Fujinon XF 23mm F1.4 Lens Review:
Landscape Astrophotography
Landscape astrophotography – the combination of a night
landscape with a starry sky – has gone mainstream. It seems the catalyst was
that iPhone 6 background showing the Milky Way over a Norwegian mountaintop.
You can increasingly do landscape astrophotography with
ordinary kit, but you still need a fast lens – ideally a wide-ish angle prime with really good edge performance and the
ability to focus perfectly on infinity.
Some of the best consumer cameras for use in low-light are
Fuji’s X series which use the innovative X-Trans sensor. Compared to a DSLR they are all small and
light for travel (‘cos let’s face it, most of us need to travel to do this kind
of photography) and have low noise and high sensitivity.
But which X-series lens should you buy for night landscapes?
The obvious choices for landscape astrophotography are the 16mm and 23mm XF
F1.4 lenses. Both are relatively expensive, fast primes; both are made in Japan
and promise those all-important (pseudo) manual controls. Here I take a look at
the first to come out and arguably the most general-purpose – the Fuji XF 23mm
F1.4.
Note: All the example images below
are straight from the camera. Apart from cropping I have done no
post-processing of any kind.
At A Glance
|
Lens |
Fuji 23mm
F1.4 XF R |
|
Type |
Prime |
|
Mount |
Fuji
X-mount |
|
Aperture
range |
F16 – F1.4 |
|
Size |
72mm x
63mm |
|
Weight |
300g |
|
Focus |
Autofocus
with pseudo-manual override |
|
Max
exposure time for landscape astrophotography |
8-13s
(minor star trails start from 10s) |
Data from Fuji/Me
What’s In the box?
Fuji include
end caps (quality items, but expensive if you lose them), a lens shade and a
strange cloth-with-pocket for cleaning and ‘wrapping’ the lens.
Design and Build
If you’re a newcomer to Fuji’s X-series lenses, the first
thing to understand is that there are two basic lines: CF and XF.
The CF lenses are largely plastic and made in China. They
look a bit cheap and insubstantial, but optically they are pretty good.
Then there are the XF lenses like the 23mm on review here.
These look very similar, but are all-metal, Japanese made and are much higher
quality. Don’t be put off the XF lenses
by the plasticky kit lens that came with your camera!
The XF 23mm is a beautifully made thing, the equal of any
Zeiss or other high-end lens in terms of build. Coatings are top quality and
mechanical build quality is of the highest order too. For such a fast lens,
it’s also quite small and light and doesn’t feel overbalanced on my compact
XM-1 body; that’s good because a 23mm lens on an APS sensor approximates to
40mm on a full-frame camera, so this is an ideal general-purpose lens.
At first glance, the XF 23mm appears to have old-fashioned
mechanical controls. There is a proper aperture ring with beautifully weighted
click-stops that give two intermediate apertures between the major ones.
The focusing ring looks like a manual one as well, with
proper distance settings and defined travel, but it’s not mechanical – it
actuates the autofocus motor. Nonetheless, it’s very precise (much more so than
many), if slightly noisy. Vitally for
night use, it has a proper infinity setting (and you can set it slightly past
infinity, if you need to). It also has a Vernier scale to show you depth of
field for each range and aperture setting, which might come in handy if you’re
trying to juggle aperture and depth of field to include closer subjects in that
astrophoto.
In Use – Daytime
I am not going to say much about daytime use because this
lens has been widely reviewed. Suffice to say it’s excellent, producing wide,
flat, sharp and detailed images. The high optical quality mean it still works
well at the full aperture of F1.4, remaining crisp and easy to focus with no
softness. The wide aperture comes in very handy for interiors and other
low-light conditions where you don’t want flash and allows for a very shallow
depth of field (for this focal length) if you need it.
The only daytime issues are a little more chromatic
aberration than I would like under high-contrast conditions and rather slow, noisy
autofocus (though I mainly focus manually using live-view anyway).
I find that the small size of the lens and camera are a real
bonus. I take this setup with me much more than I do my full-frame DSLR.
Below are a landscape photo and a 100% crop of the left hand
edge at F1.4.
Bryce Canyon landscape at F8, ISO 250
A different image, cropped to show the left corner at F1.4:
clear and sharp
Night Lane: 13s
at F1.8 ISO 2500 with Fuji 23mm XF lens, taken in b&w
In Use – The Night Sky
The first thing to note is that getting good focus, using the
camera’s magnified live-view, is easy with this lens, like a manual lens and nothing like many autofocus lenses where you
twirl the ring back and forth but never seem to get it quite right.
I really like being able to set the aperture on the lens too
and the click-stops are very positive. This is much easier in the dark than
trying to do it with a screen-based menu where you can’t find those tiny
buttons or thumb wheels.
On an APS-C camera like the Fuji CSCs, 23mm is roughly the
equivalent of 40mm full-frame. This isn’t as wide-angle as I would like for
landscape astrophotography, but nonetheless it is wide enough to get some
interesting combinations of Earth and sky if you compose carefully. But is it
fast enough to allow reasonable exposure times at fairly clean ISOs before star
trails start (the longer focal length the lens, the shorter the exposure time
before trails become apparent)?
