Short Tele, Alternative Legacy: The 85mm f/2 AI-S

When discussing short Nikkor telephotos or classic portrait lenses, a number of lenses come to mind: the 105mm f/2.5 AI-S and the 85mm f/1.4 AI-S. However there was another: the 85mm f/2 AI-S.


^{85mm f/2 AI-S sitting between a 105mm f/2.5 AI-S and 50mm f/1.8 AI-S pancake}

The 85mm f/2 AI-S was classic short telephoto that was introduced in Aug 1981 and had a 14 year run til 1995. It was the AI-S refresh of the 1997 AI lens sharing the same 5 element, 5 group optical formula. It was the slower but more affordable and lightweight (310g and half the weight) sibling to the new 85mm f/1.4 AI-S with both being subsequently superceded by the wonderful 85mm f/1.4D

The fast 85mm was my favourite lens for a long time, and I still gravitate to it for (full frame) portraits - the 85mm f/1.4D in particular produced beautiful out of focus rendering and was bitingly sharp wide open at near/headshot distances. The 85mm f/2 AI-S may not live up to those expectations but lets see how it performs.

Performance

There are varied performance opinions on the internet with Bjorn Rorslett only giving this an underwhelming summary which is different toRoland Vink's thoughts:

Optically this lens is very good. The AI version has the same optics and some reviewers say it has low contrast [..]. I remember being impressed at how sharp it is even wide open, it is probably the first lens I had that I was comfortable shooting at full aperture [..]. The background rendition is not quite as smooth and with straight-edge aperture blades the bokeh is not as quite as rounded as the 105/2.5, but it still a good portrait lens

Wide open the lens can look poor but it seems,on my part to be misfocus AND some minor veiling glare (a little bit like the 50mm f/2 AI) but at f/2.8 it sharpens and at f/4 its very good with much increased contrast. I also find that it performs slightly much worse at MFD as apposed to headshot/portrait distances for 3ft/5ft to mid range. Look at the ruler markings - the rule is at an angle to show plane of focus incase of missed focus.


<sup>centre crop, click for larger

centre crop, click for larger</sup>

At 5ft, you're getting classic headshot/shoulders distances - click for larger, centre crops, focus plane (should be) the seimens star which is on same plane as Nikon logo but also look at the lettering on the batteries.







And tigher

Bokeh

One of the most desired qualities of a short telephoto wide aperture portrait lens is often its out of foucs rendering.





It's not the smoothest out of focus rendering but its ok. It can also give some nervousness in the rendering too.




Flaring is not a great problem here and very useful given you're lightly to aim it at point light sources.

Servicing

Servicing is relativelt simple only slightly complicated by the inner helicoid is part of the lens objective so its a little more fiddly to service but not by much.

• remove rubber focus grip, apply alcohol/acetone to the focus ring retaining ring (and exposes the focus ring screws) and remove.
  
  Loosen the set screw on the front objective retaining collar
  
  
  
  
• you can leave the front optics in place whilst servicing the helicoids otherwise unscrew the retaining collar and subsequently remove the block of 3x front elements
• set the focus at infinity and remove the 3x focus ring screws and lift off focus ring. At this point, if the front optics have not been removed I would reattach the front optics retaining ring - this means when I separate the inner helicoid I can safely set this down
• Mark an infinity alighment mark on the central and rear helicoids
  
  
  
  
• remove the lens mount and aperture ring - no gotchas here, although note the aperture feeler is part of the mount
  
  
  
  
• mark the height of the helicoids key when at infinity.
  
  
  
  As with many short-mid tele AI-S lenses, the helicoid keys are now in pairs underneath the aperture ring. To ensure the keys are reinstalled correctly, I will mark the helicoid key to the left of infinity.
  
  
  
  
  
• remove the helicoid keys and carefully separate the rear helicoid, marking separation aligned with the infinity reference mark
  
• separate the inner helicoid through the front, marking separation aligned with the infinity reference mark.
  
  
  ^{notice I've reattached the front optics retaining ring which makes the inner helicoid easier to manage later (see below}
  
  
  Careful of the lens elements of the inner helicoid that is also the lens objective
  
  
  
  
• Clean the helicoids with lighter fluid, kitchen degreaser, kitchen dish soap and then final clean with IPA. Wipe down/away most of the grease first, perhaps with lighter fluid applied to a thick kitchen tissue
  
  
• Apply a thin layer of NLGI #00 grease to the inner helicoid and remate - ensure this is smooth and light before remating the outer helicoid. On the central helicoid apply a thin layer of the same grease but adjust to taste as this will have the most impact on the lens's focus feel when fully assembled.
  
  Remember to lightly grease the helicoid keys.
  
  
• Once assembled to attaching the focus ring, do not secure the screws but go and calibrate your inifinity focus
  

Optics

This is a 5 element/5 groups design.



If you are simply working on the front elements, you should focus to MFD, loosen the grub screw on the front retaining collar and then twist off the collar.

The front 3x elements are in one housing with the first element secured by a retaining ring that is sealed so apply IPA and leave before freeing with a lens spanner. You may want to lightly scrape away paint to let the IPA work. Once the front element is removed, the rear retaining ring (typically sealed) needs to be removed (also houses the 3rd element) to extract the 2nd element from the rear of housing - I found unseating the rear retaining ring VERY difficult.



The rear element is similar to the front element and sealed and this for me was more difficult to get off - scrape away at the paint and apply IPA and leave for a moment before trying your lens spanner. The rear 2 elements are in one housing that can be unscrewed together although largley unnecessary and can be removed from the rear. The 4th element is underneath a spacer and can be removed onced the rear element is out the way.



Kenneth Olsen has a useful video:

Conclusion

The 85mm f/2 AI-S is by no means a perfect or a true classic lens. There are historically better portrait lenses, and whilst I'm not a massive fan of the 105mm f/2.5 AI-S (my copy was never sharp wide open) I think that lens is clear of this 85mm as is the 180mm f/2.8 ED AI-S. And a look into the 1990s, the 85mm f/1.4D - whilst in a differnt class - is way ahead of both aforementioned.

However, it is very good at f/4 and with care at f/2.8 although I find f/2 is challenging to nail focus every time but it is softer wide open. An original selling point was that it wasn't a f/1.4 or f/1.8 and because of that this 85mm is very compact and its just a little taller than a 28mm f/2.8 AI-S and this design choice still stands today. This lens doesn't necessilarily have a legacy like its faster siblings or longer cousins but it does mean it can be found cheaper and it still standsa as an inexpensive option for those wanting a fast(ish) classic 85mm.