How to use Focal Length and Background Compression to Enhance Your Photos

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How to use Focal Length and Background Compression to Enhance Your Photos

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One of the most common uses for zoom lenses is, as their name suggests, to zoom in on objects that are far away. These lenses are fantastic for getting close-up views of nature, architecture, wildlife, or anything else that might be little more than a speck to the naked human eye.

Some cameras like the Nikon Coolpix P900 let you get a close-up view of objects a few miles away. While this flexibility might seem like a rather tempting proposition for getting close to objects without physically moving yourself, there is another often-overlooked benefit of zoom lenses when taking portraits or other types of pictures with one clear subject in front of a vast spread of scenery – background compression. Understanding how this works, and how you can manipulate it, can transform your approach to portrait photography and give your pictures the type of visual boost that you might have always wanted, but never knew how to achieve.

background-compression-senior-photo

The basic idea with background compression is that you can take photos of something relatively close to you, such as a high school senior as shown in the image above, and bring elements of the background closer as well. This gives a more constrained feeling to the overall composition, and helps focus the viewer on your subject while not only bringing the background in, but often blurring it at the same time.

As an illustration of how this works, here are several photos of my dad taken at different focal lengths. Notice how he is framed similarly in each shot, but the background changes dramatically as I adjust the zoom on my camera lens.

18mm focal length, f/7.1, 1/80th of a second, ISO 100

I used an 18-270mm zoom lens to take these shots, and this first one (above) at 18mm shows my dad along with a massive background: utility poles, houses, trees, mailboxes, and all sorts of other elements make up the picture in addition to the subject. Take note of the car several hundred yards behind him, as indicated by the red arrow, and notice what happens as I change focal lengths, but keep my dad similarly framed.

18mm, f/7.1, 1/125 second, ISO 320

70mm, f/7.1, 1/125 second, ISO 320

Here you can already see several differences from the original image. The scene is now slightly claustrophobic with many of the elements along the perimeter of the original photo disappearing altogether. Mailboxes and utility poles have been brought closer, and notice how the same stationary automobile far in the distance has appeared to creep forward, and is now much larger. The background, in essence, is getting squeezed together or compressed.

154mm, f/7.1, 1/250 second, ISO 800

154mm, f/7.1, 1/250 second, ISO 800

At 154mm the vehicle in the background seems significantly closer, and various other elements such as trees and utility poles are now filling almost the entire frame. As I zoom in, while keeping my dad consistently framed in the shot, even the distance between the individual utility poles seems to be shortened, which further enhances the overall feeling of compression. It’s not just that things appear closer, but that the distances between all the elements of the frame look much smaller as well. This can be a powerful, and extraordinarily useful way to compose a picture, and you don’t even need a fancy camera or lens to do it. Most pocket cameras have optical zooms that can be used to accomplish the same effect.

270mm, f/7.1, 1/400 second, ISO 1600

270mm, f/7.1, 1/400 second, ISO 1600

In this final shot, the background elements virtually dominate the frame and almost overpower my subject. The vehicle just over his shoulder is about a quarter of a mile (0.4 km) away, though it appears as if it’s a mere stone’s throw behind him.

Background compression can be a good or bad thing, depending on the type of picture you are taking. The key takeaway here is to know what it is, and how to utilize it to get the type of composition you are going for. The longer your focal length, the more you will be able to add this sense of compression to your background. But, it also helps if you have a great deal of distance between your subject and the elements behind it. If my dad were standing a few feet away from something, like a tree or a brick wall, there would be virtually no compression at all, even with a very long focal length.

18mm, f/7.1, 1/80 second, ISO 100

18mm lens

18mm, f/7.1, 1/125 second, ISO 320

70mm lens

background-compression-dad-154mm-f71

154mm lens

background-compression-dad-270mm-f71

270mm lens

If the final example in the above series seems a bit extreme, here’s another set of images that show how background compression can be used effectively to enhance the overall composition, rather than overpower your subject.

35mm, f/2.8, 1/750 second, ISO 200

35mm, f/2.8, 1/750 second, ISO 200

This is a perfectly serviceable portrait, although I purposely left a bit too much space on the right-hand side in order to illustrate the compression concept. Shot at 35mm, with a wide aperture of f/2.8, the background is nice and blurry, the focus is clearly on the smiling woman, and the background is not too distracting or bothersome. However, re-taking the same picture with a longer focal length, leads to a much more pleasing picture all around.

85mm, f/2.8, 1/750 second, ISO 200

85mm, f/2.8, 1/750 second, ISO 200

The same compression shown in the first series of pictures is clearly evident here, though it is used to a much better overall effect. Even though the tree and cars create a background that is somewhat busy, shooting with a wide aperture blurred things out enough, that the focus is still clearly on the woman, while the background serves to add a bit of context to help put the overall composition in perspective.

One final note about compression: it doesn’t just work for foreground elements too as you can see in the following pictures.

35mm, f/11, 1/125 second, ISO 400

35mm, f/11, 1/125 second, ISO 400

I purposely shot this with a much smaller aperture in order to minimize the degree of background bokeh, lest compression be confused with blur. Notice how this woman is sitting squarely in the middle of the bench with plenty of room to her right, and about 50 yards (46 meters) between her, and the trees and cars in the background. Most of the picture is in focu,s which is a direct result of the small aperture.

85mm, f/11, 1/90 second, ISO 400

85mm, f/11, 1/90 second, ISO 400

Here the foreground and background have both been brought nearer to the subject. The trees and cars behind her are much closer, while the bench appears to take up almost no room on the woman’s right side. It might as well be little more than a chair in this picture, and yet, this is merely an illusion created by using a longer focal length while keeping my subject framed appropriately. Most of the picture remains in focus due to the small aperture, and you can clearly see that background compression is not always synonymous with background blur.

