In this article, I’ll give you some ideas and tips on how to use a prism to make some really cool and creative photo effects.
Have you ever seen the beautiful rainbows dispersed by hanging suncatchers and wondered, how would that look in a photograph? Unfortunately, the small prisms used on most suncatchers don’t fill enough of the camera frame to render a detailed image. But where there’s a will, there’s a way!
Triangular prisms, usually found in college science labs have become an increasingly popular tool for adding beautiful reflections and light to a photograph. Plus, because prisms are small, they are easy to pop in a camera bag, ready for your next shoot.
You may be familiar with triangular prisms from high-school demonstrations on the characteristics of light. The physics goes something like this – when a beam of light (made up of different electromagnetic waves with varying wavelengths) hits a piece of glass straight-on, the light passes right through it.
However, if the beam of light comes into contact with a glass surface at an angle, the wavelengths bend, which is a phenomenon called refraction. Then, when the beam exits through the other side of the prism, the wavelengths bend again. The amount the light bend depends on the wavelength itself. Red bends at one angle, and violet bends another and so each color is dispersed into the rainbow we see when we look through a prism.
As photographers, we exploit the inherent properties of light whenever we take a photo. The assembly of glass elements in camera lenses directs light from a scene, translating it to the digital sensor. But by adding a prism into the mix (in front of the lens) you can introduce some interesting creative effects to your photographs. Light that would usually meet the outer lens element first, hits the prism, dispersing the light before it’s directed into the camera.
What you will need
- A camera
- One triangular prism
- A lens cloth
This project only has two ingredients – a prism and a DSLR camera. For this project, I used a triangular prism I purchased on eBay for a few dollars. A prism that can be manipulated with one hand is ideal. My preference is one that is approximately 3″ x 1″ (8cm x 2.5 cm). Keeping a lens cloth close by is useful for fingerprints on the glass that can show up in the image.
Using a prism to create interesting effects in-camera requires a little trial and error and a bit of co-ordination. Holding the prism over the front lens element is the easy part. It’s getting the effect right that’s a little fiddly. I’d recommend using a tripod as it can be a bit vexing having to juggle the camera in one hand and the prism in the other. I would also recommend using Live View to give you an accurate indication of what impact the prism is making, without being blinded by wayward reflections from the sun streaking through your viewfinder.
If you’ve ever shot through glass materials before, you’ll know that your autofocus can really start to struggle. First, focus the camera on your subject using autofocus, then switch to manual focus mode. That way, the subject in the background will already be sharp, without having the camera flail around trying to focus on the prism itself.
Slowly rotate the prism, monitoring the effect on the LCD screen. Angling the prism away from the lens, or changing your position in relation to the sun can also add different effects. Experiment with the distance between the prism and the camera lens too. When you find a reflection in the image you like, take a snap!
Now that you have the basics down, try changing up the prism! I am constantly switching between my triangular prism and a glass wine stopper I chanced upon in an op-shop. The hexagonal prism adds a greater kaleidoscopic effect but tends to distort the image more, so it’s fun to experiment and see what works best.
So pick up a glass prism and give this a try. Please share your prism photographs in the comments below.