How to focus with wide aperture lenses

Are you struggling getting sharp photos when shooting wide open?

There are several reasons you might choose to take photos with your aperture open as far as it will go, or as it’s affectionately referred to in the photography world, “shooting wide open.” One trademark of a professional portrait is that nice creamy, smooth background that makes your subject seem to pop off the backdrop of your image, or bokeh. One way to achieve this type of bokeh is to shoot with your aperture wide open. Or maybe you’re shooting in a situation where there is not a lot of light, and you need your aperture wide open to get enough light required for a good shot. Whatever your reason is, achieving a sharp photo when shooting wide open is not always easy, and requires skill and practice. These tips will help you understand how to shoot wide open and still get the sharp photos you’re looking for.

Understand Focal Planes and Depth of Field

A focal plane is the plane through the focus perpendicular to the axis of a mirror or lens, where your sharpest focus is attained. Your focal plane will run parallel to your camera’s sensor. In this image below, you can identify the focal plane by the flowers that are in focus. The flowers that are on the same plane as my focal point (the girl) are in focus, while any flowers to her right or left are out of focus.

How to focus with wide aperture lenses

Your depth of field is the range of distances at which your focus is acceptably sharp. This is essentially how deep or how narrow your focal plane is. When shooting wide open, your depth of field is very shallow, so you will want to have all of your subjects on the same plane to ensure everyone is in focus. In the image below, you can see that the boy on the right is very slightly out of focus. He was standing ever so slightly closer to the camera than the girl, who is tack sharp. Had he been one step to his right, he would have been sharp, too.

How to focus with wide aperture lenses

In the image below, their faces are on the same focal plane, and both are sharp. This image was shot wide open at f/2.0 with a Canon 135L lens.

How to focus with wide aperture lenses

Choose Your Own Focus Point

A general rule for getting sharp photos when shooting wide open is to ensure you are selecting your own focus point (instead of letting the camera choose the focus point for you), and this is especially true when shooting wide open. When shooting at a wide open aperture, it is best to toggle your focus point to exactly where you want it, and not to focus and recompose. In many circumstances, focusing and recomposing is fine, but when you are working with such a narrow depth of field, moving your camera after selecting your focal point introduces even more risk of missing focus. The movement of your camera even a hair off the original focal plane can cause you to miss your focus entirely. When choosing your focal point, focus on the eye that is closest to camera.

Be Steady

Once you have set your focus point, you don’t want your camera to move at all. Your depth of field is so shallow when shooting wide open, that even taking a breath could change your focal plane. Be sure you are anchored well! Try leaning on a wall or nearby structure, taking a wide stance with your legs for stability, and anchoring your elbows at your sides. I even hold my breath when releasing the shutter.

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How to focus with wide aperture lenses

Distance From the Subject

Your distance from your subject plays a role in your depth of field, which you can use to your advantage when shooting wide open. The closer you are standing to your subject the less depth of field you will have. The further you are from them, the more depth of field there will be. Use a longer lens to be able to shoot from farther away and still achieve the effects of that shallow depth of field.

Click Here to read more about How to Get a Shallow Depth of Field!

Practice, Practice, Practice!

As with any skill, it just takes a lot of practice to get consistent and comfortable shooting wide open. Get your camera out and work at it! Learn the nuances of your specific lenses, experiment with shooting wide open from various distances, and practice poses that place your subjects on the same focal plane.

I will admit it: I am a wide open junkie. When I am shooting personal photos or in low-pressure situations, I tend to shoot with my aperture as wide open as it can get. I love the isolation of my subjects and the creamy bokeh I can achieve when opening up my aperture as wide as it will go, AND I crave the technical challenge of nailing a sharp image with such a narrow focal plane. But, there are times when I simply do not want to risk the chance of missing focus on an important shot. Sometimes, the risk just isn’t worth it.

Keep in mind that how each photographer shoots and the settings they prefer are just that: preferences. There is no “right way.” I love to shoot wide open, but there are times when shooting wide open simply isn’t the best idea. It’s also helpful to really get to know your gear. Every lens has a “sweet spot,” or an aperture at which it tends to have the sharpest focus, and this is usually a couple stops above it’s wide open aperture. Experiment with your gear to find out what works best for you!

Do you love to shoot wide open like I do? What have been some of your biggest obstacles to getting a sharp photo when shooting wide open? Let us know in the comments below!

In this section we’re going to discuss several crucial elements for exercising greater creative control over your final photographic image.

Other than lighting, composition and focus (which includes depth of field) are the main elements that you can exercise complete command over.

Focus enables you to isolate a subject and specifically draw the viewer’s eye to exactly where you want it.

The first thing to understand about focus is depth of field.

Depth of Field

How to focus with wide aperture lenses

The depth of field (DOF) is the front-to-back zone of a photograph in which the image is razor sharp.

