As promised, today’s topic will cover Shutter Speed and Aperture, a couple of fundamentals you should know and fully understand. I would like to also note that this series of blogs is catered towards the beginner and much of it is oversimplified. My purpose here is to remove some of the mystery and maybe help create a clearer understanding of these principles.
As with ISO, these two settings allow you to manipulate your available light and capture the image that you, as an artist, envisioned. ISO, Shutter Speed and Aperture are commonly known as the Exposure Triangle. Here is the Exposure Triangle graphic-
Shutter Speed / Shutter Time
Your shutter sits directly over the sensor in your camera and it’s purpose is to control the period of time a specific amount to light hits the sensor. Shutter Speed is also referred to as Shutter Time, maybe that’ll help some of you understand this principle a little easier. As you see in the graphic, the slower the shutter speed/time, more light and more motion will be present. As you increase the shutter speed/time, you decrease the light and the ability to freeze motion occurs.
Understanding and utilizing your knowledge of shutter speed will dramatically effect the outcome of your vision. For example, let’s say you’ve decided to go out and shoot photos of hummingbirds. Being able to control your camera’s shutter speed will allow you to either use a fast shutter to freeze all movement and get all the details of the hummingbirds wings or slow down the shutter and show movement in the wings. Waterfalls and rivers are another great subject to either stop motion or give a more dramatic look by presenting the appearance of motion. There is no right or wrong, it’s your interpretation. Have fun with this, experiment, try different settings. Unlike learning and experimenting on film, it costs you nothing to take bad shots. You’ll learn as much from the bad shots as you will from the good ones.
We discussed shutter speed in regards to moving subjects but there is one more dimension called camera shake you should be aware of as well. Camera shake will occur when you are using a very slow shutter speed or shooting with a long telephoto lens. While the steadiest of hands might be able to hand hold a shot at a shutter speed of 1/30 sec, I would still recommend using a tripod at that speed or slower. This way you are assured you grabbed the sharpest, cleanest image possible. On telephoto lenses, do yourself a favor and use a tripod on anything longer than 300mm. Again, I am oversimplifying this for the sake of fundamental instruction. Yes, there is a formula to figure out what the minimum shutter speed should be in relation to what lens you are using but I don’t believe it’s pertinent at this time.
The last leg on our discussion of the Exposure Triangle and perhaps the one fundamental that is the most difficult out of the three to fully understand. Aperture, also known as f-stop, refers to the opening inside your lens that lets in light.
The biggest confusion for beginners is understanding that the bigger the f-stop number, the smaller the opening is. As you can see on the illustration above, f/16 is a pinhole when compared to f/2. Each step from one f-stop to the next is called a “stop”. A increase from f/16 to f/11 is 1 Stop, from f/16 to f/8 is 2 Stops, and so on. Each Stop doubles the area of light going to your sensor. Conversely, a 1 Stop decrease cuts the area of light in half. Sounds pretty similar to the ISO settings doesn’t it?
So why not always shoot with the widest opening available? Well, that’s what point and shoot cameras do. They have a fixed aperture at f/5.6, maybe f/8 and all your photos will come out pretty much identical (exposure wise). Being able to effectively adjust the aperture allows you to explore your creativity and control what the final image will look like. Let’s discuss Depth of Field (DoF).
DoF refers to the area in front to and behind your subject that is in focus. Areas with small areas of focus have what is called a shallow depth of field. Areas with a large area of focus have a deep depth of field. By adjusting your aperture, you can control the depth of field in your images.
When would you use a shallow DoF? Well, it’s common in portrait photography, wildlife photography (especially birds), and any other time you want your subject to be the main focus of attention. Use deep DoF on shots such as landscape photography where you want to show as much detail as possible. Take control of your depth of field. Understanding how these adjustments control your it will greatly improve your photography.
I’m going to finish this series with a handy chart that will be helpful as you review the Exposure Triangle. I have just given the very basic explanations of each of these functions and I encourage you to do more research and learn more advanced techniques as you go. The amount to information out there is astonishing. You could spend a lifetime alone watching tutorials on YouTube on just about any topic you are curious about. Most of all, don’t forget to have fun. Don’t be discouraged. Knowledge is truth.