The Nikon AFS 85/1.8 G (released at the start of this year) is a slightly odd product. Unusually for Nikon, the new version doesn’t cost a lot more ($50, give or take a bit) than the old one; doubly unusually, it isn’t a warmed-over cosmetically-modified version, either. (It’s also now made in China, which might have something to do with it. The old lens was made first in Japan, and then Thailand since 2010.) The 85/1.8 D was a simple double Gauss design with 6 elements in 6 groups; the new one uses a 9/9 optical formula. The elements in front of the iris ostensibly retain the double Gauss formula, but everything afterwards is new. As far as I can tell, the same basic optical principles apply, except every single element in the rear group has been replaced with an achromatic doublet of sorts; not a true achromatic doublet because there’s an air gap between neighbouring elements.
Images from Nikon USA. The D is on the left, the G is on the right. Note far more complex rear group; the pairs of lenses do effectively the same thing as the single lenses in the earlier design. The images are to scale, too – note increase in size. It doesn’t seem to be any heavier, though – and noticeably lighter than the 85/1.4 G.
This complex formula has two benefits: firstly, lower chromatic aberration because there’s that extra element there for correction; secondly, internal focusing is now possible (the previous design focused by moving the entire optical assembly back and forth, like all double-Gauss designs). As far as I can tell, the front and rear elements (possibly more than one) are fixed, and the rest move back and forth. At this point, it’s worth noting that unlike Nikon’s newer optical designs, it’s remarkably free of any exotic technology – whilst the bottom of most lenses now play host to entire essays in abbreviations about Nikon’s lensmaking prowess, the 85/1.8G is remarkably clean. All it has is internal focusing and the silent wave motor – that’s it. There’s no Nano-crystal coating, no ED glass (let alone Super ED glass) and no aspherical elements. Even the new 50/1.8 G employs asphericals!
Regular readers of my site will know that I was originally a huge fan of the 85/1.4 G, especially on the D700 for it’s sharpness, quality of bokeh and incredible ability to shoot into direct light sources with minimal to no flare. You’ll also know that despite trying multiple samples, I was never quite happy with the performance of this lens on the D800E; mainly due to lateral chromatic aberration wide open, and so-so edge performance. It’s therefore logical to assume that there are optical quality reasons as to why I’m now using the 85/1.8 G instead. You’d be right.
In all of my A-B testing with similar subjects, several samples of both lenses – the 85/1.8 G was consistently sharper in the center at f1.8, let alone f1.4. it’s possible that real resolution was identical, however, the 85/1.4 G showed so much lateral chromatic aberration that it robbed the images of perceptual acuity. It was also sharper at the edges – markedly so, especially on the D800E. It’s worth remembering that at f1.8, the 85/1.8 G is wide open, and the 85/1.4 G is 2/3rds of a stop down. Granted, it’s easier to design a good slower lens than a faster one, but then again, the 85/1.4 G has a huge amount of technology in it – ED elements and Nano-crystal coating, for starters. Interestingly, the optical formulae for both lenses are nearly identical.
Bottom line: the 85/1.8 G is sharp at every aperture, across the frame, even on the D800E – providing you nail the focus, of course. There is remarkably little falloff in sharpness from center to edge; consistency and microcontrast improve marginally to f4, but it’s already outstanding by f2.8. I only shoot this lens wide open, which should give you some indication of how I feel about the optics. Chromatic aberration under normal situations is almost non-existent; a remarkable performance. Even though this lens has 7 blades instead of the 9 of its predecessor (and 85/1.4 G), bokeh remains pleasing, neutral and smooth. I’ve yet to see any odd artefacts like double imaging or nervousness, but there is a tiny bit of spherochromatism (color fringing) in the out of focus areas. In fact, it’s one of the better-rendering lenses I’ve used in this regard. Color transmission is neutral, per the current crop of Nikon lenses; though the saturation is unsurprisingly not as high as the Nano-crystal equipped optics.