At a focal length of 23mm, we need to be able to get exposure
time down to below 15 seconds to avoid star trails, whilst keeping the ISO at a
level that minimises noise. Is this possible with an X-Trans camera? The short answer
is ‘yes’, as you can see from the photo above.
The example shots were taken with an XM-1, which has
basically the same sensor and engine as other X-series models, so these results
should apply to your XT-2, XT-10 or X-Pro2 etc.
An exposure of about 10-13s yields lots of nearly pin-point
stars centre field and some nice nebulosity and Milky Way in a dark sky too. It
requires an ISO of 1600 to 3200, which gives a reasonable noise level in these
cameras.
Though the lens does basically work for astrophotography,
there are problems. Though corner darkening and astigmatism aren’t the issue
they are with some lenses, the edges (and especially corners) of the field show
quite a lot of coma. During the day, the XF 23mm seems sharp to the edge with
very little fall off in image quality. But at night, stars (especially bright
ones) become noticeably distorted off-axis. If this was a much wider angle
lens, you could just crop the edges, but there isn’t enough field width for
that for most shots.
The other negative is that zooming in on brighter blue or
white (O-A) stars shows quite a lot of violet bloating due to chromatic
aberration. This is a problem in the daytime too, though post-processing may be
able to fix it.
Due to the chromatic aberration, landscape astro’ photos can look better in black and white due to
that false colour around bright stars. In the photo above, the halos around
Orion’s sword stars are still evident but much less so than in colour.
The final thing to note is that at this focal length, star
trails actually start from as little as 10s when zoomed right in.
On the plus side, unlike a lot of cheaper lenses, the wide-open
setting is completely usable. However, stopping down to F1.6-F2.0 improves
things a little, but doesn’t completely fix that off-axis coma until you get
past F2.8, as you can see.
Below are a series of 100% crops of the star Betelgeuse in
the top left corner of the frame at F1.4, F2.0 and F2.8, showing the way coma
reduces as the lens is stopped down. Then for comparison a similar 100% crop
through the 24mm Samyang showing much lower levels of coma (though this lens
was faulty in other ways).
F1.4: 100% crop of Fuji XF 23mm image: a lot of coma on
Betelgeuse in the top left of frame
F2.0: 100% crop of Fuji XF 23mm image: coma on Betelgeuse is
still significant
F2.8: 100% crop of Fuji XF 23mm image: coma on Betelgeuse is
much lower at this aperture and virtually absent by F4.0
100% crop of
the Pleaides in the frame corner with 23mmFuji XF shows a lot of coma, even
stopped down to F1.8
Full width
crop of top third of Night Lane image (colour) shows off-axis aberrations are
not just theoretical – they do detract from astrophotographs
with the Fuji 23mm XF, even at F1.8
For
comparison, a 100% crop of the Betelgeuse in the frame corner with Samyang
24mm wide-open at F1.4. This lens is faulty (note strange star shapes),
but even so coma is much less than the Fuji’s
100% Crop of
Orion’s belt and sword with 23mmFuji XF at F1.8 and 10s – star trails and
significant chromatic aberration
Summary
The XF 23mm is a beautifully made, very compact prime with a
wide maximum aperture that’s completely usable and degrades the image very
little during the day. It largely solves the problem of providing both
automatic operation via the camera and precise manual control when needed, with
its pseudo-manual controls.
For daytime use it’s an excellent lens – sharp and detailed
across the frame, with lots of low-light potential and a shallow depth of field
with nice bokeh wide open. I really like the feel-like-manual controls,
especially the focus – I almost always focus this lens manually. The focus
control is perfectly accurate enough to get good focus on stars – something
lots of autofocus lenses struggle with.
So far so good. Unfortunately, the XF 23mm is a mixed bag for
night-sky shots. It’s fast enough to pick up the Milky Way and quite a bit of
bright nebulosity. Stars are nice and tight centre field. But there is quite a
lot of off-axis coma that’s very noticeable when you shoot star fields. There
is also quite a bit of violet bloating on bright blue-white stars. At this
focal length on an APS-C, star trails start above 8s.
I can really see why the XF 23mm is well-regarded. I have
used this lens a lot for the past two years and intend to keep it for daytime
use. But I can’t wholeheartedly recommend it for landscape astrophotography. It
works, but there are too many drawbacks for the price. You might be able to fix
some of the issues with software, but for astro’ use
I prefer the cleanest images to start with.
So far, however, I haven’t found
anything better. The
Samyang 24mm has huge potential, with much less off-axis coma, but the sample I
had was very soft and probably (hopefully!) faulty.
An outstanding daytime lens, I can only cautiously recommend
it for astrophotography, mainly due to too much coma. Having said that, I have
yet to find anything better at this focal length.
Milky way from the Grand Canyon: Fuji XF 23mm 10s at ISO 3200 F1.6
Buy Fuji XF 23mm F1.4 Here:
