Home

 

 

Fujinon XF 23mm F1.4 Lens Review: Landscape Astrophotography

Landscape astrophotography Ė the combination of a night landscape with a starry sky Ė 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 Ė 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 Fujiís X series which use the innovative X-Trans sensor. Compared to a DSLR they are all small and light for travel (Ďcos letís 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 Ė 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 Ė 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

Whatís 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 Ďwrappingí the lens.

Design and Build

If youíre a newcomer to Fujiís 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. Donít 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, itís also quite small and light and doesnít feel overbalanced on my compact XM-1 body; thatís 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 itís not mechanical Ė it actuates the autofocus motor. Nonetheless, itís 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 youíre trying to juggle aperture and depth of field to include closer subjects in that astrophoto.

In Use Ė Daytime

I am not going to say much about daytime use because this lens has been widely reviewed. Suffice to say itís excellent, producing wide, flat, sharp and detailed images. The high optical quality mean it works very 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 donít 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

100% crop of the left hand edge of a different image at F1.4

Night Lane: 13s at F1.8 ISO 2500 with Fuji 23mm XF lens, taken in b&w

In Use Ė The Night Sky

The first thing to note is that getting good focus, using the cameraís 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 canít 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 isnít 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 Ďyesí, 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 arenít 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 isnít 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 astroí photos can look better in black and white due to that false colour around bright stars. In the photo above, the halos around Orionís 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 doesnít 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 showing coma on Betelgeuse in the top left of frame

F2.0: 100% crop of Fuji XF 23mm image showing coma on Betelgeuse is still significant

F2.8: 100% crop of Fuji XF 23mm image showing coma on Betelgeuse is much lower at this aperture and virtually absent by F4.0

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 Fujiís

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 Ė they do detract from astrophotographs with the Fuji 23mm XF, even at F1.8

100% Crop of Orionís belt and sword with 23mmFuji XF at F1.8 and 10s Ė star trails and significant chromatic aberration

Summary

The XF 23mm is a beautifully made, very compact prime with a wide maximum aperture thatís 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 itís an excellent lens Ė 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 Ė I almost always focus this lens manually. The focus control is perfectly accurate enough to get good focus on stars Ė something lots of autofocus lenses struggle with.

So far so good. Unfortunately, the XF 23mm is a mixed bag for night-sky shots. Itís 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 thatís 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 canít 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 astroí use I prefer the cleanest images to start with.

So far, however, I havenít 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

 

 

Home