You can take your creative control of the aperture a step further by making your own custom shapes that alter the look of blurred areas in your picture. To make your DIY device, grab a piece of black card or thick art paper, and draw around a lens cap or a filter that fits the lens you’ll be using. Once you’ve cut out this circle of card, cut out your aperture in the centre of your circle. You can use a stencil or a craft punch if you want a professional look, but hand-cut shapes enable you to get a unique look. Use a simple shape for crisp, defined edges, and start with a hole that’s 5-20mm in size.