Sky and Telescope - November 2015 - 66

Moving Pictures

MOVIE ASSEMBLY With whatever assembly program you use (Photoshop is shown above), choose a frame rate of 24 to 30 frames
per second. While you can render a clip at just 10 or 15 frames per second to make it last longer, the movie can look jerky.

ing what's known to time-lapse photographers as "holy
grail" sequences. These are time-lapses that transition
from full daylight or bright twilight through to dark
of night, perhaps with the Milky Way prominent. The
range of exposures can be as much as 18 to 22 f/stops or
"exposure values" (EV). That's more than can be accommodated by adjusting shutter speed or aperture alone.
There are several options for shooting a holy grail
sequence. One is to set your camera to Auto Exposure
Program and Auto ISO modes, then hope for the best
while the camera shoots away. A second method is to
meticulously monitor the shoot, adjusting the camera by
hand to increase the shutter speed, aperture, or the ISO
speed every few minutes.
A third method is to employ a more advanced
intervalometer (either a hardware unit such as the
TimeLapse+ or software such as GBTimeLapse) that can
"bulb ramp." These typically control the camera through
its USB port to automatically shift all three exposure
factors - shutter speed, aperture, and ISO - in small,
smooth steps over a sequence.

Processing Holy Grails
Whatever method you use, processing ﬁnal holy grail
frames requires special work, and software. One
processing setting won't work for all frames. Depending on how you shot the sequence, it might also exhibit
unsightly ﬂickering or jumps in brightness that need
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November 2015 sky & telescope

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Watch
an exclusive video on time-lapse photography
o
on our website at http://is.gd/UK5qcd.

to be smoothed out. The solution is a program called
LRTimelapse (lrtimelapse.com), which can work with
either Adobe Lightroom or Adobe Bridge.
To use it, you ﬁrst process several key frames at
points in a sequence where the brightness, color balance
- indeed any setting you can apply - need to change.
LRTimelapse then interpolates those settings over the
sequence, applying tiny changes to all the images' settings, creating a smooth transition from day to night.

Edit Your Masterpiece
As hard-won as they might be, individual time-lapse
clips usually aren't much good on their own. You need to
edit them into an inspiring movie, usually with dramatic
music, titles, and an overall theme or scenic subject. Use
"royalty-free" music clips to be sure you have the rights
to publish the music on the web.
Shooting enough footage, then editing it all together,
is no small amount of work, to be sure. However, the
payoﬀ is a montage that can captivate an audience emotionally as no still image can. It is truly moving. ✦
Contributing editor Alan Dyer is author of the eBook How
to Photograph & Process Nightscapes and Time-Lapses
(amazingsky.com/nightscapesbook.html).

http://www.is.gd/UK5qcd http://www.lrtimelapse.com http://www.amazingsky.com/nightscapesbook.html

Sky and Telescope - November 2015

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