Nikon Lens Reviews

Lens opinions are based on Nikon full-frame (FX) except where noted.  I try to pack lenses I think are best suited for each shooting situation, rather than bringing everything with me, so I try hard to understand my lenses' characteristics through my own testing.

How I evaluate lenses
I use them in the field and also perform a lot of A-B testing, taking lots of pictures and pitting lenses against each other to determine their strengths and weaknesses in relation to each other.  I refer to published Internet sites to help validate my own findings to see where differences, if any, are.  Lens sharpness and other optical properties are some dimensions that can be measured empirically (MTF, CA, etc.) using software.  These findings are relevant when choosing lenses to fit a specific situation but are only part of the decision as testing does not nomally evaluate bokeh, tonality, and other subjective characteristics. 

For the most part, lenses are extremely similar when stopped down.  Just about any lens will do.  The differentiators for me are wide-open performance (sharpness across the frame, fall-off), general sharpness and contrast.  For portraiture, the lens also needs to render skin tones faithfully.  Because I selectively use depth of field, the quality of the defocused areas ("bokeh") is important.

Rather then provide a numerical score to sum up the entirety of lens's properties I'll remain purely subjective and let the reader form his or her own opinion. 

Nikon AF-S 24-70 f/2.8 G ED (own)
The mainstay for all my work on the D3.  There is very little to criticize about this midrange zoom.  The 24-70/2.8 does just about everything perfectly and unobtrusively.  There's some field curvature at the wide end as well as distortion (i.e. horizons aren't perfectly straight) perhaps, but that doesn't bother me.  Already incredibly sharp wide-open with just a tiny bit of fall-off it just gets better from there.  Bokeh is very good given its range.

Bottom line: It deserves legendary status.  It's so good and quirk-free it almost lacks personality.

Nikon AF-S 14-24 f/2.8 G ED (own)
An optical marvel.  Arguably the finest wide zoom ever made by anyone.  In fact, possibly the best wide-angle lens period for a bunch of focal lengths, besting many primes from other manufacturers in the range.  Near perfect wide-open as well, so good already that it doesn't seem to get much better stopping down.  Everything with this lens shows a single-minded focus on optical quality -- those who complain about the missing filter thread are missing the point of this lens, which is to set an optical benchmark.  The more limited zoom range makes it a lens I typically will only put on the camera when I need wide-angle, so I haven't gotten a huge number of images out of it so far, but I've been working with it a lot more recently.

Bottom line: Another one that deserves legendary status, though I don't get to use it as much as I would like to due to its limited range.

Nikon AF 28 f/1.4 D (own)
The 28/1.4 is pricey now that it is only available used, and probably not worth it if you're shooting past f/2.8, when the 24-70 is at least its equal.  It also generates polarized opions between those who love it and those who think it's overrated.  Nikon pulled out all their design stops for to make this no-compromise low light lens and spent 10 years designing it only to sell 7000 or so copies in 10 years on the market.

This lens requires some discipline to get its best because it needs to be precisely focused with such a tiny depth of field at wide apertures.  If you're the slightest bit off, your image will be unsharp, even if shooting using smaller apertures.  When in its element shooting in the dark, it delivers striking images.  It has a low contrast rendering (likely to bring out shadow details hidden in contrasty light) that I was pleasantly surprised to discover works very well on skin for group portraits.  The wide aperture also helps with subject isolation.  Bokeh is generally excellent and smooth, unusual for a wide-angle.  Highlight blur circles do tend to get a little asymmetrical thin crescent shaped edges near wide-open, possibly an aspherical lens characteristic, but stopped down slightly, for a wide-angle, it is nothing short of amazing.  Certainly this does bokeh far better than a lot of lenses.

One aspect of its performance I feel that isn't given much consideration is that it has very little optical aberration like distortion and coma flare which makes it ideal for shooting pinpoint sources of light at night wide open without the characteristic V-shaped ("batwing") smear.  This is not a very big deal for most even though it was probably the feature that drove up the cost of the lens because of the expensive precision ground aspheric element needed to fix this.  But when you know what you're looking for, you'll see it with many other lenses used in this situation, especially the MF 35/1.4.  Compared to the Sigma 30/1.4, its nearest competitor (and DX only), the 28/1.4 appears to have significantly less coma flare.

