Learn EXPOSURE easily — ISO, Aperture & Shutter Speed

What is ISO, aperture and shutter speed? And most important: how should you use them to make nice photos?

When I started photography, I didn't know what to learn first. I took my camera, tried to snap a photo and that's what it took me to start to understand what I had to learn. So if you're at this point, I strongly recommend you read this article (or watch the video) and do that!

What is exposure?

Exposure is the amount of LIGHT that reaches your camera sensor.

There are three elements that influence and therefore, are able to change, the exposure: ISO, aperture and shutter speed.

Increasing or lowering these items changes the amount of light that comes into your sensor and therefore, makes your pictures lighter or darker. Each of them have their own particularities as you will see below.

ISO

This is the first thing I check in my camera before I start shooting a session, an event or a product is the ISO.

The lower the ISO you’re using, the more light you will get in your photo.

The lower you keep your ISO, the less grain/noise you’ll get in the photo. So if I’m shooting outdoors during the day, I usually have my ISO set to 100 or 200 maximum.

Then if you go indoors, you’ll realize that even if you change the other settings we will talk about in a minute, you might still need to increase your ISO so your photo won’t be too dark. I use a Canon 5D Mark IV and if I use the ISO up to 800, I see nearly no grain at all. Up to 1600, there’s a little bit of grain, but only if I really pay attention to it.

From 3200 up, it starts to bother, but still acceptable.

But, for many newer cameras, you can use the ISO up to 16.000 and it might still look great. So the tip I have for you is: make a test with your camera.

Shoot a photo with each ISO and see how it changes while you increase it. Then you’ll also see what you believe is the limit.

I try not to use my ISO higher than 3200, so unless I have no choice, I don’t use it higher than that.

On the other hand, some people like the grainy effect to their photos. Actually, some people even add them in post production. So, again, try it out and see what’s acceptable for you.

APERTURE

The aperture is the second element in the exposure triangle.

It is the opening in a lens through which the light passes to enter the camera. Complicated?

Let’s make it simple:

Do you know the numbers photographers talk much about when they mention lenses? “This is a 50mm f/1.8. This is a 16–35mm f/2.8…” and so on? The f/1.8 or f/2.8 refer to the aperture.

When you read “f/1.8”, it means the lens opens up to f/1.8 to receive light. The lower the number, the most light it is able to receive. A f/1.8 can receive more light than a f/2.8. So with a f/1.8 lens you can make brighter pictures than with a f/2.8, you can make pictures in darker places, without losing quality. With a f/1.4, you can get even better pictures in even darker places. And so on.

It is important to say that if you buy a f/1.8, for example, the f/1.8 is as bright as the lens gets, but of course you can settle your camera to make the lens receive less light if you want. The number you see on the specification of the lens is just the maximum aperture of the lens, but you can use a f/1.8 in f/2.8 or f/3.5, f/5.6 aperture and so on. You just have to settle it in your camera.

"And how do I find the aperture when I’m playing with my camera?" Different cameras have different ways of adjusting the aperture, but play around with it and search for the F when adjusting the settings.

It is also important to say that the APERTURE will affect your depth of field.

The higher the aperture, or, in other words, the lower the number, the greater the depth of field you will have.

In terms of results, what this means is, if you shoot with a wide open aperture, in f/1.8 or f/1.4, for example, and you have four people in different depths of the photo, you should know you will probably be able to focus in only one of them, specially if you’re close to one of them. That happens because your aperture is very narrow when you use a wide open aperture. For that reason, when I take group photos I always try to use f/2.8 or lower aperture. And remember, when I say lower aperture, I mean higher number. For two people, I usually use around f/2.8; for more people, I go with around f/3.5.

SHUTTER SPEED

This is the third element that will affect your exposure.

The shutter speed is the length of time the camera shutter is open, exposing light onto the camera sensor. The faster the shutter speed, the shorter the time the image sensor is exposed to light; the slower the shutter speed, the longer the time the image sensor is exposed to light.

If you shoot a subject that is moving, you will get different results in different shutter speeds.

If you want to freeze motion, you should increase your shutter speed. If you want to catch the movement on photo, decrease it.

So, for example, if I’m shooting portraits, in my camera, I’m usually comfortable with a 200 or higher shutter speed. If I shoot portraits at 1/100 shutter speed, my images might not be sharp enough. You know when you take those photos that look a little blurry? That’s what might happen if you use lower shutter speeds. So if I want to shoot a portrait with 1/100, I maybe should use a tripod because then I won’t move the camera when I shoot and will able to do a sharp image anyway.

If I want to show movement in the photo, then I need to decrease my shutter speed.

So you might be wondering: "if I just settle one of them, I’ll get the good light, right? Why should I care to all of them?"

This is the art to it! And this is where practice makes perfection! There will be situations in which you’ll have to make choices, specially — but definitely not only — with non-professional or older cameras. Maybe you want to take the photo of a ring, for example: you get your macro lens, you are really close to the ring and to get it all in focus, you need to have a lower aperture. Maybe f/7, maybe f/11. But when you do that, you will notice that the picture might be very dark since there is less light coming through the lens. To compensate that you will have to change the ISO and the shutter speed. You will need a higher ISO, maybe 800, 1000 — test the limits of your camera — and if the limit for you to take that photo without grain is 1000 ISO, for example, and the photo is still dark, then you would need to compensate with the shutter speed. You will need a lower shutter speed. And on that case, if you go under 1/160 or 1/100, unless your hands are really steady, you might not get it sharp. The photo might start being a little bit blurry. So you will have to use a tripod and shoot it at 1/60, 1/50, 1/40.

SETTINGS TO HELP YOU TO START OUT

Please have in mind these are settings that work for me with my camera. But if you want, you can start with these settings and adapt it according to your exact light situation, personal taste, camera and lenses also.

If I set my camera for a cloudy day, outdoors, portrait photos, I’d start with:

ISO: 100 ISO / Aperture: f/1.8 to f/2.8 / Shutter Speed: 1/320 or higher

If I set my camera for indoors, an event or wedding:

ISO: 800 ISO or higher / Aperture: f/1.8 to f/2.8 / Shutter Speed: 1/200 or lower and if I went lower than 1/160, I wouldn’t breathe when taking the photo, so it would be sharp.

Ideal: I would have a flash with me and change my settings a bit, but this might be a topic for a next talk.