Atelier Bonryu(E)
pinhole photography
Laboratory: Pinhole Photography
Applications of Pinhole Photography
- Pinhole Mirror(2) -
To take photographs of the solar eclipse of June 22, 2009 and photographs of sunspots I prepared a pinhole mirror. But unfortunately it was cloudy on June 22 and I could not take a photograph of the solar eclipse by the prepared pinhole mirror. Moreover, as the sun seems inactive since last year (2008), there were observed few sunspots and I have not been able to take photographs of sunspots by the pinhole mirror.
As I could not prepare long dark corridor as Wood wrote I made a dark box surrounding an image screen to avoid the ambient light. The focal length of 6 m was employed by which the diameter of the solar image is about 5 cm.
Pinhole mirror
As a mirror of a pinhole mirror, I used a polished brass plate because it should be closely contacted to a pinhole plate and a surface mirror is desired. I prepared three pinholes with different diameters, i.e., 1.5 mm, 2 mm, and 2.5 mm and a zone plate for the focal length of 6 m with 19 zones. Shape of the zones is elliptic with the ratio of 1:
so that the angles of the incident and outgoing light to the mirror are 45 degrees to the normal of the mirror supposing the sun is right overhead.
Dark box for the pinhole mirror
Pinhole mirror and its dark box
On 22 July, 2009 in Mito it was thickly clouded with intermittent rain and there was not a chance to use the pinhole mirror for taking photographs of the solar eclipse. If it was fine, it was expected that the eclipse begins at 9:57:20, the maximum phase of the eclipse of 72 % at 11:13:43, and the eclipse ends at 12:29:54. Around 12:26 the thick cloud screening the sun got thinner and the last part of the partial eclipse was observed. Though I could not take a photograph of a pinhole image of the solar eclipse, I took a “conventional” photograph of the eclipse by Olympus E-510 with 18-180 mm lens.
An image of the sun by a pinhole mirror with the focal length of 6 m and the diameter of 2 mm projected to an image screen in the dark box. It was slightly overcast and it was not suited for taking a photograph.
An image of the solar eclipse taken by a conventional SLR with a glass lens (NOT a pinhole)
On 22 July, 2009 as it was thickly clouded and the pinhole mirror could not play a role. This photograph was taken by Olympus E-510 with 18-180 mm LENS (F11, 1/3200 sec) at 3 min before the end of the partial eclipse.