I tend shoot it at f/2, where it is sharp across the frame and fall-off is essentially not noticeable; also, there's so little depth of field you're forced to shoot stopped down more anyway.  I only shoot at f/1.4 where necessary or when the noticeable fall-off is not bothersome (most available light night situations qualify).  Arguably it's the best 28mm Nikon lens at or below f/2.8 (it's just a hair better than the 24-70 with the unfair advantage of being two stops into its sweet spot) and possibly one of the best fast primes wide open.  The AIS 28/2.8 deserves particular mention when talking about 28mm lenses -- it is also incredibly sharp.  The MF 28/2, the fastest 28mm before the 1.4 version, also appears to have great sharpness, but doesn't hold all the way out to the corners unless stopped down.  To reiterate, the main sharpness advantage to the 28/1.4 is its sharpness across the frame wide-open or near wide-open.  The other 28mm lenses do start catch up when they are stopped down (especially the zoom and the 2.8 prime version).

High ISO capabilities on the newer cameras and great zoom performance have also tempered the requirement for fast primes these days so the 28/1.4 lives in a very, very specialized 2-3 stop zone.  It is happy to be used in regular daylight, delivering a slightly less contrasty image and perhaps a higher tendency to purple fringe on highlights than the 24-70 (tiny compared to the awful fringers like the 85/1.4 or 105VR).  The 17-35 at 28 is a better landscape lens in my opinion with its high level of contrast.

Compared to the 24-70, the 28/1.4 is able to extract a bit more shadow detail, likely due to its inherently lower contrast.  So even though it is a low-light lens, it actually does quite well in harsh lighting conditions such as outdoors on sunny days.  Details in foliage are well-preserved without sacrificing cloud details, for example, and is slightly better than the 24-70 in this regard.  Visual rendition is slightly cooler than the 24-70, in keeping with the warmer trend of recent Nikkors.  The zoom does appear sharper, which is probably due to an actual sharpness difference, but likely more to do with the higher contrast leading to an impression of crispness and sharpness.  Ultimately, the zoom is probably the better choice for general use, unless deliberately packing light and for the aforementioned super low light situations.

Bottom line: Very specialized and very special, it delivers a look like no other lens I have under low light.  It is indispensable if you like to work in its domain between dark and light, but like a fine wine, few will likely need it nor understand what this lens is truly about.  It deserves particular mention and status purely because of the no-holds-barred philosophy behind it, much like Nikon of yore, when they built uncompromising lenses to show the world what they could do, not for a particular market in mind.

Nikon AF 85 f/1.4 D (own)
A great companion to the 28/1.4 when I shoot primes only with the D3.  I acquired it for mainly for portraiture because of its legendary reputation in Nikon circles and it is less intimidating than waving the 70-200VR in front of most people.  I have to express some level of disappointment, possibly due to some overly high expectations caused by the hype around the lens.  Overall image quality, in the way it renders or draws the picture, sharpness, freedom from optical issues, etc., is excellent.  The ability to selectively control depth of field from a wide range of apertures is marvelous.  Bokeh, as expected from something often referred to as the "cream machine" is excellent.  It has old-school solid build quality.  Many people wonder about the little bulge on the lens body near the lens mount, much like a little wart -- it's normal and gives clearance for the AF gear mechanism!

It appears to expose a little hot on highlights in bright conditions compared to the rest of my lenses.  I sense this as due to its tonal curve bringing out a bit more shadow detail, which might point to good low-light performance but might compress the highlights a bit unless compensated for.  This is one of the issues I have with this lens because seems to come close to burning out highlights on fair skin if not taken into account.  The second issue is that I find the lens renders cooler in general, which, in combination with its sharpness seems to bring out the little flaws in people's skin and makes things look a little clinical or sterile, not something that a portrait lens should do.  This characteristic can be toned down in post-processing by warming up the image, so the main penalty really is a bit more processing work but it is a bit of a turn-off.  I also have the suspicion that the rendering may also bring out skin characteristics that, even when toned down, are still there.

