISO from 400 to 800.

RULE OF THUMB 6.5

When you are using flash, pretend the world beyond about 42' to 46' does not exist, because beyond that, the scene will either be underexposed or a wider aperture will have to be used, which results in a smaller depth of field range.

RULE OF THUMB 4.2

Whenever capturing examination quality/Critical Comparison Photographs, use an ISO of 100.