As soon as an object (person, thing) falls out of this range, it begins to lose focus at an accelerating degree the farther out of the zone it falls; e.g., closer to the lens or deeper into the background. With any DOF zone, there is a Point of Optimum focus in which the object is most sharp.

There are two ways to describe the qualities of depth of field – shallow DOF or deep DOF. Shallow is when the included focus range is very narrow, a few inches to several feet. Deep is when the included range is a couple of yards to infinity. In both cases DOF is measured in front of the focus point and behind the focus point.

DOF is determined by three factors – aperture size, distance from the lens, and the focal length of the lens.

Let’s look at how each one works.

Aperture

How to focus with wide aperture lenses

The aperture is the opening at the rear of the lens that determines how much light travels through the lens and falls on the image sensor.

The size of the aperture’s opening is measured in f-stops – one of two sets of numbers on the lens barrel (the other being the focusing distance).

The f-stops work as inverse values, such that a small f/number (say f/2.8) corresponds to a larger or wider aperture size, which results in a shallow depth of field; conversely a large f/number (say f/16) results in a smaller or narrower aperture size and therefore a deeper depth of field.

Small vs Large Aperture

How to focus with wide aperture lenses

Manipulating the aperture is the easiest and most often utilized means to adjust Depth of Field.

To achieve a deep, rich and expansive DOF, you’ll want to set the f-stop to around f/11 or higher. You may have seen this principle demonstrated when you look at photos taken outside during the brightest time of the day. In such a case, the camera is typically set at f/16 or higher (that Sunny 16 Rule) and the Depth of Field is quite deep – perhaps several yards in front of and nearly to infinity beyond the exact focus point.

Let’s take a look at these two photos as examples. The left side of the photo has an expansive DOF, most likely shot around noon (notice the short, but strong shadows), with an f/22 aperture. The right side of the photo has an extremely shallow DOF; probably an f/2.8 aperture setting.

However, to achieve an identical proper exposure, the shutter speed is probably closer to 1/1000th to compensate for the increased amount of light entering the lens at f/2.8.

Aperture Range

How to focus with wide aperture lenses

The aperture range identifies the widest to smallest range of lens openings, i.e., f/1.4 (on a super-fast lens) to f/32, with incremental “stops” in between (f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, and f/22).

Each f-number is represents one “stop” of light, a stop is a mathematical equation (which is the focal length of the lens divided by the diameter of the aperture opening) that determines how much light that enters the lens regardless of the length of the lens. Such that an f/4 on a 50mm has smaller opening than an f/4 on a 200mm, but an equivalent amount of light travels through both lenses to reach the image sensor thus providing the same exposure.

Each movement up the range (say f/2 to f.2.8) reduces the amount of light by one-half, and each movement down the range (say f/11 to f/8) doubles the amount of light passing through the lens.

It’s important to understand this concept and how it affects exposure because it works in tandem with the shutter speed (we’ll discuss this in another section) to establish a given exposure value.

Basically, when you change the aperture size one stop, you have to shift the shutter speed one stop in the opposite direction to maintain a consistent exposure… and this change in aperture alters the depth of field (DOF) accordingly.

Distance from the Lens

The last element affecting depth of field is the distance of the subject from the lens – you can adjust the DOF by changing that distance.

For example, the closer an object is to the lens (and the focus is set on that object) the shallower the DOF. Conversely, the reverse is true – the farther away an object is and focused on, the deeper the DOF. Changing the distance to subject is the least practical way to manipulate the depth of field, and by changing the distance from a subject to the lens, you immediately change your image’s composition. To maintain the compositional integrity of the shot, but still have the change in DOF from a distance, you can change the focal length (either by changing lenses or zooming in).

Why does changing the focal length negate the effects on DOF? This is because the visual properties of a given lens either provide either greater DOF (shorter lenses) or shallower DOF (longer lenses). The physical properties of a lens at a given focal length also affect the depth of field. A shorter focal length lens (say 27mm) focused at 5 meters, set at f/4 has a deeper DOF (perhaps from 3 meters in front and 20 meters behind) than a longer focal length (say 300mm), also set at f/4 focused at 5 meters. The 300mm lens has a remarkably shallow depth of field.

Incidentally, to help you with this, every lens has a manual with a DOF chart for each f/stop and the major focusing distances. DOF is just a matter of physics, and it’s important to grasp this concept.

Conclusion

Manipulation of depth of field is a good way to modify the characteristics of your photo, and manipulating the aperture is the ideal way to do this because it has little or no effect on composition.

You simply need to change the shutter speed (or change the light sensitivity – ISO) to compensate for the changes in the exposure from the adjustments to the f-number. Changes in distance and focal length also affect DOF, but these changes have trade-offs in terms of composition.

