Hi my wonderful readers, hope you are doing fine. In the today’s article I will explain what is aperture in photography.
Aperture is like the pupils of our eyes, it either expands or shrinks as you move from a brighter environment to a darker, to adjust to the light.
Or think of window blinds, as you raise it up, more light is entering in the room, and when you lower it, the room becomes dimly lit, meaning that less light is entering the room. Same with aperture.
Only that, aperture captures light that is transferred into the cameras sensor to expose the image from the frame.
What is aperture in photography?
Aperture is one of the crucial settings besides shutter speed and ISO in the exposure triangle. It is the opening in the lens which lets a certain amount of light into the cameras sensor. Depending on how you set it.
Aperture is measured in f-stop numbers. And you can recognize it as f/1.4, f/2, f/5.6 and so on, some cameras will show it without slashes, like, f8, f11, f22, etc.
The lower the f-stop number, the wider the aperture is, meaning that more light is entering into the sensor. And the higher the f-stop number, the narrower the aperture is, meaning that less light is entering into the sensor. See image below.
At first, it’s a little bit confusing, but as you work more often with them, you will get used to them. Just keep in mind that a low number means wide aperture and high numbers means narrow. It’s a reverse logic.
Aperture is the camera setting which lets you control depth of field. You can make it shallow (more blur in the background) or deep (more sharpness in the image).
You can set aperture by turning the dial to Av/A (for aperture priority mode) or M (for manual mode).
How aperture affects depth of field
As I said above, you can control depth with aperture. A deep depth of field shows the entire image sharp and a shallow depth of field shows only the prime subject sharp and the rest of the background becomes blurry.
Wide aperture settings (low f-stop numbers), will make your images come out with shallow depth of field. And narrow aperture settings (high f-stop numbers), results in deep depth of field.
The deep depth of field is often seen in landscape photography, where the photographer tries to capture the entire scene in focus. This requires an aperture setting of f/16 or f/22. Here is an example.
This is an image I took from a citadel to capture all the view in the horizon. As you can see, the image is completely in focus, both foreground and background are sharp.
Shallow depth of field is seen in portrait and macro photography. In these types of category, the photographer wants only the subject to be in focus and the rest of the background blurred out. Lets see some examples.
As you can see in the images above, everything is blurred out in the background and only the rose and the lion are in focus and sharp.
Now that we have clarified aperture and depth of field, lets move further on what is aperture in photography and see what impact has on the brightness of your images.
How aperture affects brightness
Just like our pupils adjust to different environments (bright or dark), so is aperture, captures light into the sensor by increasing and decreasing its blades.
A wide aperture (low f-stop number) can capture a generous amount of light, while a narrow aperture (high f-number) let less or squeeze a small amount of light into the cameras sensor.
This will lead to an underexposed (darker photo) or overexposed (too bright) image, if you do not set it properly. But, luckily there are the other two settings, shutter speed and ISO, with which you can compensate the amount of light.
As you can see the image above, at a wide aperture (f/2.8) the image is overexposed. Means that too much light entered into the sensor.
If we look on the next image at f/5.6 the exposure is normal, means that the image is properly exposed.
But, if we look at the images at f/16 and f/22, we can see that the images are too dark, underexposed. This means that the lens didn’t let enough light into the sensor. This is how aperture affects exposure if it’s not set properly. Now lets move on to the next section.
Aperture in macro photography
In macro photography to make your subjects stand out you probably want to shoot at a lower f-stop number to blur everything in the background.
But, if you shoot at the widest aperture (lowest number) which should be f/1.4, your subject will end up out of focus on most parts. Or it will be in focus only the part that is closer to the lens. Now you think, oh ok, then I should raise it to a higher number.
Yes you should and is recommended to make your subjects sharp. But don’t raise it too much, if you set it, lets say, to f/16 or f/22, this could lead to a problem which you will see it if you zoom into the image.
And this problem is caused by lens diffraction. As you increase the f-stop number, your images will become less and less sharp, and this is noticeable in macro photography. You can find a deeper explanation of diffraction in the link below.
<<<< What is lens diffraction >>>>
Anything that goes beyond f/22 will make your images appear less sharp, because the lens squeeze only a tiny fraction of light into the sensor.
So, the ideal f-stop number for macro photography is between f/5.6 and f/8 maybe f/11 in some cases when is enough light around your subject. Look at these two examples below.
If you look closer, you can see in the angels eyes how sharp is the image at f/5.6 and how blurry is the image at f/22. This is the effect of lens diffraction. So, you should stick with f/5.6, f/8 and occasionally f/11, if you want sharp and detailed images.
And also you can practice focus stacking for more sharpness and details. Flash light also helps in sharpness.
Now that you learned what aperture is and what effect has upon your images, go and play with the settings to get familiar with them.
Don’t forget that not only aperture has impact on your images, ISO and shutter speed plays their roles in creating properly exposed and quality images.
Have any questions or concerns regarding aperture, please don’t hesitate to comment them below and I will be more than happy to help you out. Be safe and take care.
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