Wurmwood Photography

Fine art, Conceptual, Fashion, Portraits

Understanding Aperture, ISO, and Shutter Speed – The Photographer’s Triangle

For many, shooting in manual mode can seem quite intimidating. It’s really very simple once you get the hang of it, and with practice comes perfection. Here we discuss the three major factors in taking any photo:
Aperture, ISO, and Shutter Speed.


      Aperture is valuable because it is responsible for our depth of field which can either blur a background, or bring everything in frame into focus. Aperture refers to the amount of light that gets into your shutter. When the aperture is wide open, it lets in a lot more light (much like our iris) and it blurs the background. By shooting with a more closed aperture (lower number) it cuts off a lot of light, but keeps everything nice and in focus. Aperture is measured by something called “F stops”. An F stop is a measurement of the diameter of the opening. The larger the number, the smaller the aperture. The numbers are written in decimals, which can also be interpreted in fractions. This is why the larger numbers actually mean a smaller diameter. For example, f/8 = 1/8th which is much smaller than f/4, because f/4= 1/4th. Refer to the chart below. When the circle is cut into 8 slices, the slicers are smaller than when it is only cut into 4 slices. You may remember fractions from middle school, and thinking of the numbers in those terms can help you remember your f stop numbers and what they mean.
The larger the aperture (smaller number), the brighter the image, and less depth of field (blurry background)
The smaller the aperture (larger number), the brighter the image, and a wider depth of field (in focus background)



      ISO stands for International Standards Organization. It is the standardized industry scale for measuring a camera’s sensitivity to light. Simply put, the ISO is the measure of how bright a photo is, with the smallest number being the darkest and the highest number being the lightest. Most cameras don’t go below 100, making the ISO 100 the standard, grain free ISO setting.
When you shoot with a low ISO, you get a nice, “creamy” image. Things that are supposed to be blurred are blurred, and things that are supposed to be crisp are crisp. As you raise your ISO, you make the images brighter but you also introduce noise into your photographs. The higher the ISO, the more noise. This usually isn’t a problem in the lower ranges, between 100 and 400 ISO, but as you get towards 800 or 1200, you’ll start to notice grain. The highest level you can shoot without noise really depends on your camera. Some cameras (such as the Nikon d750) have an excellent ISO range, and are valuable tools with low light photography. This particular camera can shoot upwards to an ISO of around 5800 without any noticeable grain, while a mid-level cameras (Canon t3i/Nikon d3200/etc.) may only be able to go up to 400 or 800 without noticeable grain.

-Less grain.
-Darker Images
-Higher quality

High ISO
-More grain.
-Brighter Images
-Lower quality

Shutter Speed

      Last but not least is shutter speed. It’s almost self-explanatory, but shutter speed refers to the speed in which your shutter closes and captures a picture. The faster your shutter speed, the quicker you can capture an image. Let’s say you’re shooting photos of a man running. You’re going to want a high shutter speed. If you have a low shutter speed, the man would be blurry in the shot. A fast shutter speed, however, would stop motion, and capture a crisp image of the man.
      It’s important to remember that shutter speed deals with light much like ISO and Aperture. The longer your shutter is left open, the more light it is able to capture. That means that higher shutter speeds make for darker images, and longer shutter speeds make brighter images. If you were to take photos of the moon or stars, you would need a very long shutter speed in order to capture all the light in the photo. You can’t light the moon from earth, so you need to leave your shutter open long enough to capture all the light that is already available. Because your shutter speed will be very slow, every small shake or breath you take will move the camera, resulting in a blurry image. If you shoot anything with a long shutter speed, it’s best to use a tripod to hold your camera steady.
      Shutter speeds are measured in fractions as well. This time as fractions of a second (when under a second). For example, ¼ means a quarter of a second, while 1/250 means one two-hundred-and-fiftieth of a second (or four milliseconds). The BULB setting is another shutter speed setting, where the shutter is left open as long as the shutter button is being held.

So, how do they all work together?

      All three are in charge of light, which is the single most important aspect of photography. Lighting can make or break a photo, and these settings help you utilize the most options when lighting a photo. Using a combination of the three settings, you’ll be telling your camera how much light it needs to capture.

Let’s say you are shooting outdoors at dusk, but there’s still plenty of light (or so you think). You are photographing a butterfly that has perched itself on a flower. The butterflies wings are moving slowly as she rests. Because there’s plenty of light, you opt to shoot at an ISO of 100. You know her wings are moving, so you need a shutter speed fast enough to capture her crisply, and not have her wings turn out blurry. So you opt to shot at 1/125th of a second. You want her entire body, the flower, and the ground to be in focus, so you choose a small aperture of f/10. You take the shot, and it’s so dark you can barely see anything but the outline of what should be a bright butterfly. This means you need more light in your shot.

Now let’s pretend you choose to change the shutter speed. If you make the shutter slower, you can capture more light. So you change your shutter speed to 1/20th of a second. You take the photos, and success, it’s bright! However, you’ve now got blurry wings because her wings were moving faster than your shutter. So you know you’ll have to bump that shutter speed back up, and it’s going to get darker when you do. You change your shutter speed to 1/80th of a second, which is pretty fast, but now your image is dark again, albeit less dark than the first photo. So what else can you change?
Next, you decide to change the ISO. You bump your ISO all the way up to 1600, and snap a photo. Now you’ve got a nice bright photo, with sharp wings. The only problem is the grain in the photo is too high, and ruins the quality of the photo. That’s no good, so we’ll turn that ISO back down and leave it around 400. Now you snap a photo and notice that things are much better than the first shot. You can see the ground, the flower, and the butterfly. Everything is in focus, the grain isn’t overwhelming, and the shutter is fast enough to freeze the movement of the butterfly’s wings. But, the photo is still too dark.

 So what’s left to do? Mess with the aperture of course. In order to let more light into the photo, you have to give up some of your depth of field. You raise your aperture to f/5.6 which lets in considerably more light than f/11. You take the shot, and perfect! Your ground I no longer as crisp as it was, but everything is sharp, bright, and how you wanted it. Now, slight changes can be made to the shutter speed, ISO, or aperture to get to your perfect balance.
Now let's pretend it got even darker out, what can you do? Well, as before, you'll need to experiment with your settings. Sometimes it's a simple as decreasing your shutter seed or increasing your aperture. You'll have to experiment to get the perfect shot. 

Shutter speed, Aperture, and ISO work together to tell your camera what to do and how to capture an image. When one takes, another sometimes needs to give. If you want to work with fast shutter speeds in darker areas, you’ll have to have a lower aperture or a high ISO, or a combination of your aperture and ISO being in the middle, to compensate for the lack of light you get with a fast shutter speed. The easiest way to get more light into your shot is to work with manual lights or flashes. You can pick up relatively cheap speed lights and diffusers from Amazon, which can help you bring more light into a scene where you might not otherwise have it. Having more light means that you don’t have to change as many settings to compensate for the lack of light. The more light you have, the more freedoms you have to shoot. With a lot of light, you can have low apertures with fast shutters speeds and lower ISOs. There’s no such thing as too much light, because if you have too much light you can always raise your shutter speed or aperture, giving you even crisper, sharper photos. 

You have to learn how to use the settings in tandem, but with plenty of practice, these settings will start to come more natural to you, and you’ll be able to set up your camera for a variety of situations with short notice, based on your preferences. Learning the triangle of photography is absolutely imperative to taking professional looking photographs, and mastering it will put you well on your way to making a living off photography, or just leveling up your skills.


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