Tips + Techniques

Aperture and Depth-of-Field: How to Break the Rules

March 18, 2021

By Si Moore

© Bayly & Moore

Shapes and leading lines that shout when they’re in-focus can be softened to a whisper with an appropriate aperture. Captured on a Canon 5D Mark IV at 50mm, f/2.8 and 1/6400 sec.

Si Moore is one half of Bayly & Moore, a wedding and portrait photography duo based in New Zealand named Rangefinder 30 Rising Stars of Wedding Photography in 2014. In this series, he cracks open basic elements of photography—like aperture and depth-of-field—to get to the bottom of how to experiment with them. Check out his most recent piece: The Rule of Thirds—How to Use It and When to Break It.

It turns out that if you really want to master your craft and shake things up, you need to start at the beginning. So here we are at the very start, talking about how to master your aperture: the hole that lets all the magic storytelling stardust light into your capturing machine. 

For those who came in late, the Italian word for “room” is camera, for “opening” is apertura, and for “window” is finestra. So if your camera is a dark little room, then the opening where the light comes through is the aperture, and the way we refer to its various levels of opening is as an f-stop—from finestra. That’s pretty much the end of it, but it’s also barely the start. 


aperture and depth-of-field can communicate the feeling of a place as in this wedding by bayly & moore.
Use aperture variation to communicate the feeling and experience of being in a place. Captured on a Canon 5D Mark IV at 50mm, f/2.8 and 1/800 sec. All photos © Bayly & Moore

Forgive me for shooting straight and simple for a moment, but aperture is pretty much…a hole. Your lens (or sometimes your camera) has an adjustable hole in it made up of overlapping blades of metal that compress or expand to give you whatever aperture setting you select.

Small f-stop number = big hole = lots of light = very shallow focus.

Big f-stop number = small hole = not much light = very deep focus.

A lower aperture number means a larger hole, and a higher aperture number means a smaller hole—yeah, you heard that right. So f/1.2 (remember, f is from finestra, which means “window”) is a huge hole that lets in loads of light and by the magic of physics, it gives you a very shallow depth-of-field—a very small slice of focus. Meanwhile, f/22 is down at the other end of the game, giving you a very small hole that lets in hardly any light, and gives you a very deep depth-of-field—everything’s in focus from here to Mars.

[Read: How to Separate Portrait Subjects From the Background]

Now, we could get neck deep in physics here around how the size of the hole translates to depth-of-field, how the size of the sensor or film dramatically affects the shallowness, how the shallowness decreases the farther your subject is from your lens, and how those lens blades create different artifacts and shapes of bokeh. But we’re all about the basics, so let’s figure out how to use aperture and depth-of-field as a tool and we’ll see if the rest takes care of itself.


how to use aperture by layering the story inside shapes in couples portrait session with si moore.
Using layers inside shapes doubles the power of your compositions. Captured on a Canon 5D Mark IV at 35mm, f/3.2 and 1/125 sec.

Alright my friends, in the grand game of using your gear to open up more creative options, there is no greater player than aperture. As it turns out, there’s a whole lot more going on here than simply acquiring light-gathering horsepower for dark situations. It’s called depth-of-field.

In buying our first few lenses, most of us realize very quickly that the smaller the number, the “faster” the lens, the more desirable the result (so we’re told), which ultimately equals the more money we have to pay. And once you’ve paid that fat cash for that fast lens, you’re sure as hell going to use it as fast as it can possibly go (kind of like a teenager and their first motorcycle). For the next year, you’re shooting everything on f/1.2, feeling like you’re living in a dreamland but also realizing it’s not the magic bullet you hoped for. 

[Read: Balancing Work and Play to Find Your Creative Style in Photography]

As it turns out, faster and shallower is not always better, and figuring out how to use an appropriate depth-of-field to tell the story that’s in front of you is one of the key equipment-focused skills you can develop.

Here are a few examples to get your brain ticking:

1. Create layers by isolating or adding context.

example of using layers of a wedding story.
Look for story layers in candid moments to introduce more characters. Captured on a Canon 5D Mark IV at 35mm, f/2.8 and 1/3200 sec.

When you’re faced with a busy scene and you want to slice a key character out of the action, a shallow depth-of-field (an aperture setting of f/2, for example) will help you instantly make them “pop.” The late conflict photographer Tim Hetherington was the absolute master of this, using out-of-focus foreground layers and shallow depth-of-field to find poignancy and stillness in chaotic war scenes.

Likewise, you can head in the other direction and put a character in absolute context by shooting for a result that puts everything in the frame in sharp focus. Steven Shore, ever the f/22 master, uses this device over and over to give your eyes an absolute feast while using leading lines to let you unlock the story. Rather than focus and layers being a tool, he utilizes geometry and carefully constructed frame divisions.

The thing to remember here is that we’re talking about two very different ways of telling stories, and each of these genius artists is using aperture and depth-of-field as a tool to do things their way. There are no magic bullets or absolute rules of thumb, but there are fresh and different ways of seeing.

[Read: 9 Things You Need To Develop a Signature Photography Style & Aesthetic]

Take that tired old descriptive trope of calling an image “cinematic.” As still photographers, we often reference cinema and are looking for a result that looks similar to how films feel for us, so we go and shoot at the fastest aperture we can and find that we’re actually killing the story, not assisting it. For most features, directors of photography are shooting somewhere between f/4 and f/8—most likely a f/4 to f/5.6 split—which is a long way off the beloved wide-open aperture of still photographers.

