Introduction: 10 Minute Sunglass Neutral Density Filter

About: I love building things and taking pictures.

Let me give you an overview of what happened so that you get why I made this up.

Basically, I needed an ND Filter. The next day. 

Here was my thought process:

1. What is an ND Filter? An ND Filter is a filter that basically lowers the intensity of the colors of a scene without messing them up. 

2. How can I make one without buying it?* Well, research on the internet showed that there is a way to do it with welding glass and another with polarizing filters. I did not have access to either and in such a short time, I couldn't get my hands on either. Shipping, sadly, is not instant.

3. Well, going back to the purpose of an ND Filter, how can I make one with materials on hand? Well, since an ND Filter basically a way to make things darker then...

4. What can dim the intensity of light? The first thing that came to mind were sunglasses. 

5. Will sunglasses work as an ND Filter? Luckily, this idea is testable as sunglasses are not that hard to come by. So, I set up a camera on a tripod and I took a meter reading (I went into Arpeture Priority and held the shutter button half way down). F36! Yikes! Then I placed on the glasses and took another reading F22! That is a drastic improvement. I repeated this experiment on different scenes and came to the conclusion that although not exactly specially made for a specific darkening amount, it works. 

6. What is the cost and time input needed? Well, I found the sunglasses at a dollar store and with tax it is just over a dollar. Not bad considering some others can go for about $50. 

*Making stuff is just so much better...

Step 1: Parts List

You will need:
1 Pair of sunglasses (I found the largest size diameter ones and took those. The bigger the lens in the center is, the better.)
1 camera 

Step 2: Added Bonus.

One of my friends mentioned that I could have cut the frames off of the lenses but then I thought, well, if I did that then the lenses might be more prone to break, plus, as I described in the second to last step, the frame gives you a place to tape onto. This is a pretty good alternative, though.

Step 3: Cut.

The first step is to remove the earpieces. Make sure to go as close to the lens as possible without touching so that it is as flat as possible. You can sand here if you want so that it make the filter flatter.

Step 4: Sever.

Next, on the bridge of the glasses, cut again with your cutters. Then take one lens and cut off the excess plastic so that it has the least amount of plastic possible. You might also want to trim off the part that you rest on your nose. you are now done.

Step 5: Tape and Photograph.

Now, tape it to the lens of the camera. If you have manual focus on your camera (an interchangeable lens, focus it first and then tape it because you don't want your tape to be positioned at a 45 degree angle and halfway through your shot for it to fall off (and of course I know because I have a first hand experience...

Set your camera into Shutter Priority (Tv on Canon or S on Nikon) and change to the shutter speed you want (the max on mine is 30 so I used 30 seconds.) and then hold the shutter button half way down. 

Step 6: Done.

That's how to build an ND Filter in an hour or so with a few bucks. This is nice and small so bring it along even if you have an ND Filter...double the f-stop lowering number. You can  make your shutter speed even longer! It's nice and light so it can fit in your pocket easily without any hassle.

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