Shallow Depth of Field using Long lens

There are several advantages of using a long lens. By long lens I mean focal lengths in the range of 100mm to 300mm. We are not talking about those expensive telephoto lenses, but the typical zoom lenses that come in as a Kit lens.

Of all the advantages of using the long lenses, there are 3 primary usages, they are

  1. Obtaining shallow depth of field and Compression
  2. Field of View
  3. Perspective

In the following posts I am going to explain about of them. But let us start with the first advantage of using long lens – Shallow Depth of Field.  I will explain about compression in a separate postThis attribute of a long lens (or zoom lens) is not often talked about. Once we understand this concept, we can use this as a tool to our advantage. By the way, please note I an calling them a long lens and not a Zoom lens. If we only think of it as Zoom lens, then it makes you anchored in one place and wanting to zoom everything you see.

Most of the times we look at a picture with soft, creamy background and sharp foreground subject and think WOW, that should be a professional lens and say, If only I had that $1000 lens. Well, that is not true. We can get absolutely stunning images using just our kit long lenses.  Let me explain you how….

When you compose a picture, be it portrait, landscape, macro or any type of photography, first you will decide what is going to be the primary subject. Then you decide on how much importance you want to give to the subject in your frame i.e how much of your frame will that subject fill in.  Once you decide, then compose this picture in your view finder.


Take a look at the first picture here. This picture of the rusty nuts on this bridge was primarily taken to demonstrate the use of long lens to obtain a shallow depth of field. The gear i used here is a SONY NEX 6, with a 18-200mm lens. This is not a kit lens. But this can be demonstrated using a 55-200mm kit lens. The point here is not the gear, but the technique. So stay with me here.

As you can see the first shot is a slightly wide angled shot, i was standing about 6 ft away from the subject and zoomed in about 55mm on the lens.  The nuts are relatively tight enough, but not entirely filling the frame. But pay attention to the background and the other nuts behind the front two. Most of the nuts behind the front are sharp enough and you can see a lot of details in the background. This is typical shot we all take.

Camera Settings – Manual mode, F6.3, ISO 100, 1/15s, Focal length 55mm.


Now I decide to zoom in tight to the subject. Still I am standing about 6 ft from the subject. Same Aperture, F6.3. Focal length 120mm. In this picture, the nuts fill a good amount of the frame. But the nuts in the background are still slightly sharp (or not that blurry). I want the viewers eye to be on the first nut and then the nuts in the back and background melt away (out of focus or blurry). By now you would be thinking, yeah this is why we need those lens that can be wide open like F2.8 or lower.  Let me tell you, you will not need those fancy expensive lenses.

Here is where you need to do something outside your comfort zone of your zoom lenses. Zoom lenses, does not mean you always stand in on position or distance from your subject and zoom in or out. You can use your legs and move away from the subject or close to it.

For the third picture, I know i want to keep the front nut filling the frame. I did not want to change it.  I zoomed the lens all the way to 200mm. if i stand the same distance as before 6ft and zoom to 200mm and take the picture, i would certainly be cropping a bit of my subject and make the front nut too big in the frame. But i want to keep it the same size in the frame, you know why? Because, I have already decided on the composition and do not want to change it.

So now, how can i keep the composition same and zoom all the way to 200mm? You are right, use your legs and step back.  From 6ft, i went to about 11 ft from the subject. I carefully composed the picture to be similar to the previous picture. Bingo, my composition is perfect. But take a look at the background, there is some beautiful BOKEH  in the background and the nuts behind the first one have fallen pleasingly out of focused (or in layman terms BLURRY).


To me this is by far the best way to use a long lens. Fill the frame with your subject, use your legs to walk far enough to maintain the composition. You can obtain stunning soft background, but filling the frame and let the long lens compress the background and renter soft and creamy. Please keep in mind, we did not achieve soft background by opening up the aperture, we maintained the same aperture F6.3. You can achieve this same effect by using the moderate apertures up to F8 or slighty higher. Just fill the frame and compress the background by zooming in. That is all there is to it.

Let us quickly recap the steps we need to do get those creamy backgrounds

  • Carefully decide on the composition in your mind.
  • Zoom to close to the maxmium allowed on your lens
  • step back away from the subject, to accomplish the same composition you thought of, filling the frame with your subject
  • Click away 🙂

Here is a example of this technique employed to take a portrait of my son :). Look at soft background. This makes the foreground subject really pop!



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