Video Experiment: Build a Cheap Wide Angle Adapter

Inspired by this instructables how-to on using a door viewer to create a wide-angle lens for a still camera, I set out to create a low-cost, wide angle adpater for my camcorder. Here’s how I did it, and how you can do it too.

 

You’ll need the following:

 

- A door viewer

- A camcorder with a small lens and filter size

- A blank, protective filter for the lens.

- A video editing program capable of using multiple layers of video and masking.

- Strong glue.

- Patience

- For the advanced version, you’ll need Adobe After Effects Pro.

 

Now this technique only works with camcorders with small lenses: if the appropriate filter size is bigger than 25mm or so, the door viewer won’t fit over the lens. So if you’ve got a camcorder with a bigger lens, you’re out of luck. 

 

This is the door viewer I used: it’s a $7 model from Ace Hardware. There are plenty of others available, but get one that has a diameter as close as possible to the size of the filter. I like this one because it is brass (which looks cool) and has two parts, which makes it easier to put together.

 

The protective filter for the camcorder I used (a Sony DCR-PC109 (Review, Specs, $599.99)) came as part of a neutral density filter set, but you can probably pick up a protective filter of similar type at most video stores. Buy a couple: you should have a protective filter on your camcorder anyway to protect the front element of the lens from being poked and scratched, and the one we are using will be permanently attached to the door viewer.

Next, I glued the filter to the back of the door viewer (the bit that would be on the inside of the door, where you would look through it), using strong glue. I used some all-purpose adhesive I had lying around, but any form of superglue should work; just make sure it is strong, as you don’t want the door viewer falling off.

You should wait several hours for the glue to set before you try using ti and make sure it is properly glued on before you use it.

 

Now I can start taking the video. I set the zoom so that the circle of the image occupies as much of the screen as possible: the rest is wasted space that I’m going to blank out (in hindsight, for the example on the right, I could have zoomed in a little further to get more usable video). I also disabled the electronic image stabilization: the wide angle adapter will confuse it and make the whole video move, which will be a problem when we clean the video up.

On the right is a pretty typical raw frame of video from the camcorder with the assembly attached: the adapter didn’t interfere with the autofocus of the camcorder, and it didn’t make too much difference to the exposure, although you might need to adjust it manually: the dark areas from the barrel of the door viewer may confuse it. You also need to watch out when shooting into the sun: you may get reflections and the like from inside the tube. Dust and dirt on the door viewer will also show up, and the lens quality of the door viewer isn’t that great: remember, we are dealing with a $7 product here.

 

Next, I imported the video and processed it. I used Premiere Pro 2, but most video editing applications should be able to do this. I don’t want to see the tube around the video, so I created a circular image matte in Photoshop, and used the image matte filter to remove the parts of the video that show the barrel.

 

And I got this result: you get a near 160-degree view, which is a lot wider than the wide-angle adapters that the camcorder manufacturers produce.

 

I can also take it further: using the optical compensation plugin of After Effects Pro, I was able to take the circular video image and expand it to fill to frame to produce a rather interesting effect: especially the close-ups.

 

 

Here are a couple of sample videos taken with the adapter: you'll need Apple Quicktime to view them. The first is the unprocessed video: