What is Aperture? A Simple Guide for Newborn Photographers
Aperture is the opening inside your lens that controls how much light gets in when you take a photograph. You can control this setting and it is one of the 3 settings, along with shutter speed and ISO, that together control the final look of your image.
Aperture settings are described in f-stops and the numbers are the same across all cameras. You will see values like f1.2, f2.8, f4, f5.6, f6.4 and up to f22 and beyond.
Think of it like your eye. Your eye can squint and let in only a tiny amount of light, or open wide and let light flood in. A high aperture number like f22 is squinting. A low aperture number like f1.2 is opening wide.
What Aperture Setting Should I Use for Newborn Photography
I shoot at f6.4 for my newborn sessions. Many newborn photographers choose a lower number and there are good reasons for this which we will come to in a moment. But f5.6 or f6.4 is a very good starting point and here is why.
Understanding Depth of Field
To understand why photographers choose different aperture settings you need to know a little about depth of field.
When you focus on a point in a photograph everything at that distance from your camera will be sharp. Everything in front of it and behind it will be softer or blurry. You have probably seen portraits where the person is sharp and the background behind them is beautifully blurred. That blurred background effect is created by aperture.
Think of it like standing under a shower. You will get wet. Take a step forwards or backwards and you step out of the stream. Depth of field works in a similar way. There is a strip of sharpness in your image and everything outside that strip becomes progressively softer.
Here is where aperture comes in. A very low f-stop like f1.2 makes that strip of sharpness extremely narrow, like a very thin stream of water. Get it exactly right and only your subject's eyes will be sharp while everything else melts away beautifully. It is a stunning effect when it works.
But if you are not very experienced, if your lens is not perfectly calibrated, or if your baby moves at the last moment, that narrow strip of sharpness will miss your subject entirely and you will simply have a blurry baby. Not the look anyone is going for.
A medium aperture of f4, f5.6 or f6.4 gives you a much more forgiving strip of sharpness. Your baby will be clearly in focus with a still pleasingly soft background. It is the reliable professional result that parents will love and that you can achieve consistently session after session.
Try It on Your iPhone Right Now
If you have an iPhone you can see exactly what aperture does without picking up your camera.
Open your camera app and swipe to portrait mode. At the top of the screen tap 6 white squares and then the f symbol. This will bring up a slider. Move it from one end to the other and watch what happens to the background in your frame. At the lowest number the background will be very blurred. As you increase the number the background will gradually become sharper. That is aperture in action.
Play with it until you can see the difference clearly. Then you will understand exactly what you are controlling when you set your aperture on your camera.
What Aperture to Start With
Set your aperture to f5.6 and shoot from there. You can adjust it as you become more confident and as you understand how it interacts with your other settings. The most important thing at the start is to get sharp, well focused images of your baby clients and f5.6 will give you that reliably.
My Simple Six course covers aperture, shutter speed and ISO together in easy steps so you can see exactly how the 3 settings work with each other to create a beautifully exposed photograph.
If you would like to understand how aperture works alongside shutter speed and ISO, my guide to how all three settings work together is a good place to start.