Friday, April 20, 2007

Choosing the right weapon...

Once you find a camera that meets all of your needs, don’t stop there. Learn everything there is to know about that camera. Some of them are quite daunting and navigating the menus can be a very in-depth venture, but the more you know about your camera, the more comfortable you will be using it. Learning the camera is also important when little things go wrong and requireThe most important and oft-used item in a crime scene investigator’s inventory is the camera. In a market that is saturated with hundreds of choices, how do you find a camera that is best suited to your purpose? The search becomes a lot easier if you know the specifics of what you’re looking for.

Begin with the type of camera. Do you want digital or 35mm? Most agencies have made the switch to digital for several reasons. You don’t have to pay for film and film development which costs more over time than the camera itself. You can see the photographs immediately which is incredibly helpful when using difficult photography techniques like Painting with Light or Alternate Light Sources. You also don’t have to constantly swap out rolls of film on larger scenes. There is only one drawback with digital cameras and that is storage of your photos. They can easily be stored on CD but there is some concern over the archive capability of CDs. The main concern is how long will CDs last and how long until they become obsolete. You may be forced to transfer all of your stored photographs to a different media several years from now as technology advances. In my opinion, it won’t be long until 35mm film is obsolete and, unless you have your own photo lab, you won’t be able to print the pictures. So let’s discuss digital camera options.

Almost everyone is obsessed with mega pixels. It’s not necessary. Once you get to a certain point, there is no need to go any higher. Higher is better, but not necessary. A 6 mega pixel camera is capable of taking high quality photographs that rival 35mm. Let’s move on to more important considerations.

Crime scene investigation requires flexible photography options which means that the lens is as important as the camera. Digital cameras have what it known as a ‘crop factor’ which means that a 28mm lens will act like a 35mm lens when used on a digital camera. The photograph on the right was taken with a 35mm camera using a 50mm lens. The white box represents the photography area of the same lens on a digital camera body. I prefer to carry 3 lenses. The primary lens is an 18mm-120mm zoom lens. By having a lower range of 18mm, my lens is capable of photographing a large portion of a room in one shot. There is a very slight fish-eye effect at 18mm so don’t use that setting for photographing where scale is important. By having an upper range of 120mm, I can stand in one area and take several shots while zooming in to give reference points to important items. It’s a very good overall lens. I also have a macro lens for close up photography which I use for tool marks and latent prints. The third lens is a 70mm-300mm telephoto which I use when doing surveillance or taking aerial photographs. Because of the lens requirements, you should look for a camera body that has a removable lens. If you already have a collection of lenses, make sure the camera body is compatible with those lenses. Just remember the crop factor. You might end up needing a wider angle lens with your new camera.

Another area to consider is the flash. I like having a built-in pop-up flash on my camera just to have as an extra option, but you really need to make sure that the camera also has a hot-shoe for attaching external flashes. There are several conditions that will require you to take the flash off of the camera and hold it off to the side, like when photographing footwear or tire impressions. You can’t do that with a built-in or straight-on flash.

A minor point to consider is what kind of storage media does the camera use. There are several types out there which can make it difficult to decide. Look at the different types of media like Compact Flash, Smart Media, Secure Digital, Micro-drive, XD, Memory Stick, etc. and compare the cost of each and the available capacities. I prefer to use 512MB cards over larger ones. Because of the lower cost, I can buy more for the same money but I can use a different card for each scene if I don’t have a chance to download the pictures between scenes. Plus, 512 is usually more than enough to capture an entire scene. Compact Flash is small enough in size to store yet big enough to handle with ease, unlike XD cards which are so small that they are very difficult to manipulate. They are also very sturdy and can take a lot of abuse unlike Micro-drives which having moving interior parts and are not very shock resistant. Many professional cameras have the ability of using more than one type of storage media which adds flexibility.

Finally, look at the camera’s available settings. Try to find one that has the option to switch between Automatic/Program (P), Shutter-speed Priority (S), Aperture Priority (A), and Manual (M). Most of the time, you can use the Program setting to have the camera adjust each shot automatically for the lighting conditions. You will also need to have the Manual option for advanced techniques, primarily, Painting with Light. Another important consideration is the availability of a Bulb setting which means that the shutter will stay open as long as the button is pressed. You’d be surprised how many professional cameras have a maximum exposure of 30 seconds with no Bulb setting. Also, look for a camera that is capable of using a mechanical remote shutter release cable rather than electronic. Mechanical remotes are usually less than $10 but electronic remotes can top $80 easily.

 a little attention. For instance, getting the F-ee error can be caused by something as simple as the F-stop being improperly set on the lens and can be corrected by rotating the F-stop ring to the proper setting. There are also a lot of little things built in to the cameras, like white balance, that can help you if you know about them and hurt you if you don’t.