WWW.ASTRONOMY.COM 63— a really neat idea. You’ll likewise be
able to insert astronomy-related filters
as they become available.
As an added bonus, you can assign
custom functions to most of the Ra’s
buttons and its multi-function bar.
There’s also a ring with click stops for
the RF lenses and some EF adapters,
which allows you to make additional
adjustments. Being a nuts-and-bolts
kind of person, I chose to turn the multi-
function bar off. Because the ring can
only be activated when another button is
held down, this negates the chance of any
accidental movement.
While I was at the Advanced Imaging
Conference in 2019, I had the opportu-
nity to see more of the latest RF lenses
made specifically for Canon’s R-series
cameras. These lenses are wider than a
normal lens. And if they are fast, they are
also quite heavy. Although they canhandle being
attached to a tripod
or mount, I would not recommend going
on a hike with them. For daytime use,
my favorite lenses are the 24–70mm
f/4 EF with macro and the 70–200mm
f/4 IS EF. Both of these are used with an
adapter to allow for internal filtering, as
mentioned earlier.
The Ra does not come with a built-in
intervalometer, so to automatically shoot
continuous images, you’ll need to buy an
external one that plugs into the camera.
But if you are shooting three-minute,
dithered exposures (by slightly shifting
the camera between exposures), the
exposure time in bulb mode can be set
all the way to 60 minutes. No external
timer needed.
I should also say something about
how I prefer to image with the Ra. As
previously noted, the Ra has very little
noise. This means you can get by shoot-
ing just a single frame. But to get the
most detail out of the sky, nothing beats
shooting multiple frames. Through
experimentation I’ve found that longer,
low-ISO exposures are better than
shor ter, high-ISO shots. However, t his
means you’ll need some form of tracking
with a small equatorial mount, for
instance, or a star tracker like the Vixen
Polarie. I typically shoot three- tofive-minute exposures at an ISO of 800
to 1600 (depending on the target) and an
f-ratio of f/3.5 to f/4. Shooting wide open
records the worst the lens can perform
and usually leads to heavy vignetting
that must be dealt with after the fact.
I always shoot RAW images, taking
anywhere from five to nine exposures,
dithering between each. I then convert
them to Digital Negative Image (DNG)
files and import them into Adobe
Camera Raw (ACR) for processing.
Once I’ve processed the images in ACR,
I save them as 16-bit TIFF files and
import those into RegiStar, where the
files are aligned and combined — or
stacked — to create a master TIFF file.
Finally, I import the master file into
Photoshop for final adjustments and
enhancements.Better than a small step
The Canon EOS Ra is a giant leap for-
ward in astronomical imaging. Its com-
bination of high sensitivity, low noise,
and good resolution in a modern archi-
tecture is a true winner. Plus, the touch-
screen menus alone are worth the price
of admission. All in all, the camera is a
real joy to work with.Canon EOS Ra
Type: Digital single-lens non-reflex
Sensor: 30.3-megapixel CMOS
Format: Full frame (36 by 24 millimeters)
Resolution: 6,720 by 4,480 pixels
Processor: DIGIC 8
ISO range: 100 to 40000
Shutter speed: 1/8,000 to 30 seconds
Continuous shooting: 8 frames/second
Wi-Fi: Built in
Display: 3.15-inch vari-angle touchscreen
LCD
Dimensions: 5.35 by 3.87 by 3.32 inches
(135.8 by 98.3 by 84.4 mm)
Weight: 1.28 pounds (580 grams)
Price: $2,499.00 (body only)PRODUCT INFORMATION
camera
Tony H allas is one of the world’s top
astroimagers.Canon’s EOS
Ra sports a DIGIC 8
processor and a full-
frame CMOS chip. Its
shutter also closes when
the camera is off,
protecting the sensor.