Fujinon GF 23mm f/4 R LM WR lens

      Photo Review 8.8

      In summary

      The GF 23mm f/4 R LM WR lens merits a place in the kit of every landscape and architectural photographer who owns a GFX camera.

      Combining excellent performance with a reasonably versatile focal length, it is surprisingly distortion free. It’s also solidly built and extensively sealed, enabling it to be used in a wide range of conditions.

      Full review

      Announced in April 2017 shortly after the release of Fujifilm’s GFX 50S medium format camera, the GF 23mm f/4 R LM WR lens has a focal length equivalent to 18mm in the 35mm format and is ideal for landscape and architectural photography. The lens has a metal barrel and mount and is sealed to ensure weather, dust and freeze resistance. It can be used in temperatures as low as -10° C. This lens is supplied with a petal-shaped rigid plastic lens hood and a carrying pouch that has a drawstring closure.

      Angled view of the GF 23mm f/4 R LM WR lens, shown without the supplied lens hood. (Source: Fujifilm.)

      The optical design of this lens (shown below) consists of 15 elements arranged in 12 groups.  Two aspherical elements are included to control distortion and spherical aberrations, along with three ED (Extra-low Dispersion) elements and one super ED element to provide improved colour accuracy and clarity. A Nano GI coating has been applied to suppress lens flare and ghosting for improved contrast and colour reproduction.

      The optical design of the GF 23mm f/4 R LM WR lens, showing the positions of the exotic glass elements.(Source: Fujifilm.)

      Autofocusing is driven by a linear motor, which is fast and near silent in operation. Internal focusing maintains the overall length of the lens during focusing and ensures consistent optical performance across the focusing range. Rounded nine-blade diaphragm contributes to a pleasing bokeh quality.
      The lens is supplied with front and rear caps, a petal-shaped lens hood and a lens pouch with a drawstring closure. The lens hood has a locking button to keep it in position as well as for making it easy to fit and remove.

      Who’s it For?
      This lens can only be used on Fujifilm’s GFX cameras but owners of those cameras who want wide-angle coverage should find it worth a look. Covering the widest angle of view so far for the G-mount GFX camera system, the GF 23mm f/4 claims little-to-no distortion, along with sharpness from one edge of the frame to the other.

      This makes it best suited for landscape photography as well as for shooting architecture and interiors. It could also be used for photographing large groups of people but its size makes it conspicuous and its wide angle of view isn’t ideal for street and candid shooting.

      The minimum focus of 38 cm and 0.09x magnification aren’t really suitable for close-ups – unless the photographer wants to capitalise on the inherent distortion produced by all wide-angle lenses. Dust-, freeze-, and weather-resistance make it a good choice for use in demanding environmental conditions.
      The linear AF motor is smooth and quiet enough for this lens to be used for recording video footage and focusing is also nice and fast. The manual aperture setting provides added flexibility for tracking subjects at different distances.

      Build and Ergonomics
      With an overall weight of 845 grams and a barrel diameter of just under 90 mm, this is quite a large and heavy lens. Like other GF lenses it is made in Japan and robustly constructed with a metal barrel and comprehensive weather-resistant sealing.

      The front element is recessed, with the highest point in its bulging surface about five millimetres below the leading edge of the barrel. It’s approximately 40 mm in diameter and surrounded by ribbing that slopes inwards from the 82 mm diameter filter ring.
      A bayonet fitting for the supplied lens hood surrounds the outer edge at the front of the lens barrel. Behind it is a 10 mm wide ring that carries the full name of the lens, and then slopes inwards to meet the focusing ring

      This ring is 37 mm wide and almost entirely clad in thick rubber ridging. Because focusing is driven from the camera (‘by wire’) this ring turns through 360 degrees when power is off. However, it moves very smoothly and is quite responsive.

      A 14 mm wide unmoving section of the lens barrel is located aft of the focusing ring.  It slopes inwards for about 5 mm then flattens for about 9 mm where it carries a white line, against which the aperture ring is registered. The aperture ring is approximately 16 mm wide, with a narrow unridged band along its leading edge on which aperture settings are stamped in white. The remainder of the ring is plastic with moulded ridging to provide a secure grip.

      Marked aperture settings range in one-stop increments from f/4 at the right hand end to f/32 on the left, with unmarked 1/3EV click stops between them. Beyond the f/32 position are two extra marks, an ‘A’ position for selecting auto aperture and a ‘C’ position that lets you set the aperture via the camera’s command dial. An aperture ring lock release button is located on the ribbed section of the ring to enable these to setting to be used.

      The lens barrel continues for a further 15 mm before ending in the metal lens mount, which is surrounded by a narrow rubber flange that keeps dust and moisture out. Twelve gold-plated contacts inside the mount transfer signals between the lens and the camera.

      The petal-shaped lens hood attaches via a bayonet fitting and is secured by a locking button. It can be reversed over the lens barrel for transport and storage.

