When you are creating outdoor spherical panoramas,
it often happens that the sky is really uninteresting, evenly
blue or gray. One solution for this problem is to replace the
boring sky with a new one, shot another day with fine clouds...
So I constructed this small Lego robot, adapted to my Coolpix
990 + Fisheye FC-E8 to help me stock a few sky photographs (Some
of them are available here)
This robot has two parts: a finger that press shutter
release when needed, and a screen that follows sun trajectory
in the sky. This screen helps to eliminate reflections in lenses
as shown below. One photograph cycle is performed every 10 minutes:
Press the shutter to wake up camera
(programmed to enter sleep mode after 30 seconds of
inactivity to preserve batteries)
Hide the shade below horizon and
acquire one photograph with the sun
Restore the shade between sun
and lens, and get another image without sun and artifacts.
The bright sun, reflected by the numerous lenses
of fisheye adaptor, creates several artefacts, difficult
to eliminate all.
These artefacts disappear when the sun is masked
The final image is obtained through blending
of these images.
The axle which supports the shade must be parallel to the
earth axis, and makes one turn per 24 hours, thus following
the sun. This requires some trimming of Skyshooter according
to latitude of your place and period of the year.
the CCD of your digital camera to direct sunlight
for a long time WILL
BURN IT. See
for example what happened to Romuald
who tried to create a sunset movie.
The LCD viewfinder of your camera gets its image
from the CCD, so this one remains unprotected between
shots. On the Coolpix 990, when you disable LCD
viewfinder, a shutter protects the camera, but this
may not be the case with YOUR camera.
Take care too of exposing the black body of your
camera to direct sunlight for extended period of
time, as it could get unreasonnably HOT. Anyway,
I can't be held responsible for any damage to your
SkyShooter and camera are placed on top of a
telescopic, three sections, 6 meter pole...
...and the pole is installed through a roof window
on my house first floor. This way, the camera is
above almost all obstacles and can see an unobstructed
entire sky. Only a few electricity pylons and my
neighbour's tree needed some touching up.
Here is the final result, after some Photoshop
tweaking. Other skies can be obtained here.
It's better to watch the weather ! Before I could
get my camera down of the pole, I got this image
showing the wonderful depth of field of fisheye
Detail showing camera position. Fisheye lens
must be fixed after inserting camera in SkyShooter.
showing screen movement in October, between 1 and
4 pm. The sky was particularly uninteresting that
by step construction instructions
Skyshooter can be built with - and only with - parts
included in Robotics Invention System (1.5 or 2) plus one rotation
sensor (included in Ultimate Accessory Kit, along with a remote
control - very useful too !)
LeoCad design files are available here.
- Tuning and setup
The axis which carry the shade arm must be parallel
to earth rotation axis. To do that, the angle L
must be equal to the latitude of your shooting site.
This angle can be adjusted by varying A, B and C
junction points. Take care to get point S on top
of fisheye lens.
SkyShooter must be oriented this way.
With SkyShooter correctly oriented, adjust rotation
of screen arm (depends on hour of the day) and length
of the arm (depends on the season) so that the shadow
of the screen covers center of fisheye lens. Then
start the program. The position of the arm will
be updated each time a new image is shot.
Of course, I made this adjustements in the garden,
with SkyShooter mounted on a tripod. When everything
is ready, I climb upstairs and install the thingy
on the pole (with RCX on to keep time)
Don't forget to disable the auto-off function
your RCX, and on the contrary set your camera to
the shortest auto-off to preserve batteries. And
read again the CAUTION
notice above !