So why are we obsessed with that look? Sometimes we’re looking for fast visual home-runs and easy rules to abide by rather than slower, more well-constructed context. More often than not, those dreamy, magic, out-of-focus shapes that we’re creating in the background and foreground as we separate a character out with shallow depth-of-field are just distracting for the audience to view. They lose the context and they distance the character from the story they’re a part of.

But then, sometimes they’re just magic AF. So hey, follow your heart and find your natural mode of communicating what’s going on in a scene. Use aperture and depth-of-field as one of your many tools to communicate with your audience.

2. Make the light feel dreamy or make it feel clinical.

couples portrait session focusing on what subjects see
Focus on what your characters are seeing to tell the story through their eyes. Captured on a Canon 5D Mark IV at 50mm, f/2.8 and 1/1250 sec.

Okay, here’s a touch of sorcery for you. The angle the light enters the barrel of your lens has a lot to do with how many artifacts it creates along the way—all the glory stuff like lens flares, colorful reflections of the coatings on the elements of your lenses, weird and wonderful bounce. All of the things. I mean, we’re talking about starlight that’s travelled nearly 100 million miles across the galaxy in 8 minutes, here. It’s magic stuff, it’s unpredictable and wild, and it does beautiful things when it hits all of the glass in your lens and makes its way through that hole to your camera. It’s quite a ride. And when that hole is as big as it can go, you’re making its job a whole lot easier.

But there are also plenty of times where you need to tone down the glory and bring a sense of focus to how you’re using the light. Crazy magic might seem like a good idea all the time, but everything has its time and place.

Rather than get into physics here (the circle of confusion is quite confusing), just try this: Go shoot a street scene in glorious sunset light with your lens wide open (as in, as fast as it goes—f/1.2 would be a good place to start). Swing that lens around until you hit absolute wild glory. It’ll probably be a little backlit, definitely with some lens flare magic. Now shoot the same scene on f/16 (obviously compensating in your exposure for the sudden lack of light). You’ll notice a major difference, and it doesn’t matter how I describe it; what matters is how you understand that difference as a key tool in your arsenal of solving problems and telling visual stories.

3. Nail focus and achieve a classic look.

bride and groom photographed with aperture to add complexity.
Depth-of-field gives you an ability to add complexity and a “look again” feeling to images. Captured on a Canon 5D Mark IV at 35mm, f/2.8 and 1/4000 sec.

Whether you know it or not, you’re hugely influenced by the fleet of groundbreaking photographers who pushed out the boat on our craft in the 1960’s. All of them were shooting on film, and most of them were metering by eye using the very simple “Sunny 16” rule. For a huge amount of the work that we all admire from that period, f/16 was the starting point, with everything in focus. It’s also one of the key tools in a street photographer’s bag of tricks to let them hit critical focus. 

Think of it like this: You’re Garry Winogrand roaming the streets of Manhattan with a 50mm lens on a 35mm film camera trying to focus quickly on a subject 10 feet away in a busy avenue, all while trying to stay cool, keep it subtle and make some magic. At f/16, you have a slice of “in focus” that’s 17 feet deep, but at f/2.8 you’ve got barely 2 feet to work with. You can start to see the attraction of mastering the smaller aperture, the deeper focus, and the brilliance of adding “everything in focus” as a tool for your photography arsenal.


example of how to use aperture and depth-of-field in difficult light situations at a wedding.
Depth-of-field can render difficult light and situations into usable textures. Captured on a Canon 5D Mark IV at 50mm, f2.8 and 1/640 sec.

Most of us have a couple of aperture settings that we rarely venture from. Try a few of these tips and exercises to break down your habits and put them back together with a wider appreciation for what’s possible.

1. Go old school. 

Trust me, you don’t need to be an indie kid to go shoot a roll of film. Hit your friends up and borrow an old banger of a 35mm film camera. A Pentax K1000 would be perfect. The more beat up, the better. The meter won’t work, guaranteed. Put a roll of Kodak’s finest in it, and you’re about to learn the Sunny 16 rule.

[Read: Davis Ayer and the Magic Behind His Masterful Photo Manipulation]

It goes like this: in full hard sun, with your aperture set to f/16, your shutter speed is the same as your film speed (or at least close). Lock those settings in and then head outside and look for action in the full sun.

You’ve just experienced the joy of knowing that everything on your roll is going to be in focus. It’s strangely intoxicating. You’ll also discover that, as focus layers are suddenly out of play, shapes and lines become key compositional tools to embrace.

2. Limit yourself. 

Roll the dice and shoot your next session using what filmmakers call the aperture of the gods: glorious f/8.

There’s something about f/8 where you can get an out-of-focus layer if you really try, but you’ve still got big slices of focus to work with. You can put big movements into that focus window to get an interesting result. If you want something in the foreground to be out of focus at f/8, you need to get right up against it, but the pay off is that everything around your subject is sharp and crystal clear.

There’s a normalcy to it that’s just brilliant and feels a lot more human, a lot more real. If you’ve been shooting everything wide open up until now, f/8 is going to scare the pants off you. You’ll love it.

3. Practice layering. 

Grab some friends, head to the park or your dining room table or wherever, and set up some layers of humans to shoot through. Start shallow, say f/2.8, and work your way back to f/16. Keep moving around to work each aperture and depth-of-field setting until you find a sweet spot that gives you beautiful layers, the right level of separation and context, and supports your central character perfectly. You’ll be surprised by where you end up.


At photography’s most basic level, the way light gets into the camera is going to make or break you, especially when it comes to creating key compositional tools like focus layers. Reassessing your aperture and depth-of-field habits will open up a whole new world of seeing that’ll bring fresh depth to your storytelling. Get out there and rule it.