The Nikon 20/1.8G puts in a decent performance mostly in line with the other members of Nikon’s line-up of f1.8 primes. That it’s the most expensive of the group hints at the challenges that the designers face with ultra-wide lenses. It is unique in being the only lens from Nikon that is wider than 24mm and offers an aperture of f1.8.
Comparing the Nikon 20/1.8G to other lenses is not easy now that the equivalent Sigma lens is on the phase-out. That leaves only wide-angle zooms to compare it with. But zooms and fixed-focals are made for different purposes, the zoom being more flexible in producing the angle-of-view that you need and the fixed-focal offering a larger aperture for better dof-isolation and shorter shutter speeds. And normally you’d expect a better image-quality from a fixed-focal.
So let’s go through some of the alternatives and see how they compare.
Compared to Nikon AF-S 14-24/2.8G ED
The legendary 14-24mm brings you down to an incredible 14mm focal length that is 30% shorter than the 20/1.8G and gives you an angle of view of up to 114 degrees. On the long end it gives you 20% more magnification. It offers a constant f2.8 aperture over its zoom range and a professional build-quality. But be prepared to invest around 1600 EUR (incl. VAT).
The 14-24/2.8G is a unique lens that no other manufacturer offers. Its performance is top notch for any wide-angle zoom and it has astonishingly low distortions. Comparing image-quality at f2.8 shows that this zoom can almost keep up with the 20/1.8G. But it does not allow for filters, suffers from flares and ghosts pretty easily, and is larger and heavier then the 20/1.8G. This lens earned a Highly Recommended rating in my review. But if your budget is limited or you need filters or the larger f1.8 aperture with its potential for shorter exposure and better background blur, the new 20/1.8G is the lens of choice.
See my Nikon 14-24mm f2.8 review for more details.
Compared to Nikon AF-S 16-35/4.0G ED VR
The Nikon 16-35/4.0G VR has a lot going for it: the zoom range is very practical for a wide-angle zoom. At 16mm, it starts 20% wider than the 20/1.8G and goes up to 35mm which reaches well into the domain of a short “normal” lens. The constant f/4.0 aperture and an image stabilization that is good for two stops longer shutter-speeds makes it a proposition that would be pretty attractive had it not been for the somewhat disappointing performance especially considering the price.
This zoom costs 10-20% more than the 20/1.8G plus is larger and heavier than the fixed focal. Still, valued on its own it is a worthy compact wide-angle-zoom for those who start into FX-land or want to keep their options open for a future upgrade to an FX-body. If you need flexibility in the angle of view and mostly shoot stopped down to maximize dof this lens is for you as the stabilization is a definitive advantage if shoot at f8 and need to hand-hold the shot. If you want better image quality and need background-blur even on your wide-angle shots the 20/1.8G is the better choice.
See my Nikon 16-35mm f4.0 review for more details where this lens earned a Recommended rating.
Compared to Nikon AF-S 18-35/3.5-4.5G ED
The 18-35mm zoom is an affordable alternative to reach into wide-angle photography on a full-frame body. But at a little over 600 EUR (including 19% VAT) you get no constant maximum aperture, no stabilization, it goes only down to 18mm at wide end, and has no gold ring. Does this look like a bad deal?
Well, no! I’ve tested this lens and it performs astonishingly well which earns it a clear Recommendation. Its zoom range starts 10% shorter than the 20/1.8G and covers all your needs up to 35mm which makes it pretty versatile. The 18-35 also has the advantage of being substantially lighter and smaller than both other zooms – and did I mention the lower price? So again your decision should be based on what you really need on the wide-angle side: flexibility to cover many situations in a 2x zoom range or better background-blur and bokeh plus better capabilities to shoot under low-light conditions.
See my Nikon 18-35mm review for more details.
Nikon AF-S 20mm f1.8G ED final verdict
The new Nikon AF-S 20mm f/1.8G ED is occupying a pretty unique position: It’s the only lens with a focal length shorter than 24 mm that covers a full-frame sensor and offers an aperture brighter than f2.8. The only competitor out there is the Sigma 20/1.8 which is a very old design without focus motor, poor performance at the borders and corners, and limited availability: Sigma Germany does not even list it on their web-site any more. So I really would advise against getting the old Sigma instead.
But a recommendation is only earned if a lens delivers. And it does, although you need to know its limits to get the best results: For closer distances it’s sharp wide open in the center with an acceptable degradation of sharpness towards the corners. It can deliver some nice background-blur for an ultra-wide lens. And once you stop down to f4 or beyond it also delivers good results for capturing landscapes and architecture even on a 36 MP full-frame sensor. It is small, light, and has a reliable autofocus plus weather sealing. Thus it earns a Recommended.
But think about what you really need for your venture into ultra wide-angle land. If it’s really bokeh and background-blur you’re after shooting at 20mm or you need the shortest possible shutter times than the 800+ EUR will get you the best tool to achieve that. But if you normally shoot landscape or architecture with the need to sharply reproduce fine details over the entire frame and/or a larger depth of field you’ll be probably shooting more at apertures between f5.6 and f11. Then you might consider one of the zooms listed above as an alternative which also give you the flexibility to adapt the angle-of-view to fit your needs.
Good to very good performance at closer distances even wide open.
Quiet and reliable AF operation.
Weather sealing at the lens-mount.
Green outlining/haloing in the background when shooting wide open.
Needs stopping down to f5.6 to achieve critical sharpness across the full frame.