Small aperture: what does it mean and when do you use it?

a chart of aperture values

When people say “small aperture”, there is often some confusion as to what it means. In this post, we’ll talk about small aperture, large apertures, and how they affect your photographs.

What is meant by small aperture?

A small aperture is a large f-stop number. The f-stop is a way of measuring what the aperture of the lens is at. The higher the f-stop, the lower the aperture – meaning less light will be let into the camera.

Small aperture vs big aperture

On the other hand, a small f-stop number means a large aperture. The smaller the f-stop number is, the larger the opening in the lens will be and more light will be let into the camera.

How to read f-stops

f-stops are indicated by the letter f and a number, like f/8 or f-8. Here’s the part that confuses most beginning photographers:

F stops go in the opposite direction of aperture!

To recap:

Higher f-stops means smaller aperture

Lower f-stops means bigger aperture

An f-stop of say f/16 will mean the opening in the lens is very small, allowing very little light through. An f-stop of f/2.8 on the other hand will mean the opening in the lens is quite large, and will allow a lot of light through.

You can use the f-stop to control the exposure in your photographs. Higher f-stops are good for photos in bright sunlight, and low f-stops are good for night photography or in situations where there is little light.

Common aperture and f-stop values

F-stops are standardized, which means that for the most part, the aperture on a particular f-stop on one lens will be the same as the same value f-stop on another lens.

When you are shopping for lenses, you’ll be able to see the maximum and minimum aperture the lens is capable of. This will help you decide on which lens to get.

For most everyday photography, a stock lens that can do f/2.8 up to f/16 will be fine.

For more specialized applications, you will need to get specific lenses that can manage apertures of up to f/1.4 or f/22 and f/32.

f/8 is about halfway(it doesn’t make sense, but that’s how it is) between extremely low and extremely high values.

a chart of aperture values

Combining aperture and shutter speed

Aperture needs to be used in conjunction with shutter speed, otherwise your photos will not come out correctly. At smaller apertures, where the lens is wide open, you need to use a faster shutter speed. Otherwise, you risk letting too much light into the photograph and over-exposing it.

At larger apertures, where the lens is stopped down(smaller), you will need to use a slower shutter speed. Otherwise, not enough light will enter the lens and your photos will come out darker.

In most digital cameras and dSLRs, you will find a function that will let you adjust the aperture and compensate the shutter speed automatically.

When you are starting out, this is a good setting to use. You can make a note of what shutter speed the camera used for your desired aperture, and if you’re not happy with the result, pop over to manual mode, set the aperture you need, and adjust the shutter speed based on what you noted in the first shot.

Aperture and depth of field

Aside from controlling exposure, aperture is also very useful for varying the depth of field of your photographs. Put simply, depth of field means how much of your photo is sharp and how much is blurred.

By adjusting the aperture, you can either blur the background and part of the foreground, or you can make the entire photograph relatively sharp.

This is especially evident in landscape photographs and portraits/macro photographs.

Related

Depth of field in portrait photographs

In a portrait or macro photo, you want to keep the subject as sharp as possible and blur out the background. Or for an artistic effect, you may wish to blur the subject slightly as well.

For these effects, you want to use a low or small aperture, which means more light will enter. Small apertures will blur the background and make the subject look more enhanced.

Remember that you will need to compensate for the greater exposure using a faster shutter speed.

This is an example of a photo with small aperture. The increased size of the lens allows more light in and blurs the background. If you notice, there is a little bit of blurryness on the edges of the subject, too.

Depth of field in landscape photographs

An example of using high aperture is a photograph of a landscape or a cityscape.

In these photos, you want the entire photograph to have even sharpness. A high aperture(less light coming in) will let you get this effect.

The degree of blurring in the background(less or more) is known as bokeh. Once you start incorporating bokeh into your camera work, you’ll notice a huge improvement in the quality of your photographs.

Remember that you will need to compensate for the lesser exposure using a slower shutter speed. In many cases, landscape photos are best taken from a tripod since your hands may not be able to keep the camera stable enough to avoid shakes.

This is an example of a photograph taken with a high aperture, or less light coming in. Notice how the sharpness is evenly distributed across the entire photograph.

How to set aperture in your camera

In a dSLR camera, you’ll typically find a dial with various letters on it. To control the aperture, you have two choices. Either set the dial to A or Av, which will let you control the aperture (typically by using the scroll wheel).

In Aperture priority mode, the camera will adjust shutter speed automatically to try and get you the best photographs.

If you want full control over your photographs, you can set the dial to M, which is manual mode. In this mode, you will need to adjust everything manually: shutter speed, aperture, and ISO.

Related

Difference between SLR and dSLR cameras

Rangefinder vs SLR cameras

Conclusion

I hope this cleared up the confusion about small and large apertures. Remember, in apertures, small numbers mean more light, and bigger numbers mean less light!