How To: DIY Solar Filter

NEVER LOOK DIRECTLY AT THE SUN, ESPECIALLY THROUGH A TELESCOPE, BINOCULARS OR A CAMERA WITHOUT PROTECTION. 
THIS CAN RESULT IN INSTANT AND IRREVERSIBLE BLINDNESS.

If you want to view the sun through a telescope, or photograph it using a DSLR camera, it is neccessary to either buy or make a solar filter. You can buy them in many places online, but they can be a bit pricey. I have previously made a filter for my telescope using Baader AstroSolar film, and it has worked perfectly (see here and here), but for this DSLR filter, I decided to try out Thousand Oaks Optical polymer film.

I purchased a 4"x4" sheet, as it was all I needed to cover the lens, but if you are making a filter for a telescope, you should definitely go for a bigger size. I ordered mine from amazon.co.uk, and it arrived really quickly, despite coming from Israel!

So to make the filter, I decided to use the end of an empty Pringles can, as it was the perfect size to fit over my lens. I cut the end off to about 4 inches. 

I then cut a hole in the base. I wasn't concerned about vignetting, as everything outside of the sun is going to be dark anyway, so I left a good cm edge around it, to hold the film in. 

At this point, you can sand down the edges if they are sharp, to prevent damage to your filter paper. I opted to cover mine in electrical tape. You then need to cut your filter paper to fit inside the Pringles can. This must be done carefully in order to avoid damage to the paper. The oils on your fingers can damage it, as can any tiny nicks or scratches, making it dangerous to use. Try to handle the paper as little as possible.

I then covered the outside and the base of the can with electrical tape.

The filter paper is then placed inside the Pringles can, and held in place using a circular piece of plastic (cut from a spare Pringles lid) and 4 pieces of strong card folded into an L-shape and then taped to the inside of the can. 

I'm using the Pringles lid as a pseudo lens cover.

In order to attach the filter to my camera, I taped some thick cardboard to the inside of the can, so that it fits tightly around my lens. I also punched two holes in the can, through which I tied some elastic bands, which will hold it very securely to my camera body. You *really* do not want this to fall off while you have the camera pointed at the sun, so it is very important to make sure everything is securely fastened together. 

I tried mine out this morning and it worked an absolute charm. 

Fingers (and toes) crossed for (relatively) clear skies!