How to Adapt a Door Viewer "Fish-eye Lens" on to a Full-size Camera

Step 5 Fitting on the Door Viewer

Now that the reducer has been shortened and filed off, you can fit the door viewer on and get a feel of what the the adapter is like with a unit.

Take the strip of cloth or paper towel, making sure it is no wider than the length of the door viewer barrel and wrap it around the barrel a couple times. Test to see if barrel will go through the narrow end of the viewer with a little resistance, but not so much that it jams halfway in. The best fit will be when the wrapped barrel goes in to the reducer with some twisting and will not fall out when the unit is turned on end. You should then be able to take out the door viewer again with a little effort.

Since I'm also using my door viewer on compact point and shoot, I don't want to mount it permanently in the adapter. You may want to make yours permanent gluing the barrel to the cloth with contact cement and then gluing it all into the reducer after that.

Tip: Depending on how you want it to fit, the door viewer barrel can be extended by unscrewing the lens portion from rest of the barrel. Just remember that the longer you make the barrel, the further away the lens will be from the lens of your camera.