Therefore, changes to aperture are the best way to manipulate DOF without affecting a photo’s composition.

We’re focusing on focusing this month. How do I focus my photos is one of the most asked questions of me by other photographers. It’s a great question, and one that one would think would be pretty basic and simple. It’s usually the last skill that a beginning photographer considers when starting out but seems to be the toughest to master. I mean it seems that it would be pretty basic, what with the sophistication of the Auto Focus features in modern digital cameras, but once one takes a few photos and is let down by the Auto Focus Mode it’s easy to see why in many cases, especially landscape and portraiture, you will want to manually focus your photo.

There are several things that will affect the focus or clarity of our photos including a completely out of focus image, one where the focus is so far off that nothing is clear or in focus. That issue is obvious, of course, so we won’t discuss this in depth. We will assume that we are focusing but want to refine the clarity and focus of the shot. I’m going to try to proceed without citing mathematics or terms and theories such as Hyperfocal Distance, Circle of Confusion etc. The purpose of this article is to just understand the basics enough to understand how to overcome a common problem with focusing. Trust that this could become so lengthy that it would require another ten pages of the Mountain Times to cover it. Sometimes when someone is learning something new more information beyond what it takes to understand the concept causes confusion and discouragement. Once the basics are learned the understanding can be broadened in the future. I always tell people that if it requires mathematics to take photos I’d be a C-Minus photographer.

First let’s consider blurring caused by the camera moving or objects in the scene moving. This is not a focus issue but it can affect the clarity and areas of focus in the photo as you affect it. If movement is causing problems then your shutter speed is too slow. You’ll need to make sure that your shutter speed is sufficiently fast to freeze the movement. There are times where a slow shutter blur effect is desirable such as in creeks or waterfalls. This typically requires one to make an aperture adjustment to vary the shutter speed. Opened more to make it quicker and closed more to make it slower, but the depth of field will change with each aperture change.

So what’s this depth of field of which you speak you ask? The depth of field is how deep the area that will be in focus is from front to back. The wider your aperture the shallower or narrower your depth of field will be and then when you stop down, or close the aperture down, the depth of field becomes deeper. Remember that the larger the aperture opening the smaller the f/stop number and the smaller the aperture opening is the larger the f/stop number. Something to consider when you’re trying to maximize your focus is that the closer you are to the subject or foreground narrower your depth of field will be as well. If you’re having trouble getting everything in the scene within acceptable focus stand back a little. The same with portraiture. If you’re shooting with a wide aperture to blur the background intentionally you may have trouble getting the person’s whole face in focus. There’s not a lot worse in portrait photography than having the eyes in focus but the nose out of focus or vice-versa. Either stop down (close down the aperture) or stand back a little further or both. This works best with a zoom lens so you can recompose as you move away.

Hyperfocal Distance – I know. I said that I was going to try not to mention this but I think that curiosity will eventually lead a photographer to wonder. Simply and basically, the hyperfocal distance is the point where you will focus to allow everything from the foreground to the background to be in “acceptable focus”.

There’s a mystical mathematical formula to determine what that the hyperfocal distance is, but if you remember this advice you will get by like I have been for a long time without taking a calculator into the field with me. Here goes – I remember that I want to be in my lens’s sweet spot, which is the upper and lower limit of the aperture’s clearest settings. Each lens is different but the average lens is approximately f/8 to f/14. Compose your shot but try not to get too close to the foreground unless you don’t mind the background to be soft – Remember the closer to your foreground the less likely the object in the background will be in focus – And then focus to infinity on your lens focus ring and then focus back until the foreground just comes into focus. Then you will usually have the depth of field maximised and pushed out as far as possible while still maintaining a focused foreground. It’s easy to understand once you try it.

That may have been a long road to a short conclusion but just a basic understanding of how your aperture and depth of field affects focus allows you to take control of exactly how you will focus your photo. I hope that I made that as clear as possible.

Camera lenses work like your eyes; they can adjust how open or closed they are to let in more or less light. The aperture (also called f-stop) is how open or closed your lens is. A wide aperture means your lens is more open, letting more light reach the sensor.

It might seem backwards, but a low f-stop actually means a wider aperture. For example, f/2 is a wide aperture, while f/13 is a narrow aperture.

Typically, anything under (wider than) f/2.8 is considered a wide aperture, but it depends on your lens. Some lenses can’t go that low. In that case, whatever your lens’s lowest aperture setting is a wide aperture.

Benefits of using a wide aperture.

Wide aperture offers a few benefits to help you boost your photography skills:

  • Low-light photography — A wider aperture lets more light reach your camera’s sensor. If you’re shooting in low-light environments, using a low aperture will help you maintain a fast shutter speed to avoid motion blur in your photos.
  • Shallow depth of field — Wide aperture also creates a shallow depth of field, which means your subject is in focus but the background is blurry. It adds depth to your portraits, and can also help with special photographic techniques such as the unique bokeh effect.