As one final example, here is the same woman, on the same bench, shot wide open at f/1.8 with my 85mm lens.

85mm, f/1.8, 1/1000 second, ISO 400

85mm, f/1.8, 1/1000 second, ISO 400

The overall compositional elements remain the same in this final image as the two above, except that I moved myself physically closer to the subject, while shooting at a very wide aperture of f/1.8. The background is severely compressed, and quite blurry, which leads to a rather pleasing portrait.

Background compression can be a bit tricky to understand, but if you play around with different focal lengths you should get the hang of it quickly. Then it’s just a matter of figuring out how to use it to your advantage to create the type of shot you want–especially when doing portraits.

Have you tried using this technique in your own photography? What other tips do you have to share about creative uses for background and foreground compression? Leave your thoughts in the comments below, and feel free to share any example images you have as well.

This week on dPS we’re featuring a series of articles about composition. Many different elements and ways to compose images for more impact. Check out the ones we’ve done so far:

Read more from our Tips & Tutorials category

Simon Ringsmuth is an educational technology specialist at Oklahoma State University and enjoys sharing his enthusiasm for photography on his website and podcast at Weekly Fifty. He also posts regularly to Instagram where you can follow him at sringsmuth.

  • John

    To clarify – it’s the photographer’s distance from the subjects – not the actual focal length – that causes this effect.

    You can see this effect even without a camera or lens. Stand at one end of a train or a long row of cars or houses. The object you are closest to appears much larger than the next, and the next.

    If you look into the distance at the objects further way – you’ll see the compression effect going on. It because they are far away from you.

    All the long lens does is fill the frame with it!

  • Doug Sundseth

    Absolutely correct.

    Compose with your feet; crop with your zoom.

  • Emily

    I really learned a lot from this article. Thank you!

  • Jonathan Richman

    Great article. Quick question: Why did you change speed and ISO as you used longer focal lengths in photos of your father? Thanks,

  • Good question, Jonathan. I used Aperture Priority so I could maintain the same aperture in all pictures, which meant that was not a variable in looking at how the final shots turned out. I used Auto ISO which is why that ended up changing, and when shooting at longer focal lengths you have to use a faster shutter speed in order to compensate for the vibrations that happen when shooting handheld.

  • I’m glad to hear it, Emily!

  • J

    Thank you for the informative explanation…I am just learning, and had the same questions, I enjoyed your article!

  • walwit

    I liked most the photo of your dad with the 18mm focal length, It gives mor info about where he is and consequently who he is, but without arguing anything is more pleasant to my eyes.
    But the woman looks great in that final image.

  • Thank you, Walwit. It’s interesting what people find pleasing in a photograph. I would not pick the 18mm as my favorite, but that’s the nice thing about photography–there is often no one correct answer and many things are left open to your own interpretation.

  • Well put together article that simply but effectively demonstrates the effect of focal length. Thanks Simon.

  • I’m glad to hear it Stephen. Thank you!

  • Ajidagba Ramon

    Why do I need to keep adjusting my ISO on different occasions.

  • That’s a simple question with a complicated answer. Here’s an article from DPS that might help though:

    http://digital-photography-school.com/iso-settings/

  • Right what Simon said – you want your shutter speed faster than 1/focal length so as you zoom in you need a faster shutter speed and consequently increasing the ISO is often how you will need to achieve that.

  • Michael

    As always, your articles are very educational and makes us better photographers. Thank you much Simon! The below Jonathan’s question could be answered with this law: Your shutter speed should be at or higher (faster) than inverse of your lens focal length. So when you shoot at 80 mm focal length, your shutter speed should be at least at 1/80 or much better off at 1/125 to avoid camera shake and as a result leading to a blur image. Now I have my own question that really bothers me all the time. Is there any relationship between the expose setting and the focal length of the lens? I’ve noticed from the two photographs of the woman on the bench that you did change your shutter speed from 1/125 at 35mm to 1/90 (increased the exposure a little) at 85mm keeping the rest absolutely the same (f/11, ISO 400). Can I safely assume for myself that when I shoot the same scene at the same lightening condition with two different focal length, I should increase my exposure whenever I change my focal length from low to higher? Well, it would be reasonable to say that my camera metering system would tell that but I just want to know that from technical side of photography.

  • David

    So, I know this may be a painfully obvious question or observation: to keep the size of the main subject constant while zooming to longer focal lengths, you were moving further back, away from your main subject, correct?

    Good article, by the way.

    David

  • Michele F

    I hope you get an answer David, because I have the same question! 🙂

  • Charlie Barker

    I have tried doing this using an 18-200mm lens on my EOS 7D, unlike your dad my subject kept getting closer too. How did you get dad to stay relatively the same size while the background got closer?

  • Good question, David and Michelle. Yes I did have to move much farther back from my dad in order to keep him the same size in the frame. At 270mm I was…oh, I’m just guessing here, but maybe 10 or 20 meters back whereas at 18mm I was only about a meter away. None of those photos have been cropped, so what you’re seeing is exactly what I got in camera.

  • Luis Hernandez Peña

    You must move yourself away to keep the subject the same size, while aproaching him with the zoom.

  • Charlie Barker

    Thanks I’ll give it a go.

  • Michele F

    Simon – thanks for taking the time to answer this in such depth. VERY much appreciated.

  • No problem, Michele! Good luck 🙂

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