Materials
Black plastic cocktail straws
PVC Insulating tape
Sunshade of the telescopic sight (scope) you want to make stealthier
A helping hand
A sharp serrated knife

My box of 400 straws could make at least 15 filters assuming each straw is 3 times longer than the filter depth and a bunch of 80 straws compressed matches the inside diameter of the sunshade you're protecting. Total cost = your time + about 6 dollars for 15!

If you have a choice, I would choose larger diameter straws than smaller, because intuitively this improves the light transmission (there will be less interstitial points with larger straws which should allow a better ratio than smaller straws).

There is another trade off in the length of straws (equates to depth of filter). The longer the straws, the narrower the acceptance angle but perhaps the darker the picture (it's not easy to ensure they are exactly inline or slightly skew. The shorter, the less this matters). I have settled on about 15mm depth which seems to give good results.

Camera Sony HDR PJ260V
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