Unless you’re shooting a wide-angle shot like a landscape or group portrait, most photographers prefer to use a wide aperture to add more depth to their single-subject photos.

Explore what more you can do with Adobe Lightroom to take your wide-aperture photos to the next level.

I have got an old lens (f1.4) that I have to use only with manual focus on a DSLR. Well, it is difficult for me to get the subject on focus. Although on focus according to the viewfinder, the actual picture is blurred or the focus is slightly elsewhere. I usually reduce the aperture to avoid this. Do you have any suggestions?

Added: I’m using a Pentax K10D.

13 Answers 13

Check if your viewfinder has a dioptric adjustment knob – this is a little adjustment on the viewfinder that allows you to adjust for your eyes. It might be set for someone short sighted.

If it is there then make sure the in-viewfinder display is visible, and adjust so that the display is sharp. Then try focusing on other things.

You could also see if there are alternative focusing screens available for your camera. I replaced the focusing screen in my Canon 40D and it made a big difference in manual focusing. The higher end cameras generally have official alternative focusing screens available, but you could also go to http://www.focusingscreen.com/ or http://www.katzeyeoptics.com/ and see what they have to offer.

You should also be aware that some alternative focusing screens are intended for fast lenses – say f/2.8 or faster.

You’ll have a hard time focussing a wide aperture lens wide open without a live preview with magnifying option. Here’s why:

  • Your viewfinder has a fixed depth of field that you perceive when viewing through it. It’s the matte screen that poses a limit. In general, it’s close to F/2.8 in terms of the depth-of-field that you see here, so if you use a wider aperture with a more limited depth-of-field, there’s simply no way of seeing wether it’s in focus, no matter how good your eyes are. You can get a special matte screens for some camera’s, but they tend to darken the image in the viewfinder.
  • Your AF sensor can only check for focus to a limited degree. This is also a technical limitation not by the AF sensor itself but by the aperture that forms between the mirror and the the AF sensor. You can use a wider aperture for lens, but the AF sensor won’t see this larger aperture and can therefore only focus to what it can see. Usually the center AF point in most camera’s is more sensitive than the others, because it lies at the center of the aperture and has less light fall-off, but even in professional camera’s it doesn’t do much better than F/2.8, so even if your AF system confirms your focus, it’s only confirmed to what it can focus to.

Without live-view-with-magnification, your best best is to take a shot, check it, take one again, check it, or live with the limitations of your system that even though you might need the light (for low-light photography) the focus may not be as accurate.

How to focus with wide aperture lenses

I propose some tricks that can be used with lenses that have mechanical coupling with the focus ring (Anything in this answer does not apply to focus by wire lenses like Zuiko Digital lenses that require power from camera body to focus):

Rock the Focus

  • Step 1: I Just try to focus quickly as best as possible, then, re locate fingers on the focusing ring trying to adopt a “neutral feeling”
  • Step 2: Intentionally move the ring out of focus until I clearly see that I am out of focus, noting how much I’ve moved my fingers but without loosing my point of contact with the ring (this is very important, do not release the focus ring).
  • Step 3: repeat step 2 but in the other direction, always without releasing the ring at any moment. Note how much you move your fingers. Also try to achieve the same amount of “out of focus” that you observed in step 2.
  • Step 4: The true focused point will be aproximately the “average” of the two out of focus points you calculated in steps 2 and 3. Move the focus ring back and forth a shorter distance every time, trying to math the “defocus amount” at each extreme until you find the average (think of a marble ball in a concave surface, rolling free until finding rest right in the middle or lower point).

All this should be done without releasing the focusing ring at any moment, the keystone of the “method” is that you have to be aware of the amount of displacement of the focusing ring at all times, and learn to feel it with your fingers. (This assumes you are holding the camera by resting its weight on the palm of the hand, so you are not moving the hand relative to the camera, only the fingers). You don’t need to iterate too many times, four to six movements should be enough.

Zoom Scales

Another alternative is to use focusing scales. This is a feature that almost all old (manual) lenses had. It was markings on the lens barrel that allowed to know what distance the lens was focusing. You can create a focusing scale for your lens in an easy DIY way:

First note if the focus ring moves against a fixed part of the lens barrel. Place a small sticker and draw a line on it it along the lens axis. Now measure how much the mark “travels” around the barrel. Now adhere to the barrel a stiker that covers the full travel of the mark (Im thinking of those long and narrow labeling stickers to apply in CD case spines, but any nice, suitable autoadhesive paper cut to fit will do). Now affix the camera to a tripod, aim it horizontally (not tilted up nor down) and select an object you can place in front of camera at various distances. A chair, another tripod, a tall lamp, etc. Now place the object at various measured distances: 1, 2, 3, 5, 10 meters or 3, 6, 9, 15, 18 feet. For every distance Use autofocus so the lens focuses on its central focusing point, and mark the barrel sticker at the point that it coincides with the marking on focusing ring, label the focusing distance. Now you have a lens with focusing scale.

