Film

Light is what makes it possible for us to see the world around us as an image on film. In case you’re interested, we only see a very small part of the Electromagnetic spectrum that’s out there which include energies like X-rays, Heat, Radar and television and even radio waves. All we have of the spectrum is about 400 – 700 Nanometers of the electromagnetic spectrum, that’s it, that all we can see on are own without the help of some device.

Except for a few special films like Infrared Film, there are three choices for conventional cameras and Ill talk about digital cameras later in this section.

Color Negative Film is the most popular choice used today. Second is Color Transparencies or slides. The third is Black and White film and it is used by some of the finest photographers of all time. Lets take them one at a time.

Color Negative is usually processed in a lab using a process called C-41 Process and you have very close tolerances with temperature as you develop the images and then you have to print it on special color printing paper. You need expensive equipment and chemicals and the knowledge to know how to print color prints. Most people just go to a lab and drop them off and pick up the negatives and the 5x7 prints in an envelope for a small cost.

Color transparencies or slides are more difficult even though you don’t need to do any printing. The process is called E-6 Process and is very expensive to use. The temperature of the chemicals is even more critical to maintain and you have to cut all the slides into pieces and put them into slide holders.

Black and White film is the easiest to develop and print but the most difficult to do correctly. For a few hundred dollars you can buy the processing equipment and an inexpensive but useable enlarger. You can really have fun too, developing your own film your way. The magic of watching your first print come up in a tray of developer is something you’ll never forget.

But to really get all you can out of B&W film you first start out with your camera and alter your exposure. If you know how to use a spot meter and an exposure system like the Zone System you can achieve a lot more tonal range. I’m not going to go into the Zone System here, but you can click on the link and see what its all about and then get a good book on the subject.

In a Digital Camera you meter light and set film speed and anything else needed for a correctly exposed image. The only difference is you’re using a digital camera to capture the image. Here’s how it works.

Light passes though the lens and onto a single CCD Image Sensor in a single array system and is interpolated into the Blue, Green, and Red colors. In the case of a multiple array system the light hits a series of Prisms that splits the light onto the three individual CCDs, one for each color.

Now the digital image data is in full color and it passes to the camera’s computer processor that will make any adjustment it needs to, such as exposure compensation, white balance, contrast or brightness and any noise reduction necessary to create a sharp image. The cameras’ processor does all this and maybe more before it can store the image on a Memory Card, which is why it takes a few seconds for a camera to store an image.

All cameras have a Film Speed setting, or a way to express sensitivity to light. But there is a price to pay for fast film! If you don’t mind large Grain in the image and you’re not going to print enlargements, or if you’re using a grainy look as a mood within the composition, then OK--go for it. But if you’re looking for clear sharp, clean prints that can be enlarged use a slower speed film and a tripod.

Color Balance or the Color Temperature tells photographers what light the film is balanced for. The colors that make up light are measured as color temperature on the Kelvin Scale. Here are some numbers from the scale: 5,500K is daylight; 6,000K is a studio strobe light; 4,000K is about normal for most flash bulbs; 3,200K is a flood lamp; and 2,800K is an average household light.

You can use Lens Filters to correct this if you don’t have the right speed of film to shoot the image.

DX Coding is that crazy patter on the sides of the cassettes and it is there to tell automatic cameras the type and speed of film that you’re putting in the camera.

The speed rating is listed on the side of the box, just look for the ISO/ASA rating, Films that are slow are rated 50-100 and very fast is 400-1000, allowing you to make an image in very low light without a flash.

Exposure is nothing more then the correct amount of light passing though the lens onto the film to achieve the right exposure at a specific speed.

We do this by means of a light meter, within the camera or a hand-held device. There are two ways of metering light, the Reflected Light Meter that measures Luminance, and the light that’s reflected from the subject your filming. This is used in most hand-held meters and all meters built into cameras.

The Incidence Light Meterr is a hand-held meter that measures Illuminance Light falling on your subject. These meters have a much wider angle of view because it has a Translucent Dome of white glass or plastic over the Light measuring cellto diffuse the light. Some meters can do both by sliding the dome on or off the light measuring cell and can be used for most metering jobs.

The Flash Meter measurers the brief burst of light put out from an electronic flash and not the light that is continuously on that the other meters meter.

The Color Temperature Meter is a meter that measures Color Temperature rather then its intensity and is used to determine the color correcting filtration needed when a specific color balance is needed for an image. Cameras use reflected light meters and you first tell the camera the speed you are using and then you have to choose an exposure mode.

Most cameras give you a Fully Automatic Mode where the camera adjusts both shutter speed and aperture based on built-in programming. There is a Manual Mode where you need to set Shutter Speed and Aperture. The cameras built-in meter can be used or you can use a hand-held meter.

Aperture priority lets you set the aperture you need and the camera sets the shutter speed for you. Shutter Priority lets you set the shutter speed and the camera will set the aperture for you. This gives you many options in operating your camera and what your images will look like.

I suggest you visualize your image in your head before you take an image so you wouldn’t be disappointed with the final print or slide. Remember there are many ways to get a correct exposure and still get the affect your looking for in the image.

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Want to know more? Continue the Photo Technique Mini course and learn about Lighting or return to Cameras or Lenses.

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