Stenopiac image just means pinhole image.
While pinhole images can look fairly sharp, they can't match the
sharpness of a lens. The optimal pinhole for an 8x10 inch camera can
resolve about 5 lines per millimeter, which will look sharp as a contact
print. A good lens can resolve 100 lines per millimeter.
The optimal pinhole for a given projection distance is a tradeoff
between the size of the geometrical beam passing through the hole and
the size of the diffraction disk that any hole produces. The diameter of
the optimal pinhole only increases as the square root of the projection
distance.
For a 10 meter projection distance, the optimal pinhole is only 3.6 mm
in diameter.
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On 2020-04-08 12:04, Dan-George Uza wrote:
Hello,
I'm a big fan of meridian lines inside churches and I know these are sort of camera obscura sundials.
While I understand the geometry behind pinhole camera projections I can't seem to find any help on how the solar image forms after the rays pass a sizeable aperture nodus (for example a vertical 25cm nodus projected onto a wall 10 meters away) and how the ratio of hole size vs. projection distance affects the size and fuzzyness of the final projected image. So what's the geometry behind that?
PS: Some sources refer to the projected image as "stenopaic image". Is this universally acceptable? --
Dan-George Uza
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