In the previous article about shooting manual on the DSLR, we went over what we’re trying to achieve with exposure. We also covered ground on what aperture means and how it affects photographs.
Today, we’ll cover the other two aspects that you should be keeping in mind. The interaction between the three elements is what will create the perfect image for you.
In the exposure paragraph I told you that the shutter curtain opens and exposes the sensor, then it closes to shut the light out again. The length of time the shutter remains open is the shutter speed. A faster shutter speed means that the shutter opens and closes quickly.
A shutter speed of 1/8000 means that the shutter stays open for 1/8000th of a second. That’s an incredibly quick shutter speed, and it allows you to capture action shots. I.e. if you wanted to photograph a hummingbird, the fast shutter speed would capture an individual flap of the wings clearly instead of blurring the wings.
High shutter speed produces crisp, blur-free images, but requires a lot of light to get the exposure correctly.
A shutter speed of 30 seconds, on the other hand, is extremely slow and requires a tripod. Any slight movement would blur the image you’re capturing with such a slow shutter speed. Slow shutter is typically used in night-time photography and can capture things like light trails on a highway or the night-time sky when paired with the correct ISO and aperture.
When you’re shooting handheld (without a tripod), the minimum shutter speed should be around 1/30 to still get a crisp image. Anything lower introduces a greater chance of blurring due to any slight movement.
ISO is your sensor sensitivity. It can range anywhere from 100 to 25,000 standard. In particular cameras, it can be extended. For example, the Nikon d810 ISO can be extended up to 51,200. The camera I’m currently using, Sony A7rII can go up to 102,400. Most people don’t need these types of capabilities. Cameras with large sensors tend to have better ISO performance.
So, what do these numbers mean? Traditionally, the ISO refers to film’s sensitivity to light. In this case, it’s the sensor’s sensitivity to light. So, at higher numbers, the sensor is more “sensitive” to light, meaning, more of the light penetrates and burns onto the sensor. A lower ISO is used in brighter light situations. A lower ISO also produces less noise in an image. A higher ISO allows more light in low light situations, but it also comes at the added cost of noise.
How the Three Aspects interact:
There are perfect combos for every photographic situation, taking the three aspects of photography into account. For example, it’s a bright day on the beach. You’ll want to start by adjusting the ISO to something low, like 100. This reduces the intensity of the light entering the sensor. Now, you’ll want to set the aperture (F-stop). You can pump that up to f/16. Now, play with the shutter speed. If we are following the sunny f/16 (you can brush up on it here), well known in photography to meter our the camera in bright conditions, the shutter speed should be set to 1/100.
Those are the basics! In the next article, I’ll go more in-depth into the different shooting modes on your camera and the different settings you might want to start with depending on the shooting situation.