Next time you have to focus on a difficult situation, like a low contrast scene/object, low light, though glass, etc. given that you can measure or estimate the distance, you can pre select it using your lens’ scale. If you practice, you’ll get good a guessing distances.

This method (of creating your own focusing scale) works best on fixed focal length lenses, but some zoom lenses are suitable for the operation, however, some zoom lenses focus at a different ring position at different focal length at the same distance, making the scaling a lot more complicated (but not impossible).

Focus Bracketing(sort of)

This works best with static scenes and with camera on a tripod.

  • Step 1: Compose and quickly focus as best as possible, then move the focus ring in one direction until slightly out of focus.
  • Step 2: Take a shot, and move the ring a little in the oposite direction you did in step 1.
  • Step 3: Repeat until you notice you have it out of focus again.
  • Step 4: Review (posibly later, on a computer) your shots at 100% zoom to select the correctly focused one.

An alternative to this, while shooting static subjetcs but without a tripod is: As usual, quickly focus, as best as posible, lean back, shot, “un-lean” a little, shot, repeat until you are in fact leaned forward. All of these without changing focal length nor moving the focus ring. Review and select the one with the correct focus. (This last one is the only one that may work on focus by wire lenses, assuming you can turn off autofocus)

Posted April 20th, 2021 by Shelly Perry & filed under Travel Photography.

One of the most powerful photography techniques to learn is selective focus. It makes your photos look more intentional, more professional, and lends impact, directing the viewer’s eye.

What is Selective Focus?

Selective focus is basically what it sounds like. You select what portion of your image you want to be in focus, while blurring out the background and/or foreground.

Often, you’ll hear the term “depth of field” in photography, referring to how much or little of the photo is in focus, from the object closest to the viewer, to the horizon. When everything in a landscape photo is in focus – from the blades of grass in front, to the horizon miles away – that’s considered a “deep” depth of field.

In this case, we’re mostly talking about close-up photos, in which one small section of the photo is in focus. That’s called a “shallow” depth of field.

This technique can be used in a variety of ways and helps to bring a sense of depth and interest to your photos. It’s very useful with close-up photos and, when done right, can give your shots a more professional feel.

Selective Focus Examples:

In the shot below, notice that the area toward the bottom third is in focus, while all the texture toward the top loses detail.

How to focus with wide aperture lenses

Shot at: ISO 100 70mm F/3.5 1/100 sec.

To create selective focus, the camera settings you need to pay attention to are:

• The aperture size (or the opening of the lens which is measured in f-stops)
• The focal length of the lens (70mm is the maximum zoom on my lens, but yours may vary)

Now take a look at this next dessert shot (food photography, by the way, is a classic subject for selective focus):

How to focus with wide aperture lenses
Shot at: ISO 100 55mm F4.0 1/160 sec.

Notice the zoom on the lens is not quite as far out (55mm compared to the last shot at 70mm) and the aperture is F/4, instead of F/3.5). The results are similar (notice how the leaf is slightly out of focus) but not quite as dramatic.

Here are three ways to create selective focus in your photos:

1. Try setting your camera to smaller f-stop numbers. Smaller f-stop numbers actually increase the size of the aperture, or opening, in the lens. As in the above examples, use something between F/4 and F/2.8. You can get more dramatic blur if you open up the lens (using a smaller f-stop number).

If you’re a point-and-shooter, you may not be able to adjust your aperture by dialing in a different f-stop number, but you can try using the “macro” setting on your camera, if it has one. (Check your camera manual for instructions.) And if you don’t have a macro setting, try putting it in “portrait” mode. Again, check your camera manual.

2. Zoom in. The longer the zoom, the more dramatic the blurred area will be.

3. Shoot from a low angle. Notice, in the examples above, the perspective of the subject relative to the camera placement. In the dessert shot, for example, notice how the side of the leaf and the plate edge closest to the camera are out of focus, as are the cookie and the back side of the plate. This is because they are varying distances from the lens, exaggerated by shooting across the plate, rather than straight down at it. Now take a look at this last photo of a wood carver in Ecuador:

How to focus with wide aperture lenses
Shot at: ISO 100 70mm f2.8 1/60 sec.

Here, the zoom was maxed out as far as it would go (70mm) and the aperture, or f-stop, was at its widest (F/2.8). This example lets you see that selective focus can be used in a variety of ways, and combined with Rule of Thirds, it becomes a very effective tool in composition.

