The Fujifilm GF 45-100mm f/4 R LM OIS WR is the manufacturer's first attempt at a medium format zoom lens – two things that don't often go together. When they do, however, the stars can align for a very special optic indeed.
With its 35mm equivalent focal range of 36-79mm, this is as close to a standard zoom as you're going to get on a GFX camera, making this a valuable all-purpose lens on paper. And, when paired with the best medium format cameras made by Fujifilm, this has the scope to turn something like the Fujifilm GFX 50R into the ultimate walkabout powerhouse.
Mount: Fujifilm GF
Lens construction: 16 elements in 12 groups
Angle of view: 62.6° (wide) / 30.6° (telephoto)
Diaphragm blades: 9
Minimum aperture: f/32
Minimum focusing distance: 0.65 m (wide) / 0.82 m (telephoto)
Maximum magnification ratio: 0.13x (telephoto)
Filter size: 82mm
Dimensions: 93 (dia) x 144.5mm (length)
It goes without saying that the almost-standard-zoom focal length is the key appeal of the GF 45-100mm f/4, but there's plenty more that makes this lens special. Much like the Fujifilm GFX 50S and 50R, the lens sheds the traditional bulk of medium format photography equipment, resulting in a form factor not too dissimilar from a DSLR with a chunky zoom attached.
As its nomenclature suggests, the Fujifilm GF 45-100mm f/4 R LM OIS WR possesses two important traits: Optical Image Stabilization and weather resistance. The former delivers a claimed five stops of compensation, enabling you to shoot both at the telephoto end without wobble and to shoot handheld at slower shutter speeds to account for the f/4 aperture.
The latter offers dust and moisture sealing, as well as the ability to shoot in temperatures down to -10°C / 14°F, giving you a largely all-weather medium format imaging system.
Build and handling
While the lens really isn't small, at 144.5mm in length and weighing in at 1,005g, it remains a marvel that this kind of optical complexity has been crammed into a chassis that isn't really isn't large either. Again, Fujifilm's accomplishment in taking medium format from a bolted-down studio system to a street photography capable setup is quite remarkable.
The lens balances well on the GFX 50R with which we tested it, and the magnesium alloy construction gives it both the strength to withstand the rigors of professional shooting and the necessary heft to wield it on the front of a chunky GFX body.
At the nose of the lens is the manual focus ring, which is fly-by-wire without feeling too "floaty". The zoom ring sits, as you'd expect, in the middle of the chassis, telescoping the external zoom mechanism in and out as you turn it, with helpful 45, 60, 80 and 100mm focal lengths (39, 47, 63 and 79mm in full-frame terms) marked on the top.
And of course, the lens also bears Fujifilm's familiar aperture ring for manual control. There is no native way to de-click the ring, however, making it less than ideal for video application.
The Fujifilm GF 45-100mm f/4 is a dream to use. Its smooth, precise zoom facilitates reliable and consistent control in operation, put to the test in one of our shooting scenarios when trying to keep an excitable goose in frame. In similar stead, the autofocus was snappy enough to keep up with our feathered friend, even when he started hissing and moving towards us.
While we didn't empirically measure the equivalent stops of stabilization that it provided, we feel that the claimed five-stop OIS wasn't as robust as the five-stop IBIS in the Fujifilm GFX 100 (though your mileage may vary). Either way, the stabilization is incredibly welcome and makes it much easier to work with the f/4 aperture without having to resort to a tripod.
The stabilization is also brilliant for video – though as noted the GF 45-100mm f/4 misses a trick by not having a de-clickable ring, which would have made it a dream for GFX cinematographers.
We couldn't be happier with the lens' resolving power, in particular its sharpness that's pristine in the center and only mildly less so at the edges. Crucially it's pin-sharp wide open, so there's no need to stop down unless you want to, though the crispness does degrade as you reach the telephoto extreme.
As you'll see from the lab results below, both chromatic aberration and distortion are impeccably controlled; Fujifilm really does know how to engineer good glass. That said, the lab did reveal an across-the-board quirk at f/8 that we believe to be sample variation…
We run a range of lab tests under controlled conditions, using the Imatest Master testing suite. Photos of test charts are taken across the range of apertures and zooms (where available), then analyzed for sharpness, distortion and chromatic aberrations.
We use Imatest SFR (spatial frequency response) charts and analysis software to plot lens resolution at the centre of the image frame, corners and mid-point distances, across the range of aperture settings and, with zoom lenses, at four different focal lengths. The tests also measure distortion and color fringing (chromatic aberration).
As we'd expect for a lens designed to maximise sharpness from high resolution medium format cameras, the GF 45-100mm is extremely sharp in the centre from wide open right through to f/16, although at 80mm and 100mm it's a little less stellar. We also observed an extra dip in sharpness at these focal lengths when shooting at f/8, and consistently so. We expect this may be caused by an anomaly with our particular sample lens.
Corner-frame sharpness isn't as high as it is in the centre, but we'd expect this, and the lens is still very sharp at the edges of frame, whatever the focal length or aperture you're shooting at.
Chromatic aberration is visible as purple fringing on the edge of high-contrast boundaries towards the periphery of an image. It's just about visible in real-world shooting at each end of the lens's focal range, but you'll struggle to spot any fringing when shooting at 60mm and 80mm.
There's very mild barrel distortion at 45mm, but this quickly diminishes, and by 100mm the lens is practically distortion-free – an impressive result.
There is precious little not to love about the Fujifilm GF 45-100mm f/4. An optically excellent performer with versatile focal range, stabilization and weather sealing, all in a package that is (contextually) compact and lightweight – and, perhaps most importantly, affordable.
It's not quite razor sharp at the long end, and the fact that the aperture doesn't de-click is a disappointing for videographers. (We believe the f/8 issue to be an anomaly with our sample, which we certainly hope to clarify soon.) Those minor points aside, though, this really is a superb lens that any GFX owner would do well to pick up.
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