Fujifilm X100 Optics

Fixed focal-length lens
Very good performance from the 35mm equivalent fixed lens.

The Fuji X100 has a fixed, 23mm f/2 wide-angle lens with an equivalent focal length of 35mm because of the X100's ~1.5x crop factor. Sharpness and contrast were very good across the frame, with very low levels of coma distortion, negligible chromatic aberration and just a touch of softness in the corners at f/8. A hint of flare is detectable around very bright objects close to the edges of the frame, but it's really quite low at f/8. Very good results here.

Macro
The Fuji X100 captured a larger-than-average minium area, with slightly soft detail. The flash throttled down well, but was partially blocked at minium distance.

The X100 captured a somewhat larger-than-average minimum area measuring measuring 3.24x 2.15 inches (82 x 55 millimeters) at its closest focus distance. Details were slightly soft in the center, though corners weren't much softer. (Most lenses have some softening in the corners at macro distances, so the X100's lens did better than average here.) The Fuji X100's flash throttled down fairly well producing a good exposure, but the flash is partially blocked at closest distance, causing a dark shadow in the bottom-left of the frame. The other corners show moderate shading.

Geometric Distortion
Low to moderate distortion from the Fuji X100's fixed, wide-angle lens.

The Fuji X100's 35mm equivalent lens produced just under 0.3 percent distortion which is lower than average, especially for a wide-angle lens. Vertical pincushion along the sides is moderate, though, at about 0.6% percent. Its complex nature (barrel in the center and pincushion near the edges for horizontal edges, pincushion for vertical edges) makes it more difficult to correct in software without profiling, though it's low enough that it probably requires no correction for all but the most critical applications. The camera does not appear to be applying geometric distortion correction to its JPEGs, as RAW files contain identical amounts. This is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide-angle) or inward (like a pincushion -- usually at telephoto). A very good performance here.

Chromatic Aberration and Corner Softness
Low chromatic aberration in JPEGs, though higher in uncorrected RAW files. Minor blurring in corners when wide-open.

Chromatic Aberration. Chromatic aberration in the corners of JPEGs is very low and dull, and hardly noticeable. In the center, it was practically nonexistent. (This distortion is visible as a slight colored fringe around the objects at the edges of the field of view on the resolution target.)

Corner Softness. The Fuji X100's lens produced some blurring in the corners wide-open at f/2.0, though it was fairly minor but it did extend pretty far into the frame. Flare as well as the camera's C.A. removal caused high-contrast edges to be less defined in the corners, while corner shading reduced overall contrast, contributing to the appearance of softness. The center of the image however was quite sharp and contrasty. At f/5.6, corners are only slightly softer than the center, which was very sharp. Very good performance here. As mentioned above, a small amount of corner shading ("Vignetting") is visible in JPEGs wide-open, as indicated by the dimmer corner crop. (More on corner shading below.)

Chromatic Aberration Correction. We weren't surprised to discover the Fuji X100 reduces chromatic aberration during JPEG processing (good for JPEG shooters), as quite a few cameras do these days. Above are crops from in-camera JPEGs (left) as well as uncorrected RAW files converted with Adobe Camera Raw. Chromatic aberration is brighter and more obvious in uncorrected RAW files, being exacerbated by the slightly soft corners at f/2.0, though it's still fairly well controlled at only 5-6 pixels in width worst-case. At f/5.6, the number of colored pixels drops to 3-4, and there is practically no C.A. in the center at either aperture.

Corner Shading
The Fuji X100 corrects for some corner shading in its JPEGs.

The Fuji X100's RAW files also show more corner shading than in-camera JPEGs, so the X100 is correcting for some of the corner shading. Rollover the JPEG and RAW links above to see the effect of the corner shading correction, at both f/2.0 and f/5.6. (RAW files have no correction.)

For in-camera JPEGs (left), we measured just over 1/2 EV of corner shading at f/2, which fell to about 1/4 EV at f/4 and below. Uncorrected RAW files showed more corner shading, at just over 3/4 EV wide-open, falling to about 1/2 EV at f/4 and below. Still, fairly good performance here.

Accuracy
Excellent accuracy from the electronic viewfinder and LCD monitor, though the hybrid optical viewfinder isn't very accurate.

The Fuji X100's electronic viewfinder and LCD proved very accurate, both showing about 100% coverage. The hybrid optical viewfinder's framing guides showed very poor coverage at only about 88%, as well as a substantial offset in both the horizontal and vertical directions. However, when the shutter button is half-pressed and the camera focuses, the framing lines shift in response to subject distance. Alignment improved dramatically and coverage improved to about 93% with the shutter button half-pressed. That's still below average compared to SLR optical viewfinders which typically offer 95% coverage or better, but seems pretty good for a rangefinder camera (we haven't tested any other rangefinder cameras recently, so we can't really compare.)