Nikkor Z DX 50-250mm F/4.5-6.3 VR Review

The second DX lens for Z-mount is the Nikkor Z DX 50-250mm F/4.5-6.3 VR
Nikkor Z DX 50-250mm F/4.5-6.3 VR telephoto lens. Not only is it the longest Z-mount lens around, the APS-C 1.5X Focal-Length-Multiplier makes it equivalent to a 75-375mm lens on a Full-Frame. This covers the range normally used for portraits, street photography and distant detail shots. It sports a F/4.5 maximum aperture at wide-angle which is typical for a variable aperture telephoto zoom and closes down to a very dim F/6.3 towards its long end.

This long zoom lens captures a 31° angle-of-view at its widest and just 6.3° at its longest, starting exactly where the DX 16-50 F/3.5-5.6 VR leaves. Like the other DX lens, the DX 50-250mm F/4.5-6.3 VR sports an optical image-stabilization mechanism which is absolutely essential for such long and dim lens. The Vibration Reduction system of this lens claims 5 stops of efficiency over hand-holding.

The Nikkor DX 50-250mm F/4.5-6.3 VR can focus down to 50cm from the focal-plane at wide-angle and 1m at telephoto. This gives it a good maximum magnification of 0.23X. While this cannot handle macro photography, it can be very effective at cropping out distracting elements or just focusing on specific details. A quite internal focusing system allows this lens to record video without distracting sound.

Body Design

While this lens is not that small, it packs quite a reach for its size. This is the first telephoto zoom to feature a collapsible design, allowing it to measure 12cm in length when closed down. It extends 4cm longer to start at its 50mm minimum focal-length and stretches to almost 20cm at its maximum 250mm focal-length. While the zoom is external, its focusing mechanism is completely internal.

At the front of the Nikkor DX 50-250mm F/4.5-6.3 VR, there is a standard 62mm filter-thread. The inner barrel does not rotate while changing focal-length or focus-distance, making it possible to use a polarizing filter. This lens also has a bayonet mount for an optional lens hood.

The cylindrical body of the DX 50-250mm F/4.5-6.3 features two interlocking inner barrels that extend when the lens is zoomed in. A whole 7cm of the main barrel is actually an enormous zoom ring. It has a stiff fine rubber texture to provide grip. The zoom ring has a 90° throw from 50 to 250mm. Close to the mount, there is a slim customizable control-ring. By default, it acts as Quick-Shift in AF and performs MF. It can also control aperture, which could be useful given that there is only a single control-dial on the Z50, Exposure-Compensation or ISO. This control-ring rotates smoothly and without stops.

Everything outside from the lens mount to the hood mount is made of plastic. The DX 50-250mm F/4.5-6.3 VR appears to be better built than the DX 16-50mm F/3.5-5.6 VR. The inner lens barrels fit more tightly together and show very little flex between them. Inside the lens, there is a simple 7-blade mechanical aperture.

Nikkor 50-250mm F/4.5-6.3

Optical Performance

Long lenses are easier to design than wide-angle ones, yet making one this compact requires compromises. Near its wide-end, center sharpness of the DX 50-250mm F/4.5-6.3 is pretty sharp. There is some very slight softness from wide-open at F/4.5 all the way until diffraction starts at F/9.5. Corners however are extremely soft and blurry. Although stopping down makes them less blurry, details always look fuzzy in corners.

Around the middle of the zoom range, central sharpness is actually very good at any aperture.Corners though start out somewhat soft and improve to an almost usable level at F/6.7. Things gets soft again stopping further down, so there is no point where an image becomes consistently sharp from edge-to-edge.

Telephoto performance is very similar. At the maximum F/6.3 aperture, there is a little softness in the center, yet it becomes sharp from F/6.7 to F/9.5, just before diffraction takes over. Corners at telephoto have defintely softness until F/8 but them improve until about F/13. Again, there is not any aperture where sharpness is even, although F/8 is not too far off.

Below are 5 crops taken from a photograph, repeatedly captured for each combination of focal-length and aperture. Smaller pieces are cropped from extreme corners of the image, while the middle wide crop is taken from the center of the image. Select an aperture in a row for a desired focal-length to see the crops from the corresponding image. When judging image quality, keep in mind that these crops come from a 20 MP image which is normally used for up to 18x12" prints.

Upper Left

Upper Right

Center

Lower Left

Lower Right

One good outcome from this lens is that it does not exhibit any optical distortion. It preserves straight lines remarkably well. There is a small amount of vignetting throughout the zoom but it is easily corrected. The lens appears to be quite resistent to chromatic aberrations too, although it was not tested under extreme conditions due to overcast weather.

The builtin autofocus motor of this lens is extremely quiet and can move swiftly, assuming that there is plenty of ambient light. This can become rather slow when shooting towards the long end of the zoom in low-light where the maximum aperture is so dim that the autofocus sensors have little to work with.

Conclusion

The overall verdict is that the Nikkor DX 50-250mm F/4.5-6.3 VR is somewhat better than the DX 16-50mm F/3.5-5.6 VR yet falls short of expectations. This lens gives quite a lot in terms of optical performance to acheive its compact size and light weight. This may be what some people are ready compromise though, particularly those who are looking more for souvenirs than prints. There are no lenses to compete with this one yet but using an adapter to mount an AF-S lens could give better results.