The Inherent Property of Photography

This post will actually be about technique, more specifically the aperture. Most photographers know that a combination of shutter speed and aperture together ensure a correct exposure whether it’s on a digital sensor or on film. But the aperture has a much more profound role to play in terms of visual language. It determines the depth of field of any photograph. It can make everything from close-up to infinity seem sharp or it can make the focus only a couple of inches wide and knock everything else out of focus. How can we use that creatively? Fundamentally in two ways. By reducing the depth of field we can make the viewer focus on the main subject or we can create an illusion of three-dimensional depth in the photograph.

The fact that a picture in itself is two-dimensional gives rise to special challenges in order to transform the perception of three-dimensional depth onto the flat surface. Depth is simply missing in any picture. It’s not a new challenge and it’s something painters through time have dealt with in various ways. Among other means they have used perspective to bring out a feeling of depth. The ancient Egyptions rendered a man at the far end of a row of marching soldiers as large as the man closest to the observer, and thus really didn’t create much feeling of depth. The old Chinese did the same on their rice paper paintings, but they were still able to create a feeling of depth. They always placed near object down in the left corner and faraway objects in the upper right corner of the frame. So even if a mountain in the foreground and a mountain in the background were rendered at the same size, the painting would still be perceived as being three-dimensional. Eventually painters, particularly in Europe, started to utilized convergence of parallel lines and diminution of object size to create a feeling of depth. And during the Renaissance they even went to extremes, by exaggerating the effects of convergence and diminution.

With the use of limited depth of field it’s possible to create another sensation of depth. The eye can only focus on one plane at a time. Objects in front of or behind this plane appear more blurred the farther away they are from it. As a result, contrasts between sharpness and blur, creates an impression of depth. This is something we can use creatively in our photographic language. A shallow depth of field will at the same time make the eye stay on whatever is focused and this it’s a great way to clean up an otherwise messy or chaotic background.

Most people know that the use of a wide angel lens results in more depth of field than the use of a telephoto lens. But it’s not quite true. What really matters is the scale of the object rendered. If you move in with a wide angel lens so that the object is rendered at the same scale on the image sensor as with a longer lens, the depth of field will be the same with the same aperture, albeit the perspective will be completely different. With this in mind it should also make sense that a camera with a small sensor, give rise to more depth field compared to one with a larger picture frame. As a matter of fact most point-and-shoot cameras have so small sensors that it’s virtually impossible to effectively limit the depth of field. That is why so many photographers chose a so-called full-framed camera, simply to have more options to play with (among other qualities). So to summarize: The only two factors that affect the depth of field are scale and size of the aperture. Use it wisely in your visual expression!

60 thoughts on “The Inherent Property of Photography

  1. I adore this shot, thanks for the technical information that you used to capture this. I have many lizards at my windows (and all over the patio) and love to catch them doing what they do, stalking or sunning…Thanks so much Otto.

  2. Well if this dude showed up on my window I’m not sure my hands would be steady enough for shutter, aperture, or anything else, until I got done with the screaming! Great photo and lessons, Otto 🙂

  3. Thank you for bringing this up in a very nice and easy to understand of the other part of aperture. We often thought it for getting more light or less light but along with that setting the DoF also changes (assuming the no changes to others part). In that respect, sometimes it is a trade off.

  4. what a bizarre situation with the frog! and i do miss my little Sony fullish frame, i know you have one… thanks for the talk…

  5. This really was helpful, Otto. I’m getting to the point where more and more of what you say makes sense. This past week, I was trying to photograph a very small, slender lily, close to the ground. The background was quite chaotic, and the only solution was to blur the background, in order to make the flower stand out. So: f/4.5.

    On the other hand, while trying to photograph a large field of flowers with trees in the background, I found 50mm with f/22 rendered the scene more sharply, and allowed me to capture far more detail, than I could with my telephoto lens. I lost a lot of good photos last year, trying to use the telephoto for things that needed a different approach. Live and learn, as they say. Of course, I’d revise that old saying to, “Live, practice, and learn. “

      1. I just learned another lesson, Otto. Always — but always — move photos from your camera’s card to your hard drive before messing with them. I just accidentally deleted 300 photos, including some of the most beautiful I’ve ever taken. Needless to say, I’m sick about it — but it’s probably a lesson I won’t have to learn again. When it comes to many things in life, single-tasking beats multi-tasking, hands down. Even when we know better, just “knowing” isn’t enough, unless we live by our knowledge!

        1. I am very sorry to hear this. It’s no consolation, but I think it happens to most photographers. If you haven’t done anything by accidentally deleted the photos from the card, you should be able to get a computer store to restore the photos. Worth a try at least.

          1. If they’d made it to the computer, I’d be all set, because I have automatic backup of my hard drive. Unfortunately, I cleared the card — not remembering that I’d taken so many photos they had been divided into folders.

            I’m in the process of recovering — and I’ve already made plans to go back to where I took the photos this coming weekend. I know precisely where many were taken, and flowers generally stay in the same place. 🙂

              1. And you were right, Otto. I went to CNET and chose a program from among those they recommended. Then, I downloaded the program, and followed the instructions. The first time, I got about half of the photos. Then, I figured out how to do a deep scan, set the program working, and went to bed. Lo and behold, I have all my photos back this morning!

                I’m so glad I mentioned what I had done to you. Despite all I’ve read about various government agencies recovering this and that, and despite all I’ve heard about files being recoverable, I guess I never thought it was something that I could do. I am so happy, and so grateful to you for setting me straight!

  6. we have our gecko family back on our porch, so i was very unsuspecting that your frog wasn’t real. it looks real to me. glad you chose greyscale.

  7. One of the most important factors in creating photos and beautifully explained, Otto. I am currently taking a class at the SF Art Institute and this was the topic last night. Great post and terrific image of your frog. 🙂

  8. The photograph stands out, dear Otto… Loved learning about this technical issues. Your writing is “philosophical” if I can call it so… I couldn´t avoid thinking of Kant and his Subject of Knowledge when I was reading 😀 Wishing you a wonderful weekend! 🙂

  9. Bilden är fantastisk Otto, så skickligt genomfört. Som vanligt ett intressant och inspirerande inlägg.
    Att testa och leka med inställningarna och se vad som händer gillar jag verkligen.
    God fortsättning på helgen!

  10. Depth of field can be a tricky topic. I was recently trying to explain it to my niece. I didn’t do a very good job but I will be able to let her read this now. Thank you.

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