The point of focus in this example is the man’s hands as he works his carving. The blurred-out foreground containing the tools of his trade gives us a bigger picture without being too distracting. Had this shot been in focus corner-to-corner, it would have had much less impact, as our eyes would tend to wander to all the various objects.

Equipment Needed for Selective Focus

With selective focus, it’s all in the lens. It’s much easier to get a shallow depth of field, such as in the shots above, when you’re not shooting with a wide-angle lens. Anything from 50mm and longer will give you the opportunity to blur the background or foreground. The longer your lens, the easier it gets.

For example, with a 200mm lens, you can stand 20 feet away from your main subject, and still blur out the background.

As I mentioned above, the other factor is the aperture, or f-stops, on your lens. Some lenses will let you “open up” to a very wide aperture, such as 2.8, 2, or 1.4. The smaller the number, the more you’ll be able to blur out. Check your lenses to see how small you can go.

When to Use Selective Focus

Above, I mentioned that landscape photos often have a “deep” depth of field. For landscape shots, selective focus is usually not the best choice. Typically, you want to have everything in focus, from the foreground to the mountains in the distance.

Selective focus is a powerful tool for directing the viewer’s eye to something. It works wonders to show just one person in a crowd of people… a detail on the side of a building… or a single flower in a field.

It’s also great for getting rid of distracting elements in the background by blurring them out.

You can check out our Travel Photography page to find all you need to know about travel photography and how you can make a living from travel photography right now.

How to focus with wide aperture lenses

Daven Mathies/Digital Trends

Ever see a photograph with a dreamy, out-of-focus background? Or perhaps a landscape with pin-sharp details from the closest foreground elements all the way to distant clouds? Aperture is what allows photographers to take control over how sharp or how blurred their photos are, and is one of three elements that determine a photograph’s exposure. But what is aperture, really?

As part of the exposure triangle, aperture is an essential camera setting, helping determine how bright or dark the image is. Unlike shutter speed and ISO — the other two sides of that triangle — aperture isn’t in the camera, but the lens. The word aperture simply means an opening, and that’s exactly what the aperture of a lens is. By changing the aperture setting, you increase or decrease the size of that opening, letting in less or more light, respectively.

Here’s everything new photographers need to know about using aperture.

What is aperture? The basics

Imagine you are filling a jar with sand. Both jars have the same capacity, but one has a wide opening like a Mason jar and the other has a narrow opening like a soda bottle. If you drop a handful of sand above each jar, which jar is going to collect more sand?

Think of aperture in similar terms. An iris composed of overlapping metal blades inside the lens opens and closes to make the aperture larger or smaller. A larger opening is going to let in more light, making a photo brighter. A smaller opening will let in less light and make the photo darker.

Apertures are measured in f-numbers, or f-stops, which is where the concept can start to get a bit more confusing. A small f-number, like f/2.8, is a wide aperture. A larger f-number, like f/16, is a narrow aperture. Just remember that f-numbers are opposite of what you’d expect: a low number means wide, and a higher means narrow. (F-numbers are actually the denominator of a fraction, so the math isn’t as backwards as it seems.)

Of course, there are more aperture settings than just f/2.8 and f/16. Some lenses may open as wide as f/1.4, or stop down to f/22 and beyond. As with shutter speed and ISO, aperture controls exposure in the unit of “stops.” Increase the size of the aperture by 1 stop, and you’ve doubled the amount of light coming through the lens. Decrease it by a stop, and you’ve cut the amount of light in half. Modern cameras allow you to make adjustments in 1/3-stop increments (oh no, more fractions!) so that you have fine control over the exposure.

Here are some common f-numbers arranged in full-stop increments: f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16. This shows that f/2.8 is half as bright as f/2, which itself is half as bright as f/1.4. That means f/2.8 is four times darker than f/1.4, although all you really need to know is the number of stops: If you open the aperture by 2 stops, you’ll need to change the shutter speed or ISO by two stops to compensate.

How do you change the aperture on your camera?

While you need to also understand ISO and shutter speed in order to control exposure in manual mode, you can dip your toes in slowly by starting with aperture priority mode. This mode, designated on most camera mode dials as A or Av, allows you to control just the aperture, while the shutter speed and ISO can remain on auto. (It is possible to take the ISO off auto if you want). Aperture priority mode is an easy way to learn how aperture affects images — once you understand aperture priority (and its counterpart, shutter speed priority), manual mode won’t seem so daunting.

How to focus with wide aperture lenses Hillary Grigonis/Digital Trends

On some cameras or lenses, the aperture is adjusted via a dedicated ring around the lens, but most modern cameras put aperture control on the camera body itself, usually in the form of a command dial. As you turn that dial, you should be able to see the f-numbers changing in the viewfinder or on the LCD screen. The range of available numbers will vary based on the lens model, so if you reach a point where the camera won’t change the aperture any more, you’ve reached the beginning or end of that range.

