My first Magazine Sky & Telescope - 04.2019 | Página 62

S&T Test Report by Alan Dyer
Sony’s Mirrorless Marvel
We put a new Sony α7 III mirrorless camera
through its paces on deep-sky imaging.
Sony α7 III
U.S. Price: $1,999.99; sony.com
What We Like
Low noise
Bright live-view screen
Low-light 4K movie mode
What We Don’t Like
Incompatible with most
control software
Sensor mask shadow
Edge glow in long
exposures
refl ex (DSLR) cameras revolutionized all
areas of photography, including astro-
photography. Today, a new generation
of cameras without refl ex mirrors lies
at the heart of another major change in
how we take pictures.
In the past fi ve years, Sony, not a
name traditionally associated with cam-
eras, set the bar in “mirrorless” cameras
for professional-level photography.
Established brands such as Canon and
tp The new Sony α7 III mirrorless camera can
do a fi ne job on wide-fi eld tracker images, like
this stack of eight 2-minute exposures at f/2
with
w the Venus Optics 15-mm, a fast, compact
lens made for the Sony E-mount. The Sony
camera’s tilting screen saves the neck and
back when framing and focusing sky shots.
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A PR I L 2 019 • SK Y & TELESCOPE
Nikon have only recently entered the
mirrorless market but are expected to
expand their offerings to the point that
the DSLR might soon become a limited-
edition camera.
Why Mirrorless?
So what’s the attraction? Removing the
refl ex mirror creates a shorter “fl ange
distance” from the lens mount to the
sensor. That, and the lack of a penta-
prism for an optical viewfi nder, makes
for a compact and lighter camera body.
The shallow fl ange distance also
allows manufacturers greater freedom
to design fast yet compact lenses that
are “native” for the mirrorless cameras.
However, by using the right adapter —
and there are dozens available — you
IN THE MID-2000s, digital single-lens-