How to Make A Lens-free Camera Obscura

I read once that the camera obscura has been known about for centuries and was observed when a knot of wood fell out of a plank and let a small amount of light into a room.  Based on that story, I did the following (all without any lenses, just like in the old days).

If you want to try this at home, here’s how:

1) Block off all light into a room (for anyone who has worked in a darkroom, it doesn’t have to be quite that dark — light can seep in and this will still work).  A small room with one window is easiest, of course.

2) Cut a small hole into whatever is covering the window with the view (about the size of a quarter worked for us).

3) Let you eyes adjust and see what you get. Move the hole (covering old ones) to change what is projected.

4) Take a photo (it’ll show you more than your eyes can see).   This one was done with an exposure of 30 seconds at f/4.0

Here is the very low tech device used to cover the window (leftover cardboard from the Halloween costume & duct tape).  No lens required!

Please post a comment if you have any luck with this.


You can see that the trees are now losing their leaves. This view was earlier in the day than my original post with great fall colors — things look pretty grey now.


Below is a more recent photo — all the leaves have gone now (11/27/07)


8 thoughts on “How to Make A Lens-free Camera Obscura”

  1. Hello Leo,
    Liked your pictures of your camera obscura.
    Have you tried looking to see if it is possible to view the stars at night ?
    I am researching ancient astronomers and their findings and would be very interested to know if this is possible.

  2. Nice work Leo

    Hi John, You would need a very large hole to allow enough light in to view stars at night, as the hole gets larger the image becomes more blurry which means you would not be able to see the stars unless you put a lens in which would be very expensive.

    It is probable that in the past astronomers used camera obscura to watch eclipses and view sunspots etc on the sun.


  3. Hi Tony,
    Thanks for your comments,I have tried looking at the sun’s image in a room with a “focal” length of about 12 ft (3.7M. The pin hole size being 1.0 mm dia and this gives very good resolution.I am very interested to find if it is possible to accurately compare the relative position of the sun/star over several days when observed at the same time of day/night.
    This can be tried in a spare bedroom but my wife and probably the neighbours are going to think that I am some kind of nutter !
    Merry Christmas to Leo from the UK

  4. Hi Leo,John,

    Any thoughts on making a larger camer obscura/solar viewer? I have a group of interested grade 8 students, and a SW-facing classroom with windows that I can darken. To allow for a larger image, I suppose I’d have to use a lens with a greater curvature, or go for a longer focal length (the room is 13m wide :)I would love to exchange ideas.
    Thanks, Dean

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