Lens Aperture Explained – For Beginners

Welcome to my post ” Lens Aperture explained for Beginners “. In this post I will try to explain the lens aperture in more technical yet simpler details.

What is Lens Aperture?

Lens aperture basically, in the simplest terms, is a hole in which light can pass through. That hole can vary in size. The size or diameter of the lens aperture, or the hole determines the amount of light that will pass through. Obviously, the larger the hole, more light will pass through, and smaller the hole, less light will pass through. Therefore, a photographer can control the brightness( and a few other things– explained later) of the photo by selecting the size of the aperture.

How is Lens Aperture Selected

On photographic lenses, the aperture is marked as a sequence of numbers. These numbers look like (1.4 , 1.8, 2, 2.8, 4, 5.6 . and so on). These numbers refer to the diameter of the hole. Smaller number means wide opening, and larger numbers mean narrow opening. That simple. Photographer refer to these numbers stops or f/stops. So if I select an aperture of 2.8, I would say I’m at f/2.8. On modern lenses, aperture is selected electronically on the camera body- yehhh modern technology! Camera in auto mode can automatically select the right aperture based on the lighting conditions of your scene. This process of selecting aperture is also automatic in your point and shoot cameras, smart phones, tablets or any other mobile device that has a camera built into it.

aperture ringlens aperture

So what do these apertures numbers mean?

These numbers as mentioned earlier control the diameter of the aperture. Aperture value of 1.8 will result in a wide opening compared with an aperture value of 5.6 will result in a narrow opening. Aperture values such as are fraction of 1. Therefore if your do the simple math, 1 divided 1.8 (f/1.8) will yield approximately 0.55. And 1 divided by 5.6(f/5.6) will yield 0.18. You see 0.55 is larger than 0.18. Figure below illustrates the f/stops


Depth of Field.

Lens Aperture not only controls the amount of light that passes through the lens. It also controls what is known as depth of field. Depth of field is the area around the focus point.

High f-numbers will produce sharp depth of field. More area behind and in front of the focus point will be in focus. Low f-numbers produce shallow depth of field. More area around the focus point will be out of focus. Photographer call this the ‘bokeh’ effect or creamy effect. Shallow dept of field with low f/stop makes the subject stand out and blurs the background.

sharp dofSharp depth of field (Nikon USA)

shallow dofShallow depth of field(Nikon USA)

How do I determine what aperture value to select?

Photography is careful mixture of three common camera setting. These setting are, aperture, sensor sensitivity(ISO), and shutter speed. Mastering these three essential components can result in stunning photography. There are some guidelines for selecting all three based on lighting conditions and whether your subject is moving or stationary. Photography is just as experimental as it is theory. So get your DSLR out and take some beautiful Autumn shots. More articles coming on other essential components of the camera.

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  1. Hi Pardeap,

    Thank you for the great article on aperture and how it not only effects the amount of light entering the lens but also the depth of field. I am a contributor to Shutterstock so spend a lot of time taking photographs. Now that I have read your article, I suppose I should make more effort in framing shots better than I have in the past.

    I look forward to reading your further articles.


  2. Hello Pardeap Sambi. Thank you for taking your time to explain what what Lens Aperture is. I have heard about it before but never truly knew what it is. So aperture of high value will have a wide Operating while aperture of low value will have a wider opening. I love your technical but simplicity. Keep educating us.

    1. Author

      lower value(1.8) means wider opening, higher value(5.6) means narrow opening

  3. Great guide through the essentials of lens aperture.

    Usually I’m a quick snap photographer, taking pictures of live events like parties or meetings.

    Recently I had to learn that some more skills would be useful when taking images for my website.

    I have a website about Thailand and there I need pics of food, events in the evening and at night.

    As for now I have no extra lens, just a compact Panasonic DMC-FX35. I noticed though there are similar adjustments I can make.

    I’ll mark this site now and do some training here, thanks 🙂

    1. Author

      Please let me know if you need help choosing a good dslr.  I’ll be posting more articles in the futrue. Thnx

  4. Dear Pardeap,

    Thanks for the informative and helpful post.

    From your post I got new insights on lens aperture. One of my friends is very much interested in Photography and I am going to share this post with him. I strongly believe he will enjoy reading your post.

    I started reading your post with zero knowledge on Photography but now I gained some knowledge for sure via your post. By reading your articles I believe I will gain more knowledge on Photography.

    Wishing you all the very best!


    1. Author

      I’m glad I could be help. I’ll be posting more informative and fun articles in the coming future.  Be sure to check back.  Thnx

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