You’re probably wondering what the tradeoff is, given the huge gulf in price between the 85/1.4 G and 85/1.8 G; the last line should have given you a clue. It has to do with contrast, saturation, transmission and flare. It seems that the Nano-crystal coating makes an enormous difference to all four; the 85/1.8 G takes a noticeable hit in every area compared to the 85/1.4 G (it still improves on the old lens in every way, however). The problem stems from flare; when you have extraneous light bouncing around inside the lens between elements – a good coating minimizes reverse reflections off air-glass surfaces – everything else suffers. The most obvious manifestation of this is under backlit conditions, of course – especially when there is a bright point light source in the frame. The 85/1.4 G shows almost zero flare; the 85/1.8 G gives an enormously spectacular trail of reflections off what appears to be every single element. This can be pleasingly cinematic for atmosphere or video work, except the lens has no hard infinity stop, which makes focus pulling challenging. For stage/ performance work, it’s a pain in the ass. Unfortunately, the supplied hood makes no difference simply because it can’t block light from entering the front of the lens – and it’s these rays that are causing the problem.
Internal flare also lowers contrast; macrocontrast especially. Microcontrast is a bit worse, but not by much. By f2.8 both lenses are neck and neck here. The knock on effect is a reduction in overall saturation; no surprises here. Perhaps the least obvious, and most surprising side effect is a huge reduction in transmission (read my article on the difference between T stops and f stops for more detail). At any of the wide apertures, the 85/1.8 G transmits between 1/2 and 2/3 stop less light than the 85/1.4 G; this is to say that if both are set to a physical aperture f2, then you’ll find the 85/1.8 G’s required shutter speed for a given exposure to be noticeably lower than the 85/1.4 G. In other words, if you set 1/100s f2 ISO 200 on both lenses, the 85/1.8 G photo will be underexposed by 1/2-2/3 stop. The reason is because a lot of the light entering the lens isn’t making it to the sensor plane, thanks to suboptimal coatings.
That said, it’s still better than the old lens.
The new lens gains a silent wave motor and loses an aperture ring; it’s still plastic, but now the crinkle-finish variety to match the modern bodies and lenses. The plastic type appears a lot less brittle than the 85/1.8 G, though admittedly I’ve never had issues with any of the older lenses other than a propensity to pick up scratches easily. The silent wave motor isn’t any faster than the screwdriver method; it’s about the same, actually – especially on a body with a high voltage built in motor like the D3 or D4. The difference is in precision: it’s a lot easier to move a coreless linear motor in the small increments required to adjust for small changes in focusing distance than a geartrain with associated backlash. In practical terms, you’ll find the new lens a lot more precise than the old one. (It still remains useless if you use an older camera that requires an aperture ring.) The lens also gains environmental gaskets, making it a good choice for pairing with a similarly sealed body.
I thought that it would be easy to write a conclusion to this review; it isn’t quite so straightforward. I’m going to turn it around a bit instead:
Buy the AFS 85/1.8 D if:
- You shoot with a manual focus camera, or want to use the lens both on your Nikons and other systems via an adaptor – otherwise you’ll have no aperture control.
- This lens is optically inferior to both of the G versions, and not much cheaper than the AFS 85/1.8 G.
Buy the AFS 85/1.8 G if:
- Resolution at maximum aperture and CA are important, i.e. you shoot with a D800/ D800E.
- You want lower contrast because you shoot with an older, lower dynamic range body
- Size and weight are important; the lens is noticeably lighter and a bit smaller than the 85/1.4 G.
- Price is important
- You like cinematic flare.
Buy the AFS 85/1.4 G if:
- You need as much light gathering ability as possible, or shoot frequently under very low light conditions
- You shoot into bright point sources a lot
- You shoot with a lower resolution body
- Notice I haven’t mentioned bokeh yet: the 85/1.4 G is slightly better than the 85/1.8 G, but it doesn’t justify the increase in cost.
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