Playing with Highlight Bokeh – A Fun Project

First of all, I should mention to you that the word ‘highlight bokeh’ is not a standard term. I just felt like using it (I’ll explain why), so here we go.

Hope you all know the meaning of the word ‘bokeh’. It comes from the Japanese word ‘boke’ which means ‘blur’ or ‘haze’. Just as the word suggests, we use that word to refer to the effect of things being out-of-focus aka blurry (background and/or foreground) in photography.

In photography, bokeh is the aesthetic quality of the blur produced in out-of-focus parts of an image.


Now let us look back at why I used the word ‘highlight bokeh’. Unlike other areas in bokeh, a light source or a strong reflection acts differently. They create certain shapes. See the below image.

Highlights in Bokeh
Highlights in Bokeh

It is clearly visible that the highlight spots in the bokeh have created hexagonal shapes, while other areas are just blurred. This is what I call highlight bokeh.

The Shape of Highlight Bokeh

The next question that arises is, how the highlight bokeh get their shape? You may have noticed that it is not always hexagonal like in the above image. The answer is ‘aperture’. Highlight bokeh gets the exact shape of the aperture. This is discussed in the article ‘What is Aperture? – Understanding the Basics‘ also.

So the camera which has taken the above image has a six-blade ‘iris diaphragm’. That is why the shape of the aperture has become a hexagon. If you pay enough attention you will note that the sides of the hexagon are not straight. It is just because the blades of the diaphragm are curved. Now, look at the below image.

Highlight Bokeh

This one is taken with my NIKKOR 50mm f/1.8G. You can see that the highlight spots are heptagonal here. It is because that lens has a seven-blade iris diaphragm.

seven blade iris diaphragm
Seven Blade Iris Diaphragm of NIKKOR 50mm f/1.8G

Just like that the highlight bokeh can be pentagonal, octagonal, nonagonal or any other shape (in non-iris diaphragms) according to the aperture’s shape. The next question now is, how can the highlight bokeh be in circle shape some times.

Circle shaped highlight bokeh

Here you can clearly see that the spots are almost perfect circles. And to make it more confusing, the above image has taken with the same NIKKOR 50mm f/1.8G lens. So how come they be round?

It happens when very wide apertures are used. Because the iris diaphragm blades are curved and due to their mechanism, the aperture turns to an almost perfect circle from an almost perfect polygon as the aperture is increased (f-number decreased). And the above image is taken at f/1.8, so the aperture is almost a circle, thus the highlight bokeh also.

What if We Manipulate the Shape of Aperture?

Now comes the fun part. If the highlight bokeh takes exactly the same shape as the aperture, what if we change the shape of the aperture somehow? The highlight bokeh shape must also change, right? And of course, it does. But how can we do that? Do we have to dismantle the lens and reach the diaphragm to do that? No, we don’t. It is pretty simple. Let us see how we are going to do that.

These are the supplies that are needed for this project.

  • a black (or any dark colour) paper
  • a pencil or a pen
  • scissor
  • craft paper punch (preferably)
  • some small light bulbs or a bulb string
  • a backdrop if you prefer
  • some objects like little dolls, action figures or fairies and some ornaments (as per your liking)
  • camera with lens
  • tripod (not compulsory)
  • lens filter
  • continuous lights or flashlights

Let’s Begin the Project

Step 01

Draw some circles on the black paper by placing the inner side of the lens filter on the paper. Cut those circles out through the inner side of the drawn line. Because circles must be slightly smaller than the inner ring of the filter to fit inside it. But, make sure the circles are not too smaller, because they may turn to sides if they are.

Step 02

Cut some shapes in the middle of the circles with the scissor or craft paper punchers. If you can use craft paper punchers, the outcome is neat. But if you are good at crafts and you have steady hands, you can just cut them with the scissor.

DIY Bokeh Effect Filters

This is how I have done it. I cut them by the scissor, so they are not perfect and not symmetrical. I folded the circles into two and then cut them. It is easier. Without doing all this, you can buy these kinds of ready-made bokeh effect kit online. But you know, it is much fun when you ‘do it yourself’.

The most important thing is that the cut shapes should be smaller than the largest aperture (in the lowest f-number) of your lens. Normally we use the largest aperture in this kind of situation. And the cut shape should be smaller than the aperture, to the shape to act as the aperture instead of the lens’ aperture. If the shape is bigger than the aperture, it serves no purpose since the highlight bokeh will take the shape of the lens’ aperture. See the below diagram.

So if the cut shape is larger than the aperture, the effective aperture will be some useless shape (as shown above) or just the shape of the real aperture of the lens.

Step 03

Next, you have to set up the scene using dolls, action figures, fairies and ornaments for the shoot as you wish, with what you have in hand. And then place the light bulbs or the bulb string bit behind the created scene to make sure they stay far out of the depth of field when the subject is focused.

Step 04

Set up the camera on the tripod. Place the camera close to the scene to make the depth of field shallow. It will easily create highlight bokeh from the lights behind.

Step 05

Place a cut circle you have created in front of the lens and put the lens filter on. Make sure the paper circles are free from dust or any other substance before placing them in front of the lens.

Step 06

Let the fun begin. Shoot with different circles and different scenes to create unique and beautiful highlight bokeh.

The Highlight Bokeh I Created…

As I told you earlier the asymmetry of my shapes is visible. And you should note that the spots in the middle are in good shape, but the ones close to the edges are kind of deformed. They are a bit curved from the sides. That is the phenomenon I mentioned earlier with the diagram. Even though the cut shapes are smaller than the aperture, when the light comes from extreme angles, they get affected again by the original aperture. The smaller you cut to shape, the lesser you face this problem.

So this is how it is done. I seriously hope you would try this in a free time. Feel free to leave a message if you need anything to know more.

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