What is light and how do we use it
Light is the electromagnetic radiation visible to the human eye. In classical physics the wave of electromagnetic radiation has amplitude, which is the brightness of the light, wavelength, which is the color of the light, and an angle at which it is vibrating, called polarization (reflecting windows anyone?). In quantum physics electromagnetic radiation consists of particles called photons, which are packets ("quanta") of energy which move at the speed of light. The brightness of the light is the number of photons, the color of the light is the energy contained in each photon, and four numbers (X, Y, Z and T) are the polarization.
And as weird as it may seem experiments show that both interpretations are correct.
Photographs are impressions of the electromagnetic radiation called light on an impressible medium, such as the digital sensor or the photographic emulsion. Light reflects from the surfaces that we photograph (people, objects, nature) thus giving us the colors and forms.
If we calculate the exposure of this medium as too high or too low we will have a blown out, overexposed image or a too dark image (anyone familiar with that refusal?). If the intensity of the light is too low in one part of the image and too high in another part we will also have an unusable image.
Before digital and fancy film cameras there were manual cameras were the film was drawn by hand and the exposure was at the mercy of the photographer's eye. It depended on your ability to measure the light condition and on the knowledge you had on your camera and lens to obtain a good picture.
Then came lightmeters incorporated in the photo cameras and they became better and better, then came the digital cameras and we could instantly assert if an image was well exposed or not.
How to obtain the perfect exposure? Measure with your camera in different points of the image you wish to take. If the differences are big you may wanna use a light reflector surface or a flash to fill in the darker area/areas. For microstock photography is usually better to overexpose your image by a half stop, or even a full stop, depending on the actual conditions (check Yuri Arcurs' portfolio and see why). Assert the light with your eyes, this is a good exercise for beginners and it's also a way not to forget where we started from as photographers. Use the manual mode of your camera and shoot images with different times and exposures until you achieve the perfect one. You will find this rewarding in the end.
- best natural light you can have is on a cloudy day. Why? Because sunlight refracts through the clouds and the result it a surrounding light just perfect for shooting outside
- light reflecting surfaces such as aluminum foil are great to reflect the sunlight onto your subject's dark side (they are also available at specialized shops but you can build one out of tin foil and cardboard, just stick the foil to the cardboard and you have a light reflector)
- white is your best bet if used as background cause it reflects the light back, thus offering a glow to your subject, black simply absorbs all the photons.
- white is not a great choice for clothing when you shoot outside, it will always look overexposed (we all know how hard it is to see those details of the bride's wedding dress)
- red is the strongest color in bright light, green is the best distinguishable color in dim light
- sunlight can damage your camera sensor for good so try not to shoot directly at it
- if you take a picture on a sunny day always keep the sun at your back, you will have a sky to look at in your pictures and the things and people your shoot will show clear features
- sunset light is great for shooting, thanks to our refracting atmosphere the light will catch a warm glow that will make your images look dreamy
My final advice is, before you go shooting mind the light, cause everything depends on it.