Wider please, but on a budget: the Nikon AF-P 10-20mm f4.5-5.6 DX VR review

Most of you know me for being at the bleeding edge of hardware and being able to deploy the difference – that was true at least until my back injury last year, which has severely limited what I’m able to carry for any length of time. It has forced me to look at things I would normally have ignored; for whatever reason, in this industry light and small is usually also synonymous for ‘entry level’ and ‘cheap’. But in doing so, I’ve found some surprising hidden gems: hardware that most people pass over at face value for lack of bragging rights or seemingly ‘obvious’ deficiencies. Be prepared to be surprised, I was. This will be the first in a series of el cheapo reviews.

When I started off with DSLRs, the king of Nikon wides – DX only at the time, of course – was the AF-S 12-24/4. It was a decent performer even on the 12MP bodies, but started to fall apart with anything much more resolving than that. Distortion was…spectacular and not easily correctable. It was also very much a prosumer build lens, with light plastic everything, the slower AF-S motor and a non-prosumer whopping $1200 price tag or thereabouts. Fast forward fifteen years and we now have a successor (there was also the AF-S 10-24mm f3.5-4.5 DX, which sits somewhere between the two in price, build and optics). It takes many things away: it isn’t as long (20mm vs 24mm); it has an even plastickier build – even the mount is plastic – and it’s pretty much a stop slower across most of the range. BUT: it is $280 or so, new, from your choice of online outlet, and has VR, the new fast AF-P pulse motor, and weighs just 230g. It even covers FX from 13mm upwards, though the Z6 and Z7 will auto-crop to DX and you can’t override this. If you are not a fan of long reviews, then just enjoy the images, skim through the rest, and click the buy link at the bottom of the post.

To put things in context: this lens cost the same as my camera (an albeit unusually cheap D3500 kit) but less than a medium format battery. It continues to amaze me how far optical design is being pushed at both ends of the spectrum: we have some truly amazing premium lenses, but by relaxing one or two of the usual design constraints (maximum aperture, distortion, secondary corrections, use of moulded plastic asphericals etc.) we also have some truly amazing budget lenses.

I suspect the rationale goes like this: the company has already bought or developed all of that expensive optical computation software; the price-volume curve at this end of the market is wildly nonlinear, and something like the 10-20 is probably going to sell two or three orders of magnitude more lenses than say the superteles or PC-Es, and be more profitable as a total project. More resources than you might expect get thrown into it, and suddenly – you actually have a really good lens.

Don’t get me wrong: Nikon has clearly cut corners here. The mount is plastic; there are no switches for AF/MF or VR on/off (that has to be done in a menu, and some cameras require a firmware update). The AF-P motor is only compatible with the most recent generation or two of cameras. There is of course no rear gasket. Hell, it’s so cheap that the regulatory labels and MADE IN THAILAND are part of the injection moulding of the shell – they aren’t even a separate sticker. Speaking of which, the nameplate – metal on even Nikon’s midrange lenses – is a sticker here. Even the mount indexing dot isn’t the usual glued-in plastic ball: it’s printed.

Like the rest of the DX AF-P lenses, it’s a class leading study in both marketing stinginess and engineering brilliance: despite all of the compromises, the lens feels neither hollow, nor insubstantial nor flimsy. The zoom ring rotates with constant friction and good smoothness, and none of the usual plastic-on-plastic stickiness; it doesn’t feel very different to my gold ring Nikkors, to be honest. And the focus ring is fly by wire, but silky smooth and very nicely calibrated.

Where Nikon hasn’t cut too many corners is in the stuff that really matters: optics and mechanics. The 10-20 uses a surprisingly complex 14 elements in 11 groups, with three asphericals and (surprisingly) no ED elements. There are however a lot of achromatic doublets used in the design: three or four, depending on how you’re counting. Undoubtedly this keeps unwanted dispersion to a minimum. There is very little longitudinal chromatic aberration but some lateral visible at wider focal lengths; the small aperture probably helps too. (It also means that peak resolution is found somewhere between maximum aperture and f8, after which diffraction starts to soften things a bit on the 24MP DX bodies.)

The optical tradeoff made appears to be in field flatness and distortion. There’s some strange focal plane curvature going on towards the corners that’s more visible at close distances and seems to go away a bit at infinity. This manifests as softer corners, but actual behaviour seems to be more like strong rearward field curvature. It’s even clearer when you put the lens on a FX body: there’s a really abrupt dropoff in the corners of the image circle beyond DX. So although you can use it from 13mm upwards on FX, you probably won’t want to because the corners take a beating. In fact, the image circle around 17mm or so is actually larger than at 20mm. However: if you have a D850 and don’t mind using the 1.2x crop, it’s actually pretty good: you have a very cheap wideangle that will cover ~15mm-equivalent upwards, and still keeping better-than-DX-resolution (about 30MP or so).

The actual characteristics of distortion are also worth some discussion: it’s mostly simple, of the barrel-type, at every focal length. There is almost none of the messy moustache-type (uncorrectable). It also avoids the typical wide angle projection* distortion: the edges don’t get stretched excessively larger compared to the middle, so the images appear surprisingly natural in perspective for a lens this wide. (I would still of course recommend holding the camera level.) This appears to have been one of the main design tradeoffs: distortion against field curvature and sharpness. It also isn’t entirely symmetric on my copy, which suggests some sensitivity to sample variation; I didn’t have a second copy to test.

*Wide angle foreground-background emphasis is NOT the same as projection: projection is when you flatten 3D space into 2D, e.g. for maps of the earth. Frequent stitchers will know there are a lot of different ways of doing this and the results can be very different: but what is stitching other than creating an effective angle of view wider than the one you’ve got on the camera?

Flare is very well controlled, with only one or two purple ghosts at the wider focal lengths. Coma is similarly well controlled, with some smearing visible in the corners on the 24MP DX bodies, but nowhere near as bad as you’d expect. If you’re wondering why I haven’t talked about sharpness/resolution and bokeh – it’s because there’s nothing much to report. Central sharpness is as good as you can wish at pretty much all focal lengths from wide open, but falls off into the corners due to the previously mentioned field curvature. As with all recent Nikon lenses – macrocontrast is high, with microcontrast probably best described as coarse. It isn’t as refined as the Z lenses or gold rings, but it also doesn’t have the same coatings or price tag. Finally, don’t even bother talking about shallow DOF: remember this is a slow superwide.

I’m going to conclude by stating the obvious: Nikon has made an impressive lens, made truly impressive by the price and size. The tradeoffs are sensible and can easily be worked around. For the DX shooter, it’s a no-brainer: buy one. For the FX shooter who only needs the occasional wide: it’s also a no-brainer at the price: buy one. For the serious wide shooter, you probably already have your poison of choice – but if you want to go light and still have the wide option – you guessed it, buy one (and a D3500). And yes, falling into the second camp, I’ll be picking up one of my own. MT

The Nikon AF-P 10-20mm f4.5-5.6 DX VR is available here from B&H.

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Ultraprints from this series are available on request here

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