Laowa 4.5-10mm F/2.8 Fisheye Zoom Lens Review

DISCLAIMER That Venus Optics provided a prototype lens for the purpose of this review. The build and optics appear completely finished but our unit was not equipped with a parfocal zoom mechanism. Final lenses shipped to customers are expected to be parfocal. All opinions in this review are our own and Venus Optics had not influence its content.

Construction & Ergonomics

Venus Optics has been constantly improving its manufacturing process which shows on the Laowa 4.5-10mm F/2.8 Fisheye Zoom. This model appears well built with tight tolerances. The lens barrel and rings around it are made of metal with a smooth matte finish that is commonly seen among higher-end lenses. The mount itself is made of stainless steel.

This relatively compact manual zoom lens has the three rings required to control it. These rings cover most of the lens barrel, leaving less than 1cm fixed on both ends. The front-most ring is the focus-ring. This is the widest of the three. Half of it has ribs to provide grip, while the other is smooth with focus markings in meters and feet. It has a 90° throw to go from 10cm to infinity. It takes a good amount of precision to focus perfecting given the available range-of-motion.

Right in the middle of the lens barrel, one finds the zoom ring. It also has a 90° throw to zoom from 4.5 to 10mm. This focal-range is not completely comparable to one for a rectilinear lens. Most photographers will use one end or the other. On an APS-C sensor, having the focal-length set to 5½mm or less produces a completely circular image that covers 180° in all directions. When mounted on a Micro Four-Thirds camera, it has to be zoomed out completely to 4.5mm.

Zooming in expands the circle which clips its top and bottom. Only at 10mm does the image cover an entire APS-C sensor. Of course, for a Micro Four-Thirds camera, this will happen around 9mm. An image captured at 10mm will cover a 180° field-of-view when measured diagonally. Any focal-length in between is neither circular not rectangular.

The last ring, closest to the body is the Aperture-Ring. There are markings in full-stops from F/2.8 to F/22. The ring rotates with a 35° throw which places apertures really close together. There are moderate detents at each full stop which help select the corresponding aperture. Adjusting the iris to a specific fractional aperture-ring is virtually impossible.

Considering its extreme field of view, this lens, like all those that capture a circular image, cannot accept filers or a lens hood. Venus Optics designed a special cap to protect its bulbous front lens element. The cap is made of metal with same smooth finish as the lens itself. The lens measures just shy of 7cm in diameter and 6cm in length. While not a heavy lens, at 338g, it feels dense for its size.

Using the Laowa 4.5-10mm F/2.8 is relatively straight forward. It takes some practice to set focus precisely at short distances due to the throw of the focus ring. One also has to be careful when selecting the aperture. Since its value is not reported to the camera, photographers must rely on the markings and detents, but those only exist for full-stops. Other than that, every ring rotates smoothly and silently. For IBIS to fully work with this lens, users must select the focal-length on camera. This unfortunately means adjusting it every time the user zooms.

Optics

Evaluating the optical quality of a fisheye lens is challenging. Sharpness is measurable, as covered in-depth further down this review. Distortion is expected. Peripheral illumination poses an interesting challenge since it is physically impossible to build a flat plane that covers a 180° angle-of-view. So, instead of the usual procedure, we measured the difference in brightness at corners between consecutive aperture values. The experiment shows that there is less than 1/8 stop difference in brightness at F/2.8 vs F/4. For all other apertures, brightness is completely consistent with the F/4 measurement.

The contrast rendered by this lens is good. While certainly not as crisp as the Laowa 17mm F/4 Zero-D Shift review here, it is much harder to make a fisheye impervious to all flare. It is quite good though at minimizing flare from light sources appearing in the frame. While the outer edge of images capture as circular images shows pronounced blue fringing, it occurs minimally along edges of high-contrast within the frame.

The Laowa 4.5-10mm F/2.8 Fisheye Zoom can focus down to 10cm from the focal-plane, beware of field-curvature common to fisheye lenses. Field curvature occurs when a lens focuses on a section of the spheroid rather than a plane. From F/2.8 to F/4, a perfectly flat subject captured close to the lens cannot be entirely in focus. By stopping down to F/5.6, depth-of-field becomes sufficiently deep to compensate for this.

Sharpness

This fisheye zoom lens manages to capture fine details well. The center of the frame is reasonably sharp at F/2.8 and becomes very sharp from F/4 to F/11. Stopping down further introduces softness due to the unavoidable diffraction limit. The exact point when diffraction appears actually depends on the camera resolution. With a 26 megapixels APS-C image, diffraction becomes apparent starting at F/13.

Ideally, lens sharpness is completely analyzed using a controlled workbench. Unfortunately, the extreme field-of-view captured by most fisheye lenses makes it impossible to measure edge sharpness this way. Instead, edge sharpness was estimated from dozens of real-world images. The good news is that there seems to be a minimal drop of sharpness towards the extreme edges or captured circle of photographs from this lens.

Select a focal-length and aperture combination to see a 100% unmodified crop taken from the center of the image in either Circular Fisheye (5mm) or Rectangular (10mm) mode. The lens was mounted on a Sony Alpha A7R IV in APS-C crop mode which is equivalent to a 26 MP APS-C sensor. For this reason 5mm instead of 4.5mm could be used for the circular image.

Inspecting the crops above shows that this lens is consistent in sharpness from F/4 to F/11. There is a very minor reduction of details at F/2.8. Then, at F/11 and beyond diffraction imposes a limit on details. There is sufficient resolution to print images at typical sizes, up to about 12" x 9", depending on the camera. For online presentation, the sharpness of the Laowa 4.5-10mm F/2.8 Fisheye Zoom is completely sufficient.

The main challenge to getting sharp images comes down to the ability to focus. When subject distance exceeds a few meters, camera Manual-Focus Assist tools such as Electronic Magnification and Focus Peeking really help. At those distances, the depth-of-field is sufficiently extensive that a subject will remain sharp even if focus was not perfectly set. On older Mirrorless Digital Cameras, the EVF sometimes struggles in low-light which causes the view to become soft. Once that happens, it is virtually impossible to nail focus.

Focusing on a subject less than one meter away requires a lot of precision and patience. It was not practical to capture images up close without a tripod, when using this lens. The focus ring must be adjusted very carefully and any movement of the camera threaten to throw the subject out-of-focus. A recent camera could help a lot with this!