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The
Starry Sky (December 14, 2006)
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| Canon EOS 20D, Sigma 12-24mm f/4.5-5.6 EX DG HSM, 30" f/4.5, iso 400,
tripod. Dolomites, Italy. |
The Three Peaks of Lavaredo are some of
the most famous mountains of Dolomites. In the first weeks of
october, I led two workshops in that area: from Misurina, we reached
the Locatelli hut. The hut is already closed in october, but there
is an alway open winter room for six persons, where we slept. The
first day was very foggy, but the fog gradually disappeared during
the night and when we get up, two hours before sunrise, the sky was
cloudless. The air was cold and clear. The light of the waning
crescent Moon was pretty dim, so the stars were shining
brightly...what a vision!
I mounted the Sigma 12-24 and the 20D
on my sturdy Gitzo 1548 tripod. The landscape was really dark so it
was really difficult to compose the photo...we turned off the
flashlights to get used to darkness. I choose to use the 12mm focal
lenght to include as much sky as possible into the composition, and
to use the zoom at its brightest aperture (the Sigma is f/4.5 at
12mm, while it is f/5.6 at 24mm). It was impossible to focus in the
complete darkness so I set the the lens near infinity...the 12mm has
a pretty wide depth of field even at f/4.5, so I had some margin of
error. I checked the sharpness in the LCD screen at the maximum
magnification and I adjusted the focus until the photo was in sharp
focus. The camera was set in evaluative metering, but in these
situations the meter don't give acceptable results, so I turned the
camera in M (full manual) mode. I begun by trying an exposure of
30" f/4.5 ISO 100, but the photo was pretty dark (I checked the
exposure with the histogram), so I set the exposure to 30"
f/4.5 ISO 400, and the image turned out correctly exposed. I could
have taken the same image with an exposure of 2 minutes at ISO 100,
but here I preferred to raise the ISO because I wanted to capture
the stars as points, not as star trails.
To get the best from this image, I had
to spend a little of time with Photoshop. First, it was necessary to
remove the noise - a dark scene photographed at ISO 400 is very noisy!
Then, I used the Layer Mask and the Levels to brighten up a little
the foreground, so the mountains are not just black silouettes, they
show a glimpse of detail. Last but not least, I applied a local
contrast adjustement in the sky to enhance the brightness of the
stars: I selected the sky and I applied
the Unsharp Mask with Radius 20 pixels and Amount 30%. With these
values, the Unsharp Mask enhances the contrast of the photo instead
of enhancing the detail (I don't recommend to use this technique
with all your photos since sometimes it creates artefacts, but is
some situations it really helps the photo).
Night photography is always a
challenge - but it is a neat experience, and some times the results
are very rewarding.
Do you have
comments or questions?
If you have comments or questions about this
article, feel free to ask in the Juza
Nature Photography Discussion Forum!
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