Uses for a small aperture :: Digital Photo Secrets
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Uses for a small aperture

by David Peterson 3 comments

If you’re a beginning photographer, the concept of aperture can be a little confounding. Smaller numbers equal larger apertures? Smaller apertures equal larger numbers? That’s all pretty confusing.

Fortunately, modern cameras are designed to be easy for beginning photographers to use, which means that you may not have figured there was much point in learning about and understanding aperture, at least not right away. And because many modern cameras also have scene modes—which can help you make good choices about your camera’s settings without necessarily needing to understand what is happening behind the scenes—you have even less incentive to think about aperture.

But auto settings and scene modes can only take you so far, and at a certain point you're going to want to have more creative freedom and control over your photos than what those automatic settings can give you. And one of the first things that you need to understand is what aperture can do for you creatively.

Uses for a narrow aperture

In this article we're going to focus specifically on the uses for a narrow aperture. When you select a narrow aperture, you are choosing to make the hole between your lens and your image sensor smaller. That smaller hole lets in less light, which limits your ability to shoot in low light conditions. But it does also do something positive for you—that narrower aperture gives your image a broader depth of field.

Depth of field explained

Depth of field is the term used to describe the amount of a scene that remains in focus from foreground background. An image with very broad depth of field is completely sharp, from the foreground elements to the very distant background elements, while an image that has shallow depth of field may not have many sharp elements at all, beyond the subject or focus point itself. The reasons why you might choose a shallow depth of field over a broad one are creative. Shallow depth of field helps separate your subject from its background, while a broad depth of field maintains detail throughout a photograph.

Landscapes

The most common reason why you might select a narrow aperture is because you’re photographing a landscape. When you shoot a landscape, you typically want the entire scene to be in focus. If the entire scene is not in focus, it's not really landscape—it's an isolated object within a landscape. So when a photographer takes a photograph of a landscape, she will typically select a very narrow aperture of around f/22. If there is something in the very near foreground that needs to be kept in focus, it is even more important to keep that aperture narrow because you want that near object to be just as sharp as the distant ones.


Landscape by Flickr user *ღ* M.Al-Baker *ღ*

Selecting a narrow aperture typically means selecting a slower shutter speed, so you may find that you can't hand-hold your camera when you use a very narrow aperture, because your shutter speed will be too slow. Taking a photograph hand-held with a slow shutter speed can result in camera shake, which can give your photograph a jagged, blurry appearance. Except on a very bright day (and there’s a good argument for not shooting landscape photos on very bright days) it is a good idea to always bring a tripod along with you whenever you're planning to shoot scenery.

Along with the tripod you will also need a remote release, which will allow you to make an exposure without actually touching your camera. During a long exposure, just pressing that shutter button can be enough to cause camera shake, so make sure you either have a remote release or that you use your camera’s self timer feature to count down around five seconds between the time you touch the button and the time the shutter opens.

Macro photography

Similarly, you'll want to select a narrow aperture when shooting macro photos. A macro photo is any image taken at very close range of a very small object. When you get close to a tiny object such as insect or a small flower, you’ll notice that you get much shallower depth of field even at apertures that would normally give you good clarity from foreground to background. That's because the closer you get your subject, the less depth of field you're going to have overall—and at those very close ranges your depth of field can actually be measured in millimeters. So you need to use those narrow apertures in order to bring the more distant details into focus.

  • Canon EOS-1D Mark III
  • 200
  • f/22.0
  • 0.003 sec (1/300)
  • 50 mm

Pinwheel by Flickr user John-Pa

Just like with landscapes, you may find that you need a tripod when shooting macros. This isn't just because of the slower shutter speeds you'll have to use (although that does factor into it), it is also because the closer you get to your subject the more any camera shake will be magnified. That means that you can shoot at reasonably faster shutter speeds and still get some noticeable blur caused by the movement of your camera. And the movement of your camera may also throw your focus point off, so you'll get sharpness in parts of the frame that you hadn’t intended, while those you did intend to be sharp will end up blurry.

Starbursts

Have you ever admired a photograph like this one:


San Francisco - Pier 7 by Flickr user nagarajan_kanna

This photographer did not use any fancy post-processing techniques or filters to achieve this effect. This effect can actually be produced simply by selecting a narrow aperture.

