Cell Phone Eclipse Viewer





Introduction: Cell Phone Eclipse Viewer

This is an update on an instructable I wrote for making a simple camera obscura. The same contraption can be used to take cell phone pictures of the 2017 eclipse next monday in the USA. I just tested it on our non-eclipsed sun and it works fine. Hopefully you still have time to build one - it doesn't take long! Note that your images will come out upside down, because camera obscura.


I made these little gadgets when I was a kid and had access to a darkroom and light-sensitive film, but here's my attempt to bring the camera obscura to the digital age, using my cell phone instead of film to record the image.

The result? Well, hum, zero in terms of the advancement of science - but I did manage to combine one of history's most advanced cameras with the most primitive, which is kind of neat. Anyway, it was a fun morning's project and might be useful for anyone out there teaching optics.

Step 1: What Is a Camera Obscura?

A camera obscura, or pinhole camera, is the earliest form of camera. It utilizes the principles of optics to project an image through a tiny hole, which functions as a basic lens. Early cell phone cameras functioned exactly the same way, incidentally.

Step 2: Start With a Box...

A pinhole camera is a box with a pinhole through one side. So you will need a box.

For an effective camera, there should be no internal reflections. Paint the inside black and seal up all the cracks (I used black electrician's tape). Paint the internal wall facing the pinhole white, to form your projection screen - or glue in a square of white cardboard.

Note that in the photo above, even without the pinhole or closing the box, the apartment opposite mine is already projected on the back screen through the rough hole I cut for the lens. Pretty cool. It gets better.

Step 3: Make a Pinhole

Take an ordinary washer and glue some aluminium foil to it. When it is dry, poke a little pinhole through the centre of the foil with a needle (or a pin, if you insist). This is your lens. You could just poke a hole through the box I suppose, but foil works better.

Glue the lens over the top hole you cut in the box (being careful not to damage your tiny pinhole).

Step 4: Mount the Pinhole

Cut a couple of holes in the box facing the projection screen wall on the inside. One of the holes will hold your lens, the other will be the opening you set your cell phone camera up to. The phone is mounted on the front of the box, facing backwards towards the projection screen.Yes, it is a bit clumsy.

Step 5: Add a Cell Phone

Attach your cell phone to the other hole (just below the pinhole) with tape or an elastic band so that the camera is viewing into the box towards the projection screen.

Now, cell phones are not good at long exposure photography, and the dim light projected by the pinhole is not easily picked up by the phone camera. You will need to download an app, but the good news is they are free. Search for a variant on "slow shutter cam". Then position your pinhole camera somewhere pointing at a scene with good lighting, and experiment with exposure times. Depending on your app, and the ambient light, it should take around 2-15 seconds. You are ready to make your first blurry historic image. Yay photography!



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    I like how the 17th century woodcut image you posted, actually looks like the guy might be trying to hold up HIS cellphone to snap a pic!

    This is great! You should use this to participate in Worldwide Pinhole Photography Day next April. I don't think I've seen anyone do anything like this.

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    I was not aware of Worldwide Pinhole Photography Day, thanks for telling me.

    Yeah, I love WWPD :) Plenty of people make a pinhole in their DSLR camera lens cap to get get an image, but your way opens up a new technique that I've not seen. I shoot on film with my pinhole cameras, but I'm definitely gonna try your method! Might be fun to see what could be done with a zone plate too.

    You can make a pinhole camera by poking a hole in a lens cap? And I thought I was cheating. Film all the way.

    Well, body cap might be more accurate - people take off the lens of the DSLR and then put on the body cap with a pinhole in it. You can even buy laser cut precision pinholes for your cap. Too easy! The last film camera I made was from a cereal box with a pinhole made from a aluminum soda can, but I'm definitely gonna try your brilliant method soon as I get some time :)

    "You are ready to make your first blurry historic image. Yay photography!"

    What a great tag line! As a hobbyist photographer I can really relate ha ha. Great instructable.

    1 reply