Low Light Decorations

Low Light. Just about any camera or lens combination will produce a good picture in bright sunlight. But what about low light? That is where the combination of a good camera body and a large aperture lens is the best choice.

Three ways to increase the light, OK – maybe four…

There are three main ways to create an image when you are confronted with low light. All of these have trade offs and compromises.

The first option is to increase the ISO setting of your sensor. Increasing the ISO will give a brighter image but will also create a lot of noise (random spots and colors) in your image. Why? Digital sensors achieve higher light sensitivity by increasing the voltage on the sensor. Higher voltage gives more noise. Try turning on a stereo and crank up the volume when nothing is playing. You will hear a loud hiss or hum and that is noise!

The second way to deal with low light is to slow your shutter speed. Changing from a 1/60 second to a 1/30 second doubles the light hitting your sensor. The trade off here is image blur. The slower your shutter speed the more likely you are to get a blurry image. One reason is you may move the camera slightly while the shutter is open. The other reason is something in your picture may move. You can use an imaged stabilized lens or a tripod to reduce camera shake. Not much you can do to stop the world from moving.

The third option is to use a more open aperture. Going from f/4 to f/2.8 doubles the light hitting your sensor. Below is a chart showing light doubling apertures – steps that double (or cut in 1/2) the light. So If I am using an f/4 lens and I go to an f/1 lens I get 2x2x2x2 more light or 16 times more light hitting my sensor! An f/1.2 lens gives more than 10 times the light of an f/4 lens. The tradeoffs are large aperture lenses are expensive, heavy (lots of glass) and give a shallower depth of field.