How to Create a Custom Bokeh

The first thing you may be asking is what the hell does Bokeh mean?
The word ‘Bokeh’ comes from the Japanese word Bokashi which means ‘to blur’. The use of the word Bokeh in photography terms can mean areas of a photo which are not in focus due to being beyond the focal point – (this does not mean that a blurry, out of focus, poorly shot photo can be described as having nice bokeh).

Creating the Custom Bokeh

This was my first attempt at create a custom bokeh and had limited time to carry out the task.

I used the Canon 50mm prime lens as it has a very low aperture of f/1.8, ideal for blurring out the background.  I used the lights on the Christmas Tree as the blue background and a seasonal candle to act as the foreground.

Without any adjustments to the camera, with the aperture set to f/1.8 you get nice circular Bokeh in the background. You can see the lights in the background are well out of focus and are now circular soft blobs of light.
The next step is to create an interesting shape , i.e. custom bokeh, out of the lights in the background.

Creating Custom Bokeh, Aperture Shapes

You will need some stiff card, which sill completely cover the lens. You will also need a sharp blade or scissors to cut out the shape in the card.

I cut a heart shape in the centre of the card using a scissors and then fitted it over the lens and re-composed the photo.

Some Bokeh Tips :

  • Don’t cut the shape too large, an optimal size is about 10mm.
  • You will need to be able to control the aperture, so that it is as low as possible, so do not use AUTO mode. Aperture priority or Manual Mode will be required.
  • Ensure the card covering the lens (the card you cut the shape into) is centered and does not leave any light leak into the lens as this will reduce the effect.

By cutting the heart shape and covering the lens, all light entering the camera does so through that shaped aperture. Therefore all bokeh lighting in the background is shaped to the shape of the aperture. Therefore cut a star shape, all lights appear as a star and so on…

The result of my custom bokeh experiment is as follows.

Creating Custom Bokeh, Aperture Shapes

The next test of custom bokeh will be outdoors / street scene and I will post the results here!

If you have any comments or questions pop them below…