The Canon Magazine 103
astro lenses
Centre Edge Corner2500200015001000500
Sharpness
f/1/8f/2.4 f/4 f/5.6 f/8 f/11 f/16f/22SAMyANG XP 14mm
f/2.4 £899/$999
This premium-quality manual lens from Samyang is a
direct competitor to the Irix 15mm
his 14mm f/2.4 is a great
fit for astrophotography,
having a 1mm shorter
focal length than the Irix
Blackstone on test, and
matching it for aperture. The
up-market optical design is
based on 18 elements in 14
groups, including two
aspherical, one hybrid
aspherical, two extra-low
dispersion and three high-
refractive index elements.
They’re all wrapped up in a
solid casing with sublime
handling. The rubberized
manual focus ring gives a very
assured grip and has an
unusually long rotational
travel with a particularly fluid
feel. This enables focusing
with extreme precision.
A key addition that’s
missing in the APS-C Samyang
lens on test is that this
full-frame edition has built-in
electronics. The aperture can
therefore be controlled from
the camera body, rather than
relying on a mechanical
aperture ring, and there’s
activation for the viewfinder’s
focus confirmation lamp.One minus point is that
there’s no weather-seal ring on
the mounting plate to guard
against the ingress of dust and
moisture. To be fair though, if
you’re photographing the
Milky Way, you’ll need clear,
dry and dust-free conditions.Performance
Image quality for
astrophotography when
shooting at the widest
aperture is better than from
the Irix 15mm and Sigma
14mm prime lenses on test.
Spherical and lateral
chromatic aberrations are
negligible, while coma and
astigmatism are minimal.FeATUres
VerdIc T
01
The optical path
includes high-tech
elements and
advanced coatings.02
The built-in hood
precludes a filter
attachment thread.03
The rubberized
manual focus ring
has long and smooth
rotational travel.04
Electronics enable
focus lamp
confirmation in the
viewfinder.05
Like in the other
Samyang lens on
test, the mount has
no weather-seal ring.FeATUresBUIld & hAndlIngPerFormAnceVAlUeoVerAll02040103T
e recommend an aperture of f/2.8 or wider for
astrophotography. The Canon, Sigma and Tamron zoom
lenses for full-frame cameras, and the Tokina zoom for
APS-C format bodies, all share this aperture rating. They also
have a ‘constant-aperture’ design, so f/2.8 remains available
throughout the entire zoom range.
The prime lenses on test are mostly a little ‘faster’ with wider
aperture ratings. In the case of the Irix and Samyang 14mm
full-frame compatible primes, they’re a third of an f-stop faster, at
f/2.4. The Sigma 14mm f/1.8 DG HSM | A is the outright fastest
lens on test, being 1.33 f-stops faster than the zooms, whereas
the APS-C format Samyang 10mm f/2.8 lens is no faster at all.
A bonus of faster lenses is that you can stop down a little,
making factors like corner-sharpness, vignetting, coma and
astigmatism less of a problem.How FAST?
For gathering small amounts of light from far, far away, a
wide aperture is all but essentialw
05