Sony NEX-6 Optics

Zoom
Wider than most zoom kit lenses, with decent far-field performance.

The Sony NEX-6 is available bundled with a 16-50mm f/3.5-5.6 OSS "kit" lens. This optically stabilized lens possesses a fairly typical optical zoom ratio of about 3.1x with a 35mm equivalent focal range of about 24-75mm. That's significantly wider than most kit lenses without losing much reach at the telephoto end. (A more common focal length for an APS-C camera kit zoom lens is 18-55mm.)

Sharpness and contrast at full wide angle (16mm) are decent at f/8 over most of the frame, and chromatic aberration isn't an issue since the camera suppresses it (see below), however some flare is visible around the building's white surfaces. It's difficult to judge corner performance here because of the depth in this scene, so we'll do that below. Performance at 32mm is also not bad at f/8, just slightly soft. At full telephoto (50mm), the lens performs fairly well, better than many kit lenses we've seen.

Overall, a very useful focal length range with decent far-field optical performance at f/8 for a kit lens, and the built-in optical image stabilization will come in handy for low light and tele shots. See sections below for comments on macro, geometric distortion, corner softness, performance wide open, chromatic aberration, etc.

Digital Zoom
The NEX-6 offers three types of digital zoom. Sony's new "Clear Image" digital zoom is available at 2x magnification, standard digital zoom up to 4x, and Smart Zoom is available where the camera crops away the unused portion of the image when a lower resolution is selected. You can combine the various digital zooms as well, but maximum total digital zoom is 4x at full resolution, increasing to 8x at the small image size (~4 megapixels).

Clear Image Zoom does a decent job at 2x magnification, though there's still a noticeable loss of fine detail and some visible aliasing artifacts, despite Sony's claim of being "nearly equivalent" to optical zoom. 2x Clear Image Zoom combined with 2x standard digital zoom shows fewer aliasing artifacts than just 4x standard digital zoom, but results are also a bit softer. It's difficult to tell given the lack of fine detail in this scene at these zoom levels, but it's probably best to avoid using digital zoom altogether and instead crop, upsize and sharpen as required during post processing.

Macro
Slightly larger than average minimum coverage area, with good detail. Flash throttled down well.

As with zoom performance, the Sony NEX-6's macro performance will depend entirely on the lens mounted. However with the E-mount 16-50mm kit lens set to 50mm, the NEX-6 captures a minimum area measuring 3.65 x 2.43 inches (93 x 62 millimeters), which is slightly larger than average for a kit lens. Detail is good in the center at f/8, just a touch soft, though corners and edges of the frame are softer. (Most lenses have some softening in the corners at macro distances.) Some corner shading is also noticeable. The flash did a very good job throttling down at minium distance, resulting in a good exposure. The flash also had no trouble clearing the lens as there is no detectable shadow.

Geometric Distortion
Lower than average geometric distortion at wide angle and telephoto, but the NEX-6 always applies distortion correction when the 16-50mm is mounted.

With the 16-50mm kit lens, the NEX-6 produces JPEGs with about 0.4 percent complex barrel distortion at wide angle, which is lower than average and hardly noticeable. At the telephoto end, there's only about one pixel's worth of wavy distortion. 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).

See below for uncorrected distortion from this lens.

Chromatic Aberration, Corner Sharpness & Vignetting
Low levels of C.A. (the camera suppresses it). The lens produces some pretty soft corners.

Chromatic Aberration. Chromatic aberration in the corners with the NEX-6's 16-50mm kit lens at wide angle (16mm) is low with just minor magenta fringing, and the center of the image shows very little C.A. The camera does a pretty good job at suppressing much of the lateral C.A. produced by the lens (see below). At full telephoto (50mm), C.A. is also low with blue fringing that's quite muted.

Corner Softness. Wide open at full wide angle, the 16-50mm lens that came with our NEX-6 is soft in all four corners, with the lower-right and top-left corners being the softest. Softness extends pretty far into the frame as well, though the center has good sharpness and contrast. At full telephoto corner sharpness is better but still quite soft, though the center isn't quite as sharp as wide angle, with lower contrast.

Vignetting. Moderate vignetting (corner shading) is noticeable at full wide angle, as indicated by the darker corner crops, even with automatic vignetting correction enabled (see below). Vignetting is milder at full telephoto, but still noticeable.

"Stopped-down" to f/8, corner sharpness at wide angle is actually worse than wide open at f/3.5 in our lab shot. That's a curious result, so we retook these shots but got the same results. We suspect focus shifted between between the two apertures, keeping the center sharp with the extra depth-of-field provided by stopping down while focusing less optimally for the corners. We'll look into this further when we do a full suite of tests on this lens for SLRgear.com. At full telephoto, corner sharpness is markedly improved at f/8 versus wide open at f/5.6, and performance in the center is also improved. Although improved compared to wide open, vignetting is still visible at f/8, particularly at wide angle.

Lens Corrections

When shooting in JPEG mode, the Sony NEX-6 includes the ability to automatically correct for geometric distortion, chromatic aberration, and lens shading (vignetting), as images are captured. Only E-mount lenses are supported, and raw files are not corrected.

Geometric Distortion

Above, you can see the uncorrected geometric distortion from the 16-50mm kit lens is very high at wide angle, with about 3.3% barrel distortion. Very high barrel distortion at wide angle is common for Micro Four Thirds lenses, but this is the first time we've seen it this high from a Sony E-mount lens, and the amount of correction required explains some of the corner softness we see at wide angle. At the telephoto end, pincushion is relatively low at 0.2%, but still higher than the corrected JPEG image.

The default Distortion Correction setting is normally Off for the NEX-6, but is forced to Auto when the 16-50mm lens is mounted, so we used dcraw to convert the raw file without corrections applied. Thus, it appears that Sony is taking a page from the Micro Four Thirds' playbook by allowing higher geometric distortion in this lens to make it more compact, and correcting it in firmware.

Chromatic Aberration

Above, you can see significantly higher lateral Chromatic Aberration at wide angle with Chromatic Aberration Correction disabled, though the difference at telephoto is minimal because C.A. is low at telephoto to begin with. The default for this setting is Auto.

Lens Shading

Mouse-over the links above to see the difference Lens Shading correction makes at wide angle when wide open at f/3.5 (the worst-case scenario for most lenses). As you can see, corners are brightened without affecting brightness at the center, though some fall-off is still left behind in the corrected image. The default setting is also Auto.

Coverage
Excellent accuracy from the EVF and LCD monitor.

The Sony NEX-6's OLED electronic viewfinder and LCD monitor both showed essentially 100% coverage with our Sigma 70mm f/2.8 prime lens. This is excellent performance, though not a surprise given its image is derived from the main imaging sensor.