Day 1: The Big Three: Shutter/Aperture/ISO

Welcome to the first post in my 100 days of photography! I am so stoked that you’re here! I am starting with square one for those here who have been recently blessed with their first digital SLR camera! Get ready, cause your life is going to change! There is nothing more exciting than falling in love with a new art form and honing your craft. I wanted to start with “the big three” or, aperture, ISO and shutter; just so as we talk over the next 100 days, you’ve got those terms down.

denise karis photography blog 100 posts in 100 days for photographers

ISO: When I’m choosing the settings for my exposure, ISO is the first thing I set. The ISO determines how sensitive your camera is to the light that comes in. A low ISO, like 100, is the least sensitive to the light. Think of it as wearing super dark sunglasses. A low ISO is going to allow your eyes to be the least sensitive to light. A low ISO will also give your images the least grain (also called noise) and the best color. When there is lots of light, you should be using an ISO of 100 or 200. As we lose our light, maybe it’s a cloudy day or your sun is going down, we boost our ISO to 400, 640, or 800 and beyond. This is increasing our sensitivity to the light that is available. So, the tint on your sunglasses starts to fade and the camera will be able to take photos with less available light. The higher the ISO, the more grain and the more color shift you start to experience, so try to stay low when you can.

Aperture: This is the second setting I choose. This determines two things: The depth of field in an image and how much light is let in as the shutter opens. Think of it like a window. A tiny window in a room will let in a small amount of light while a bigger window will let in more light. Check out the gif below. When the aperture is “wide open” (you’ll hear people saying they shoot wide open) it is a low F stop (aperture value) of 1.2, 2.0, or 2.8, and the depth of field is going to be shallow. For example, if you focus on an eye, their nose or mouth will be slightly out of focus. When you close the aperture down to a higher F stop like 9.0 or higher, then less light gets in and more of the image is in focus. The depth of field gets wider so that if you focus on an eye, their nose, mouth, and ears are all in focus. People like shooting wide open because a blurry background is creatively appealing and it allows for lots of light to come in.


Shutter: This is the setting I change most often. The shutter opens and closes to start and end the taking of the picture. The longer the shutter is open, the more light is allowed to come in. The rule of thumb is to try not to go below twice the value of your lens. So if you’re shooting with a 50mm, try to stay above 1/100th of a second shutter speed. When you go too low on a shutter, you will get motion blur (for a moving subject) or camera shake (as your hand moves when holding the camera). Setting a low shutter speed has its place, but typically a higher value will be used when possible. If you look at your image on the back of your camera and it’s too dark, slow down your shutter to let in more light. If it’s too bright, speed up your shutter to let in less light.

Let those three set in overnight, and tomorrow we will talk about shooting in manual mode!

Denise Karis is an Arizona photographer who enjoys musicals, Doctor Who and breakfast burritos. IG @denisekaris