Sigma ART lens?  135mm f1.8  Just came out.  
I  haven't seen one in the wild yet.  
The images I've seen so far have been very good.

https://www.adorama.com/sg13518nk.html

the Sigma ART is a great lens, but there's nothing wrong with a 105mm f/2.8

If you want a super creamy, smooth background, the 85 f/1.4G sets the standard.   I had the 85 f/1.4D version, and performance wise, it was about the same.   But, I found it was a little too long on a cropped sensor camera for a "normal" size room.  About all you could get was a tight headshot.  So I sold it.  I kind of regret that since I now use a full frame camera.

I recently bought the 85 f/1.8G, but I haven't used it at all so I can't comment on the performance.  It does appear to be very sharp. The bokeh seems good, too, but maybe ever so slightly less impressive than the f/1.4G version.  Not much less, and the average person probably wouldn't notice.  But photography nuts might.   Don't have a single picture to share, since I deleted all of the test shots I took, and they were all boring anyway (don't have any resident models around here). The sample images I've seen all look great, though.  


A couple of reviews:

85 f/1.4G

85 f/1.8G

I'm partial to my 105 DC ...take the time and do focus calibration though

I have been thinking about a 135mm DC ( lots of samples on nikoncafe ) but was waiting to borrow a Sigma 135 Art to compare

My  go to is actually 70-200 ..love what this lens does for portraits . Far more versatile than the DC lenses ( much faster focus )

Easy to find the 105 and 135 DC lenses used in mint shape .  I don't think I would pay new full price for it

People buy the DC lens then sell it  because they  don't like the DC feature or the chromatic aberration ( when shooting F2 and playing with DC )

ITs a love hate thing !

https://fstoppers.com/review/best-portrait-lens-youve-never-heard-nikon-135mm-f2-3099

I do almost all of my portrait/headshot work with the 70-200 2.8. I've though of picking up a 85 1.4, but it's reportedly only marginally better that the 85 1.8, so I'll probably get one of those first. The only reason I would get the 85 is really for closer focusing than the 70-200 can do, but.

The 105 is also an amazing lens for portrait work, but the 70-200 covers the range and if your shooting at f4 or 5.6, it's really hard to tell the difference... really hard.

All things considered, I'll take the versatility of the 70-200 any day, but if someone gave me a 85 1.4, I wouldn't throw it back. It really opens up what you can do with a super shallow DOF and creamy bokeh.

Get the 70-200. You'll have way more fun in the long run and have one of the best (if not the best) tele zooms ever made. You'll have a lens that spends 80% of it s time on your camera, not 99% of it's time in your bag. Sharp, lightning fast focusing (almost scary how fast it focuses on my D750). Plus if you put it on the d500 your get the crop factor working for you too.

Run, don't walk, to get a 70-200. Now.

ETA:

70-200 on a d4











85 1.4 on a d3






And I have no 105 on my flickr... sorry.

It will make your 400 feel like a bus compared to a GTR.

I think that the 200 f/2 and the 105 1.4E surpass that lens (in that order).

I think the verdict is still out on the new Sigma 135 1.8.

A comparison of the three is available here
http://www.fredmiranda.com/forum/topic/1484875

The 70-200 2.8 VR2 (I can't speak to the E) definitely focuses quickly but doesn't make my 600 f4g feel like a bus compared to a GTR.

The focus speed for the 105 1.4E is definitely noticeable (slow).

Even though I already own the 70-200 VR2 I bought the 105 1.4E and am very happy with the purchase.

That wouldn't surprise me.  My 300 f/2.8 VR was better than my 85 f/1.4, too.  

I was thinking about something in the 85mm range, though.

I read through this and looking at the comparison shots it looks like the Sigma 135 1.8 is a fine lens at a very attractive price point.

I cast my vote for the 70-200 f2.8 VRII.

I agree with the 70-200. It is the workhorse lens for me on FF and portraits. I can immediately change perspectives without having to swap primes, IS pretty much guarantees no shake blur, and it is sharp (speaking from Canon, but Nikon will be just the same). I had the Canon 85 f/1.2L II, but I never used it anywhere close to the 70-200. Even when I did use the 85, I was stopping it down anyway, so I was pretty much negating the large aperture.

I have both a 85 & 135mm Zeiss. They will flat knock your socks off. Manual focus only, if that's an issue.

Primes seem to do better for potriats, IMO.

My .o2