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Shutter Speed with Candle Lights

A super-geeky fact that I love mentioning during my NYC photography classes is that when you point your camera at a scene, your camera measures the light in that scene and applies a number to the amount of light. You will never see that number since your camera doesn’t show it to you (the number stays embedded in the software of your camera).

Shutter Speed Photography by the Numbers

This number actually represents the number of candles it would take to replicate the amount of light in your scene. If you’re camping in just moonlight, that’s the same as about one candle of light. If you’re in your living room with all the lights turned on, that’s worth 130 candles worth of light. If you’re in a bright office building, that’s about 180 candles worth. Now, get this: If you’re taking a picture of something that is directly lit by the sun, that is the same as 130,000 to 180,000 candles worth of light. Isn’t it phenomenal that your camera can operate in such a wide variety of lighting conditions?

We take for granted that we can take our camera onto a sunlit beach and our camera knows exactly what to do. We can take that same camera into a candlelit restaurant and our cameras know what to do. And, yet, on the sunlit beach, there is 2,000 times the amount of light relative to the candlelit restaurant. How does a camera deal with this massively wide range of lighting conditions?

How Shutter Speed Photography Works

This is done primarily with the shutter speed range of the camera. The range on a high-end digital SLR spans from 1/8000 of a second to 30 full seconds. Imagine how much light comes in when you have your shutter open for 1/8000th of a second. Now, imagine if you leave your shutter open for 30 seconds. Can you start to grasp what a massively huge difference the shutter speed is?

Hence, shutter speeds around 1/8000th of a second works for direct sunlight. Shutter speeds of around 30 seconds works for nighttime shots.

George Eastman, founder of Kodak, has a quote that I love: “Embrace light. Admire it. Love it. Above all, know light. Know it for all you are worth and you will know the key to photography.” My first photography teacher told me, on the first day of classes, “Photography is light.” I remember sitting there being so confused by that statement. What did she mean? It took me some time before I fully understood it. But it’s really intuitive: If you don’t have light, you can’t create an image. Light is the medium. Shutter speed is the answer.

The amount of light from a candle isn’t the only fire-related influence on how your camera works. The color of fire is the measure of a camera’s white balance settings. I’ll save explaining white balance for another blog post, but the brief version is that white balance has to do with the colorcasts of different light sources. Those colors mostly range from orange to blue. As you probably know, fire goes from orange to blue as it gets hotter. If you have a camera that allows you to choose a specific number for your white balance (in addition to the standard options of sun, cloudy, shade, fluorescent, flash, etc.), then your camera is asking you to choose a number that corresponds with the temperature of fire when it gets to that particular color. The higher the number, the more blue the color cast of light you’re choosing for the camera to compensate against.

As you dive deeper and deeper into shutter speed and how your camera works, you see that it really is all about the light. Turns out my first photography teacher knew what she was talking about.

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