Intensity and Positioning of photographic lighting equipment
Brightness (Quantity): How many times have you heard the phrase "we need more light"? If you're shooing with a tripod and you're shooting something that doesn't move, you really don't need more light. You may prefer that the light be coming from a different direction, but chances are if you can see it, you can shoot it. If the shutter speed is so slow that either you or the subject will move, you will need a tripod to create a "sharp" image on film. As for a properly exposed piece of film, the amount of light needed isn't a big deal, that's what aperture and shutter speeds are for. Weather you stick the light right next to the subject or move it 100 feet away, you can produce a properly exposed image on film by compensating with those buttons on your camera. If you want to become a good photographer, you must understand this concept. It's not the amount of light, it's how you use it. (concept sound familiar?)
Main Light: What is the Main light? The main light is the light that creates form (highlight and shadow. The sun is a great example of a main light. The main light in a picture can also be an umbrella or an Vivitar 283. Probably the most important decision you will make when creating a photograph is, where will the main light be? Should the sun be over my shoulder, or the subject's shoulder. Should I put the subject beside the window, or in front of the window. Should I keep the flash "on camera" or should I get an extension and place the flash off to the side? Where is the best place to put the main light? The answer is
It depends. Every case if different, there is no right or wrong. If you like the final result, then you've made the right decision, if not, call it art. The real key is to SEE the light. See what's being lit and not being lit. If you don't like the results, move the light! (or the subject in reference to the light) Do you want the sid of the face black? Do you want Rembrant (sp?) lighting (one side of face lit and a triangle of light on the other cheek)? Do you want those eyes in shadow? If not, move the light! See what the light is doing and then adjust. Forget about all those buttons on the camera for a minute. See what the light is lighting and what it's not lighting. It's very important. Where you put the main light will create smoothness (light near camera) or texture (light skimming across the subject). Light is the main tool of the photographic artist. Paint texture and darkness where you want it.
Number of Photographic lights: Here's a quiz for you. How many light sources did God Create? One, the sun, right? Well, not really. He also created the sky and the ground to "bounce" the sun's light back into the shadows. We call that "bounced back" light "Fill" light. If there was no bounced back fill light, anything not being lit directly by the sun, for example the shadow side of a face, would be completely jet black! .
Fill Light: The light that makes the "shadow side" of things visible, we call FILL light. In photography we define the fill light as one not creating any (as few as possible) visible shadows. The best way to achieve this effect in photography is to place the fill light as close as possible to the camera's axis. All lights, no matter where thy are or how big they are, create shadows. But
by placing the fill light as near the camera as possible (and above), all the shadows that are created by that light are cast behind the subject and are therefore less visible to the camera. Another way to create fill light is to us a "fill card". Some photographers use large white cards, foam core, or flexfills. The idea is to place the fill device on the opposite side of the subject as the "main" light, so light is back into the subject to lighten the shadows. How much light do you want to bounce back or add as fill? How close to the subject do we put the fill card? Depends
Light Ratio: How much fill light should I use? In other words, what should the exposure ratio of the main light to the fill light be? Should the fill be the same brightness as the main light (1:1) or should the main light be twice as bright as the fill (2:1) Again, it's very subjective, with no right or wrong answer. Some people refer to low light ratios as "soft" light because the shadows are light and refer to high light ratios as harsh light. The basic rule of thumb is
The higher the ratio (the less fill), the more "dramatic" the shot. If you want to create drama, use less fill light. I've seen some really nice pictures with very low main to fill ratios (fashion magazine covers come to mind), and I've seen some super shots where the sides of faces have gone completely black. Let me make a suggestion. If you can't decide what ratio you want to use on your next portrait, try looking through magazines for pictures you really like, Are the light ratios high or low? Was the camera near the camera are far to one side? Are the eye sockets lit? Are both side of the face lit, or just one? See what it is about other people's photos that you like. Use that information next time you shoot. Experiment and keep notes. See what the light is doing, and adjust!
Other lights: Yes there are other lights. There are hair lights, background lights, rim lights, and god knows what other kind of lights. Don't worry about those, that’s more advanced stuff. You can take great people pictures if you just worry about the two lights mentioned above.
Photographic Light Equipment Source Quality
Source size: Another quiz
Which is the better to light to use on people, umbrella light or a small electronic flash? Wrong! Again, it all depends what you're trying to say with your picture. It's like asking a painter which is the best size brush is best to paint with. It depends on what the heck he's painting. The difference between an umbrella and an on camera type electronic flash, is it's relative size. The bigger the source, the "softer" the shadow. If you want texture, use a small light source, if you want smoothness or softness, use a large light source. Try this. Take the shade off of a lamp in your living room (bare bulb - small light source). Get somewhere in between the lamp and the wall. See if you can make ducks (shadows) fly across the wall. Now, put the shade back on (larger light source), and try it again. You end up with "softer" ducks (shadows). It's the same with the shadow of the nose on someone's face. In most situations, people don't like to see the exact shadow of their nose on their face, That's why most portrait photographers us umbrellas, they are large light sources, which translates to softer shadows. Please don't get confused between the softer shadows (large light source) and what some people call soft light (low light ratios). Here are some example of large light sources: bounce light into the wall (the size of the wall becomes the size of the light source) and the sky on an over cast day(very big source).
Color: Another quality of light that makes more of a difference is the color of the light. If you shoot negative film, this isn't really an issue because the lab will adjust the color to whatever color they feel like when the print it. If you shoot chrome, though, then it's kind of fun to play with color. A warm filter on the light can really change the mood or a photo, but this topic is a little more advanced than I had intended to cover here. Maybe later.