Sunday, 17 February 2013

Messing around with a pinhole lens

So, to tide myself over until my plans come to fruition (hopefully some news soon, I can't really say - or do -  anything until my employers know...), and to demystify my partner's new Dremel, I built myself a pinhole lens. It's not exactly rocket science and makes a fun project for a flu-ridden Sunday afternoon!

Step one is to find a surplus body cap - I've got three spares for some reason, so that bit was easy:

Next mark up the body cap on some tape - I used micropore because it was handy. I've marked out a square in the middle...

Drill the corners out...

Then use the cutting disc on the Dremel to finish the square (I'm wondering if the corner drilling was necessary, but I was kind of feeling my way through this!):

The final step is to make a pinhole in a square of aluminium foil and tape it to the inside of the body cap:

And it's finished! I particularly like the way that the construction technique shows off the workmanship and quality of engineering that goes into a lens like this...

So does it work? Well, sort of. The main issue is that the pinhole is too big - images come out very blurry. Apparently the key to a small pinhole is to make a bump in the foil and then gently sand off the peak of the bump, rather than just stabbing it with a pin. I got lazy and used the stabbing technique... but all in all I'm happy. I'm going to carry the lens in my bag anyway just because I can :D

Here's the results:

1 second exposure at ISO 100 seems to be the sweet spot (for completion's sake, the displayed aperture on the camera was f0.0)
Into the sun, with interesting diffraction/flare effects and a few mosquitoes. Who needs Instagram?