Aperture priority mode is a semi-automatic — your camera is still choosing the best exposure for the image by controlling shutter speed (and, optionally, ISO). That means in aperture priority mode, you probably won’t see your image getting brighter or darker as you change the f-number.

But wait, why use aperture priority mode at all if the camera is still making the exposure decisions for you? Aperture controls more than just the exposure of the image — it also adjusts depth of field.

Aperture and depth of field

Depth of field is a photography term that simply refers to how much of the image is in focus, from foreground to background. You’ve probably seen portraits with very blurred backgrounds and you’ve probably seen landscapes where most of the image is sharp. The difference between the two is aperture.

The worst thing you could possibly do in the photo world would be considered heresy and sacrilege in the church of photography. Truthfully, if you buy a lens with a fast aperture, you should never stop it down. You bought it to get that beautiful bokeh look. It’s also probably the reason why you upgraded from your phone. These lenses are wonderful: it’s why you’re paying so much for them. So we’re going to let you know why you should never stop your lens aperture down.

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You Can Focus Stack Instead

How to focus with wide aperture lenses

Modern cameras, at least the good ones, have the awesome focus stacking feature. This means you can shoot an entire scene wide open. Then the camera will take tons of photos, blend them all together, and make a single photo. This is popular in the macro photography world. And for a long time, you could only do it through post-production. Want to know what to do?

  • Set your camera to shoot wide open.
  • Focus on the closest spot you want in focus.
  • Then set the camera to photograph as much of the rest of the scene you want.

If you want someone’s entire face in focus, this is the best way to do it. You won’t need to stop the lens down either.

Interested in more? Here’s a piece we did on Focus Stacking and a pertinent quote:

“Bargh starts off the video explaining the pitfalls of using the smallest aperture when lenses designed to shoot best at f8. Using a miniscule aperture also means you’ll need a tripod to keep the camera steady for long shutter speeds or invest in a ring light, which can introduce unwanted light streaks. As Bargh highlights going with a wider aperture also allows bokeh to invade most of the frame.

This is where focus stacking comes to save the day. All shooters have to do is keep the camera steady with a tripod or in hand whilst they take multiple images of the subject at different focusing distances. Once users have the images they can migrate the images over to piece of software. There are a few programs that will stitch together images including Zerene Stacker and Photoshop, but Bargh suggests Helicon Focus as the best paid solution.”

The Best Images Just Have Lots of Beautiful Bokeh and a Wide Aperture

Years ago, we looked at lots of beautiful images shot of the world. Many of them had most of the scene either in focus or out of focus. But none of these images were shot because of the bokeh. Today’s photos are different. Look at various portraits on Instagram, Facebook groups, and Zoom events.

How to focus with wide aperture lenses

Modern Lenses Were Designed to Be Shot Wide Open

Finally, in the past couple of years, companies have made their lenses able to be shot with wide-open apertures most of the time. They know the market wanted it: that’s why they gave them more aperture blades, most micro-contrast, deeper saturation, etc. Manufacturers also like to tout how their lenses perform when shot wide open in MTF charts. Of course, this isn’t the case for everyone. Modern lenses are also very clinical: there’s no vignetting or anything. Some of us like character in our lenses.

That’s yet another reason to not stop your lens down. You’re going to kill any and all character. If you want it, you can just add it in via post-production.

How to focus with wide aperture lenses

Focal length, usually represented in millimeters (mm), is the basic description of a photographic lens. It is not a measurement of the actual length of a lens, but a calculation of an optical distance from the point where light rays converge to form a sharp image of an object to the digital sensor or 35mm film at the focal plane in the camera. The focal length of a lens is determined when the lens is focused at infinity.

Lens focal length tells us the angle of view—how much of the scene will be captured—and the magnification—how large individual elements will be. The longer the focal length, the narrower the angle of view and the higher the magnification. The shorter the focal length, the wider the angle of view and the lower the magnification.

How to focus with wide aperture lenses

How to focus with wide aperture lenses

Zoom vs. Prime Lens

There are two types of lenses-prime and zoom. Prime lenses have a fixed focal length and zoom lenses have variable focal lengths.

Zoom Lens Benefits

Prime Lens Benefits

The main advantages of prime lenses or fixed focal length lenses are their size and weight as well as their maximum aperture or f/stop. Prime lenses tend to be more compact and lightweight than zoom lenses.

Prime lenses also tend to have a larger maximum aperture (f/1.4 to f/2.8). This is an advantage when shooting in low light conditions as it will increase the possibility of hand holding the camera and freezing the subject without shake or blur caused by the longer exposures. Photographing using prime lenses with large apertures also means you can get a shallow depth of field which is useful for portraiture where you might want a softer or blurred background (also known as bokeh).