The starburst effect is actually a function of those aperture blades, or the overlapping pieces of material that help adjust the size of the aperture opening. When light passes through the smaller aperture opening, it bends around the edges of those blades, which is what creates the starburst rays.

In order to achieve this effect, you need hard points of light such as a string of Christmas lights or a row of bright streetlights. And because you’ll be shooting at narrow apertures in the dark, you will need longer shutter speeds—which, of course, means that you will absolutely have to have a tripod.

Remember that when you shoot after dark you can't really trust your meter, so it’s a good idea to take a few bracketed exposures. To bracket your shots, shoot one that is at your camera’s recommended meter reading, and then check your screen to see if you like the results. If not, take a few shots that are reading as underexposed, and a few shots that are reading overexposed, depending on how much darker or brighter you want the scene to be. Remember to adjust your shutter speed, not your aperture. To achieve the starburst effect, your aperture needs to remain narrow—for the most dramatic effect, choose f/22.

You can also get starbursts during the day if you use a narrow aperture and include the sun in the frame. Again, metering a scene like this one will be a challenge—because the sun is such a bright light source, your meter may want to underexpose the scene to compensate for all of that light. Bracketing your shots is going to give you the best chance at good results.

Car light trails

Light trails are a fun and creative way to capture some interesting photos, and they also require narrow apertures. The reason why you need narrow apertures to shoot light trails is because these scenes are often shot with very long exposures—and long exposures require narrow apertures. Those very long exposures, in turn, are necessary to get a complete trail from the left of the frame to the right (although the speed of the traffic does have some influence).

  • Canon EOS 7D
  • 100
  • f/9.0
  • 20
  • 24 mm

Downtown by Flickr user Will Hastings

A tripod, of course, is an essential part of the gear you’ll need to shoot light trails, but you’ll also need a camera that can do “bulb” mode and a willingness to experiment. Select a narrow aperture and use a remote release to open the shutter just before a car enters the frame, and then close it again just after it leaves. Check your screen and make adjustments to your ISO and aperture as needed—again, for night scenes like this you can’t completely trust your meter.

Misty waterfalls

There are other creative reasons for using a narrow aperture, and one of them is because you may find yourself wanting to use a slow shutter speed even though the sun is out. A good example of this might be when you're shooting a waterfall. You know those beautiful, soft, misty-looking images of waterfalls, which seem more like fog than actual water? Those are all shot with a slow shutter speed, and you can't achieve a slow shutter speed during the day unless you're using a small aperture, or you happen to be in a very dark place.

I will say that sometimes the smallest available aperture on your camera isn't necessarily going to be enough to allow for a slow enough shutter speed for that soft water effect. Sometimes you need a neutral density filter to help cut back on the amount of light in the scene. This is mostly going to be a problem when you're shooting in a bright place, or at a bright time of day such as the late morning or early afternoon. If, however, you are shooting during the golden hour—that hour just after sunrise or just before sunset—there's going to be less light overall and you will probably get some pretty good images just by selecting a small aperture and long shutter speed combination. Remember (again) that you do need to use a tripod any time you are shooting with a slow shutter speed.

Conclusion

If the concept of aperture is still new to you, and you're still a little shaky on it overall, I recommend you put your camera in aperture priority mode and spend a day—and possibly part of your night as well—shooting photographs with a narrow aperture setting (remember: narrow aperture corresponds to larger f-numbers). I think you'll find it that you are so pleased with some of the creative effects you’re able to achieve that you will wonder why you didn't step outside of auto mode sooner.

Summary:

  1. What is aperture?
  2. Depth of field explained
  3. Landscapes
  4. Macro
  5. Starbursts
  6. Car light trails
  7. Moving water

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Comments

  1. JUDY K says:

    You just explained the true essence of photography...basic concepts that once understood, will improve one's photography exponentially!!!

  2. Jan Smith says:

    This helping to understand aperture and depth of field. Now to practise.
    Your tutorials are always helpful.

  3. J.Worrick says:

    Great Info, however I tried to use the bulb function while in aperture mode and could not get there. I had to use
    manual mode to use bulb. Av=F22 Sv=6" iso was at 200. Any comments on the settings.
    I was just trying it out in my office. I have the cannon T4i.

    Thanks,
    J.Worrick

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