Laowa 20mm F4 Zero-D Shift

General Image Quality

On the following pages we will look in detail at every measurable performance parameter, but for the moment we will consider those subjective elements that can make or break an image.

Field of View

20mm falls between the "wide angle" and "ultra wide angle" ranges. This field of view supplements nicely the range offered by many normal zooms (those typically reach down to 28mm or 24mm). Like the D FA 21mm Limited, its obvious use case is for landscapes and architecture. It can also be quite useful for candids, group pictures in closed spaces, etc.

On APS-C, 20mm is still a wide angle focal length, useful in a variety of situations.

The lens looks bigger than it truly is due to its large hood. The lens body itself is moderately compact, and easy to carry around.

Color and Contrast

Laowa lenses often produce more dramatic contrast than Pentax lenses. Colors remain accurate but there IS a difference with an SMC or HD lens.

This produces punchy results, yet quite pleasing to the eyes. Tonal gradations are well tuned, and transitions from dark to bright areas are gradual.

Metering and Exposure

This is a manual lens; exposure is decided by the user in most cases. However, since there is no aperture coupling between the camera and lens, it is actually possible to operate the camera in P mode ad set the aperture on the lens; it will stop down immediately (not only when half-pressing the shutter). Doing so, we encountered a few cases of underexposure.

Shift Operation

What sets this lens apart is, of course, its ability to be shifted and thus impact the perspective of an image. The effect is best illustrated with the two images below, shot on a tripod.

No shift	Maximum shift

The first image was shot without any shift. The second one shows the same scene, with the lens shifted to its maximum. Note that after shifting, it is necessary to recompose, otherwise the benefits of shifting are lost and the image is simply offset. As shot, the benefits of a shift lens are immediately obvious, with a much more realistic perspective and lines that are straighter.

This second set of images illustrate the same phenomenon with a complex bridge structure. Again, the effect is obvious. It can of course be fine-tuned by using an intermediate shift value.

No shift	Maximum shift

The last set of images, shown below, show the results when the lens is shifted without recomposing. It results in a different composition, but without the benefits of shifting.

Shifted high	No shift	Shifted low

Starbursts

Starbursts are one of the most pleasant surprises we encountered while testing the lens. Despite the 14 curved aperture blades, the Laowa 20mm Shift produces pleasing starbursts at most apertures.

At F4, there is a decrease in contrast and not much to see. F8 (and even F5.6, not shown) already create superb starbursts.

F4
F8

Lens Corrections and EXIF Data

This is a purely manual lens. No data whatsoever is recorded, except for the focal length that is manually entered when powering on the camera.

User Report

A specialized lens such as the Laowa 20mm Shift isn't a run-and-gun type of lens. It is at it best when the photographer takes the time to prepare and set up shots deliberately.

Within the limits of a purely manual lens with numerous knobs and controls, the Laowa 20mm is a pleasure to use. Operating it is straightforward, all controls respond well and do what they should. Despite what we could assume, setting up a shifted capture takes only seconds, even though it involves shifting, possibly rotating the barrel or hood, framing and adjusting exposure. This is a testament to how well the lens is designed.

In the next sections we will look at the optical performances of the Laowa 20mm Shift.