Lens Focal Length Comparison

Wide-angle Lens

FX format approx. 14 – 35mm / DX format approx. 10 – 24mm

Wide angle lenses are popular lenses for landscape photography, interiors, large group photos and when working in confined situations.

How to focus with wide aperture lenses

© Diane Berkenfeld & Lindsay Silverman

Standard Lens

FX format approx. 50 – 60mm / DX format approx. 35mm

Standard lenses are popular as they are closest to the angle of view we humans see. These lenses have minimal distortion, which can be flattering to the subject. They tend to use large apertures and allow a lot of light to enter the lens which makes them fast in low light conditions. Large apertures (f/1.8 – f/1.4) also produce a pleasing out-of-focus effect to the background which concentrates the attention of the viewer on the subject. Standard lenses are the popular choice for a wide range of photography including portraiture, nature and low light situations where the photographer can not use a flash or is looking to capture the scene with available light.

How to focus with wide aperture lenses

Telephoto Lens

FX format approx. 70 – 200mm / DX format approx. 55 – 200mm

Telephoto lenses between 70 – 200mm are very popular lenses for portraiture and product photography as well as nature and wildlife imagery. They allow the photographer to produce close crops on the subject. In the case of portraiture a telephoto allows the photographer to take the photo at a distance that does not intrude upon the subject.

One of the many things that often differentiates a photographer from a snap shooter is the use of depth of field. Shallow depth of field is one of the best compositional tools we have, by using out of focus regions in an image we can concentrate the viewers eye on the main subject. Whilst you can get limited depth of field with some kit lenses, to really perfect the art, you need a lens with a wide aperture, f2.8 being an ideal starting point. Of course wide aperture zoom lenses do not come cheap but a better option may be to purchase a prime lens with a wide aperture, for example an 85mm f1.8 would be an excellent addition to anyones kit bag. Prime lens have the advantage of generally being cheaper and having wider apertures.

Note: We have some notes on achieving pleasing shallow depth of field effects with a kit lens here.

When it comes to shooting with a shallow depth of field, there are several things that you need to remember. Firstly the closer you are to the subject, the more shallow the depth of field for a given aperture. Secondly a longer focal length will give a shallower depth of field for a given aperture and subject to camera distance.

So armed with this knowledge, what sort of things can we use depth of field for?

One of the most common uses of shallow depth of field is in portraiture. Usually in a portrait shot, you are trying to bring the viewer’s attention to the eyes. By using a wide aperture you can throw the background completely out of focus, depending on how wide you are and your lens and position, you can also try to throw the subject’s nose out of focus. This is useful if you really want to draw the viewer in to the subject’s eyes but it can be hit or miss depending on the subject.

The aforementioned 85mm is often regarded as the best portrait lens because you can get in close to your subject using a wide aperture and the slight compression that an 85mm provides can be very flattering to your subject.

Of course portraiture is not the only area of photography where a shallow depth of field can be a creative tool. Landscape photographers can isolate elements of a scene such as flowers or an individual tree. By getting down low, they can use an out of focus foreground such as long grass to draw the viewer’s eye out to a more distant subject.

In studio shots, again a shallow depth of field is used to draw attention to a particular element with the product, using out of focus areas as leading lines to the main part of the subject.

An out of focus foreground draws the eye to the subject by Jason Row Photography, on Flickr

Macro photography is an area where it’s quite easy to obtain and use a shallow depth of field, because of your proximity to the subject. Here, though, because you are so close, you might find the depth of field too shallow and may have to stop down your aperture a little to make sure the right parts of the subject remain in focus.

How to focus with wide aperture lenses
Wide aperture and macro by madmarv00, on Flickr

Don’t Forget About Good Composition

When using shallow depth of field in any aspect of photography, composition is important. Out of focus areas can be used as leading lines whilst positioning your in focus subject on one or more of the thirds can dramatically improve the composition.

One of the things that goes hand in hand with a shallow depth of field is the mysteriously named bokeh. Bokeh is a subjective word that defines the quality of the out of focus parts of an image, in particular the reflections and specular highlights. The quality of bokeh is defined purely by the lens and is one of the major considerations when purchasing a lens specifically for shallow depth of field photography. Lens reviews will often describe bokeh as being good or bad but the only way you can really know if you like the bokeh from a specific lens is to either look at image samples or to try the lens yourself, it’s a highly subjective thing.

How to focus with wide aperture lenses
Bokeh is subjective but important by madmack66, on Flickr

Shallow depth of field is one of the most powerful compositional tools that we have as photographers. Even using a kit lens we can get a decent shallow depth of field if we position our selves well but to get the best looks, it’s worth considering buying a good wide aperture lens either prime or zoom, new or used. Once you start shooting shallow, you might find it quite addictive.