Creative aperture filters are strong black paper-like filters with a small hole of the desired shape. They are used in front of a lens to give special shapes to blurred dots of light present in the out-of-focus part of a photo. The example below is particularly great, taken from this website.
Below, a Dan Bracaglia picture, showing all Lensbaby creative aperture choices. A customizable set of blank filters is also available from Lensbaby.
The website from which I borrowed the above picture of a girl gives an idea to make a paper lens hood with a heart-shaped aperture. Unfortunately, his kind of design cannot be easily stored or brought with you in a camera case. That’s why I suggest to make such filters based on step-up rings, much like the original Lensbaby idea.
– A DSLR or hybrid camera. Point-and-shoot won’t work well.
– A fast lens. You won’t get good results with an aperture that’s not at most f2. I used the cheap Canon 50mm f1.8, which revealed itself to be a very good lens for the job.
– Some strong paper, construction paper or such. I used strong disposable paper plates (black ones from Halloween ). Obviously you’ll need some opaque material, preferably black at least on one side.
– A cutter tool.
– A step-up ring. You can either glue the filters on the ring, or not, so you’ll need at least one ring, more if you want to make permanent filters. I got some 52-55 very cheap step-up rings from Amazon for this purpose.
- In order to make a permanent filter you’ll obviously need to glue a 55mm paper circle to the step-up ring, so you should preferably make it a bit on the large side just to be sure to get it right.
- In order to make non-permanent filters, very useful if you want to experiment with all sorts of shapes, I found out that drawing the filter using the edge of a 52mm UV filter as shape somehow provided exactly the right size for a 55mm filter. The same way, the edge of a 55mm filter or ring will provide the right circle size to make 58mm filters, etc. Then, when you put the filter in the ring, the screw marks on the inside of the ring will hold it in place if the filter is nicely fitted.
I haven’t had the chance to test different sizes for the shaped holes in the paper filters, but logic would suggest that the wider the opening, the more light you get, the less sharp the edges of the shaped bokeh dots will be. Which means that in the example below, I get quite sharp stars because of the very small star-shaped aperture I chose for my filter (see above).
The dirty science
I made some tests with shapes of different sizes. It appears that a small shape will create well-defined background shapes from a small distance. Thus, this would be best for portraits. On the contrary, a large shape will need to be far away from the lens to create a complete image, and is most suitable for the outside, street lights and such.