The Sony Sonnar FE 55mm F/1.8 ZA is the second prime lens for use with Sony’s new full frame ‘E’ system, (formerly called NEX that used only APS-C sized sensors). It’s a relatively small and light-weight lens and is a good match for the diminutive A7 series cameras. Oddly, it has a highly concave (appears sucked in) front element, and convex (rounded like a marble) rear element; I only mention this as it is out of the ordinary, and not something a user needs to be concerned with; see MTF chart and x-ray view in the product shots.
Fit and finish are very good. The lens appears to be made up of a mixture of metal and plastic. There is a ribbed grip around the focus ring. Sony claims the use of three double sided aspherical elements in the design. Sony says this lens is dust and moisture resistant. Zeiss T* coatings. Lens is made in Thailand.
Filter size is 49mm, and is quite popular for ‘E’ primes. Be careful when mounting filters as the filter threads are plastic. Also, the way the lens is designed it is hard to mount filters with big fingers, the filter threads are part of an inner circle, inside the lens barrel, see product shot front. I’ve had great luck with Tiffen and Hoya; they’re priced appropriately, and are the only brands I use now.
Focusing. This lens auto-focuses quickly and mostly accurately, and has a very quiet linear focusing motor so it can be used for video. The front filter ring doesn’t turn when focusing, so your polarizers and grads will work great. The focusing ring is easy to turn, and is damped about right. Amount of focus ring travel depends on how fast you turn the ring. If you turn it real fast, it will go from close-up to infinity in about a 1/4 turn, but turning it slow can take well over a complete turn.
Box and contents
Front element and filter ring
Sony MTF and X-ray view
Specifications
| Official lens name and code | Sony Sonnar FE 55mm F/1.8 ZA T* SEL55F18Z |
| Box contents | Front cap, rear cap, petal type hood, vinyl carrying case and user’s manual. |
| Cost | $999 as of 6/14. |
| Build Quality | very good. |
| Additional information | This model is made for Sony ‘E’ mount cameras, and won’t work on ‘A’ mount cameras as of this review. |
| Optical configuration | 7 elements in 5 groups. |
| Angle of view | 43° diagonally, (29˚ when mounted on an APS-C sensor camera). |
| Aperture | 9 blades, curved |
| Coverage for | Sony FE 24x36mm sensor. When mounted to an APS-C camera, the focal length is equivalent to 82.5°. |
| Depth of field and focus scales | nothing. |
| Minimum focus, image plane to subject | About 19.5″ (500mm). |
| Minimum focus, end of lens barrel to subject | About 16.25″ (413mm) from front of lens barrel, no hood. |
| Infinity focus hard stop | No. |
| Length changes when focusing | No. |
| Focus ring turn in AF | No. |
| Filter size | 49mm. |
| Filter ring rotates | No. |
| Maximum reproduction ratio | 1:7.1 or 0.14x. |
| Minimum F/stop | F/22 |
| Sony Teleconverter compatible | No. |
| Length changes when zooming | N/A |
| Dimensions WxL | 2.53″ x 2.81″ 64.5mm x 70.5mm. |
| Maximum extended length | Lens does not extend. |
| Weight | 9.9oz, (281g) bare. |
Optical qualities summary.
| Lens flare/ghosting | overall, good control. |
| Light fall-off | Low to moderate wide open, almost nothing at small apertures. |
| Color fringing | excellent control of lateral type. I do see a small amount of magenta axial type from wide open to F/4, mostly correctable in Lightroom 5+. |
| Bokeh | somewhat smooth stopped down a bit, harsh along the sides at wide apertures. |
| Color | seems about the same as other Sony lenses. |
| Close-up filter | works good, +4 tested; get as close as 160mm instead of 413mm. |
| Coma | Low at F/1.8, almost gone at F/2.8, totally gone at F/4. |
| Regular filters | cause no noticeable additional light fall-off. |
| Filter size | 49mm. A popular size for Sony ‘E’ primes. |
| Distortion | Very mild barrel type. |
Miscellaneous samples.
The first image is the usual stamp shot from the old site, cropped and displayed at 100% The subject is a standard US stamp, 0.87″x 1.0″ or 22mm x 25mm. It’s very sharp, but the maximum reproduction ratio is small at 0.14x. The second is a full resized image of distortion. The next four show how the lens performs at F/1.8; warning, depth of field is slim, the whole frame is not in focus. The last three images show how the lens handles the full sun. Sun stars are very weak.
F/5.6
Mild barrel distortion
F/1.8, ISO 100, 1/1600s.
F/1.8, ISO 100, 1/2500s.
F/1.8, ISO 100, 1/2500s.
F/1.8, ISO 100, 1/8000s.
F/8
F/8
Vignetting gallery below.
Vignetting or light fall-off is not strong at any aperture, although it’s noticeable near or at wide open. Regular filters cause no additional problems, and you may be able to stack two without getting dark corners. There is very little change in light fall-off patterns between close and infinity focus.
F/1.8
F/2
F/2.8
F/4
F/5.6
Resolution samples
Below are the full size samples. They show a wide range of details, scattered evenly across the frame so it’s easy to tell how the aperture affects sharpness in the centers, mid sections, sides and corners. All were taken in RAW and converted to jpegs, no sharpening or other enhancements have been made, and they have not been cropped. Feel free to download them and flip between the images to see the changes. Disregard the trees and bushes along the bottom of the images as they are not quite in the depth of field at wide apertures.
I see a very sharp center wide open, with the mid-sections and sides a little soft, but totally usable at F/1.8! Max resolution across the frame at F/5.6! Diffraction causes noticeable softness at F22. 
Full size (7630 pixels wide) image link buttons below. Best viewed on a desktop computer. Laptop and tablet users may have to manually expand image.
F/1.8 F/2 F/2.8 F/4 F/5.6 F/8 F/11 F/16 F/22
Background highlight blur (bokeh) at short focusing distances.
Here are a few full size images of a subject taken from a relatively short distance. You can get a good idea of the character of out of focus highlights. I did not take these on a tripod, so they are not perfectly lined up. Bokeh looks neutral, meaning the disk is even at most apertures, but along the sides at wide apertures the disk turns to a triangular shape, with a harsh outline; that’s typical of a fast lens.
Full size (7630 pixels wide) image link buttons below. Best viewed on a desktop computer. Laptop and tablet users may have to manually expand image.
The Sony FE 55/1.8 ZA turned in a great review. It’s nice to see another stellar prime lens for this system. Positives include low color fringing along the sides, excellent coma control, very sharp centers at all apertures, great across the frame sharpness at F/5.6-8, very low light fall-off, and good bokeh. No real negatives to report, however, I don’t like that it’s missing OSS or optical stabilization, well, that’ll be for the second version right? Also, the 55mm focal length is not of my liking; it’s a little too long for ‘normal’ use; I’d prefer 45mm, but oh well, maybe it’s just me on that one. Anyhow, two thumbs up on this one. I think it’s worth the price, especially if you shoot in low light, or want some background blur.
That’s it for this review. Please check out the Sony FE 55/1.8 ZA lens at B&H Photo and help support the site!