      Our Imatest tests showed the review lens to be very sharp in the centre of the field, with the highest resolution recorded at f/4. Interestingly, there wasn’t a huge difference in resolution between measurements made at the centre of the frame and those made at around half the way to the corner and three quarters of the way.

      Resolution declined slowly to f/8, after which the rate of decline increased slightly. Diffraction began to take effect at around f/11 but wasn’t an issue until about f/22, when images started to show noticeable softening, especially around the edges of the frame. The graph below shows the results of our tests, which indicate very good overall performance.

      Lateral chromatic aberrations were well controlled even in challenging situations although we found some coloured fringing in a few raw files when the optical corrections were disabled. Interestingly, our Imatest showed the test results for JPEGs were well down in the ‘negligible’ band, so the in-camera corrections are effective. The test results are shown in the graph of our test results below.

      As usual, we had to resort to raw files to evaluate vignetting and distortion. We found both to be surprisingly low for such a wide angle lens. Vignetting could be seen at f/4 but had largely disappeared once the lens was stopped down to about f/5.6, so it’s not a serious problem, especially since it can be minimised in JPEGs with in-camera corrections and addressed in most raw file converted when converting raw files into editable formats.

      Some barrel distortion was inevitable with such a wide angle lens on a medium format camera but, again, it was less than expected. Again, this aberration is easily corrected in camera for JPEGs and during raw file conversion so it’s not a serious problem.

      Autofocusing was moderately fast and generally accurate under a wide range of conditions, provided the correct focus settings were set in the camera. The linear AF motor was also very quiet, which is good news for videographers who want to use it on the GFX 100S camera.

      Like many wide angle lenses, the GF 23mm f/4 R LM WR lens is not ideal for close-up work, partly because of its 38 cm minimum focus but also due to its wide angle of view, which can introduce perspective distortions. Dare is required when framing shots to minimise perspective distortion. Bokeh was better than expected for a wide angle lens but not in the ‘smooth and dreamy’ category.

      Because it’s a fairly slow lens, there were times when we relied heavily on the IBIS in the camera we used for testing the lens. The weight of the lens can help to steady the camera and lens during hand-held shooting – but only if your shooting technique is up-to-scratch.

      We were able to obtain blur-free shots at shutter speeds as slow as 1/5 second with the GFX 50S Mark II. However, readers who plan to use it on a camera without stabilisation should factor in the need for a tripod in low light levels and for exposures longer than about 1/60 second – even with steady hands.

      We found the Nano GI coating to be quite effective at suppressing ghosting and flare, although there were times when they weren’t totally eliminated. The review lens could also produce some nice, 18-pointed sunstars when stopped down to f/22  or f/32– although because of the wide angle of view they were pretty small.


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      Picture angle:  99.9 degrees
      Minimum aperture:  f/32
      Lens construction: 15 elements in 12 groups (including 2  aspherical, 3 ED and 1 Super ED elements), Nano GI coating on front element
      Lens mounts:  Fujifilm G-mount
      Diaphragm Blades: 9 (circular aperture)
      Weather resistance: Yes
      Focus drive: Linear motor
      Stabilisation: No
      Minimum focus: 38 cm
      Maximum magnification: 0.09x
      Filter size: 82 mm
      Dimensions (Diameter x L): 89.9 x 103 mm
      Weight: 845 grams
      Standard Accessories: Front and rear caps, lens hood, lens pouch

      Distributor: Fujifilm Australia; 1800 226 355



      Based on JPEG files taken with the Fujifilm GFX 50S Mark II camera.



      Vignetting at  f/4.

      Rectilinear distortion.

      ISO 100, 1/450 second at f/7.1.

      Crop from the above image enlarged to 100% showing traces of coloured fringing.

      ISO 100, 1/14 second at f/11.

      Close-up at f/4, ISO 100, 1/250 second.

      Close-up at f/4, ISO 100, 1/400 second.

      Close-up at f/32, ISO 100, 1/5 second.

      ISO 100, 1/28 second at f/16.

      ISO 100, 1/20 second at f/16.

      ISO 100, 1/90 second at f/11.

      Sunstar; ISO 100, 1/5 second at f/32.

      ISO 100, 1/50 second at f/11.

      ISO 100, 1/25 second at f/5.6.

      ISO 200, 1/80 second at f/8.

      ISO 100, 1/250 second at f/4.

      ISO 100, 1/170 second at f/4.

      ISO 100, 1/40 second at f/9.

      Perspective distortion; ISO 200, 1/30 second at f/18.

      Perspective distortion: ISO 640, 1/17 second at f/14.

      Perspective distortion: ISO 200, 1/27 second at f/13.

      ISO 200, 1/80second at f/14.

      Additional image samples can be found with our review of the Fujifilm GFX 50S Mark II camera.



      RRP: AU$3999; US$2599

      • Build: 9.0
      • Handling: 8.9
      • Image quality: 9.0
      • Autofocusing: 8.9
      • Versatility: 8.5