It does generate lots of purple fringing on highlight transition areas like chrome grilles on a car in the sun (the 105VR is also quite bad at this), but the remedy is simply to stop down.  One may get the impression that I don't like this lens, but I definitely use and enjoy it a lot as part of my primes-only kit as I find 85mm a great walkaround focal length on FX.  But for portraiture I reach for the 105DC instead.  It's all about understanding lens characteristics and using the right tool for the job.  On FX, the 85 doesn't quite focus closely enough for a decently tight headshot; also when you do get close for a headshot, I feel I'm starting to invading the subject's space as well, possibly putting them at some unease.  Going beyond just headshots, the focal length is decently wide enough for good full-body shots indoors and out.

Bottom line: Excellent all rounder lens, but also a bit of a quandary.  Its coolness and the portrait skin performance, which is a matter of personal taste, prevents me from being totally ecstatic about the lens (however see my comment on the 105DC).  But I still rate it extremely highly regardless and use it a lot.

Nikon AF DC-Nikkor 105 f/2 D (defocus control)  (own)
I was intrigued with the possibilities of this lens and debated at length over whether or not I needed another 105mm prime, having the 105 VR macro aready.  So far I have been extremely pleased with it and it is much nicer for portraiture than the 85/1.4 from how it renders skin, but also because it can render a tighter headshot than the 85 due to a higher overall magnification.  The skin rendition is warmer than the 85, but not as warm as the current batch of Nikons, which may have swung almost too far to the warm/yellow side.

The lens's big feature is the Defocus Control (DC) mechanism that is supposed to allow you to fine tune the quality (generally interpreted as smoothness) of the defocused areas ("bokeh").  However, this effect is not well documented by Nikon and is misunderstood by many.  The DC effect does actually work to fine-tune the defocused areas and most importantly their transition from sharp to out of focus, but I don't use it as much as I could.  The out-of-the-box rendition works just fine for me without potentially forgettable tweaks that could come back to haunt me if I forget to set the control back to zero.  The Defocus Control, when used to fine tune the bokeh in one direction (say behind the subject) does have the reverse effect in the other direction.  Given its raison d'etre as a portrait lens, bokeh and transitions from focus to defocus are excellent.

This lens is very sharp stopped down slightly, is already sharp wide-open with a little veiling softness (not too bad if you like a little ethereal glow to your subject).  Sharpness is not the defining property of the lens here, but skin rendering is.  Compared to the 85/1.4, the 105DC gives sharp, detailed skin tones, but somehow doesn't get as clinical as the 85/1.4 and definitely exposes more neutrally and faithful to the original shooting conditions.  I'm actually surprised how contrasty the lens is, given its portrait nature, but I believe this is a deliberate characteristic -- the midtones where skin resides are handled subtly, yet shadow details aren't exaggerated, giving the lens an appealing combination of subtlety and punch at the same time.  If I were to split hairs, then the 85/1.4 might be the choice for low light portrait or figure work (B&W and/or a little harder lighting) or with darker-skinned models, while the 105DC would be for more conventional portraits or with lighter-skinned models.  The 105DC also lets one move in closer than the 85/1.4, which is an important consideration for headshots.  Bokeh is easily as good as the 85/1.4's; the 105DC can render out of focused areas as well as, or better than the 85/1.4 despite its one stop disadvantage because of its longer focal length.

When DC is used, the 105DC delivers better bokeh than the 85/1.4; when it is turned off, the lenses are too close to call.  When the DC ring is set to be equal the aperture set, I find it introduces a slight bit of veiling softness like when it is shot wide open, so I try to set the DC ring one notch lower than the set aperture to ensure softness.  There's occasional misconception about using the DC ring and not being able to autofocus -- that's untrue -- AF works perfectly fine with the DC function.  The key is to always focus after you manipulate the DC ring as the plane of focus will be changed.

For regular work, the 105DC does fine duty as a regular telephoto though for most uses, the 70-200VR is my main sports / theatre lens because of zoom flexibility.  It focuses quickly with its large aperture and internal focus construction and delivers great images.  It is definitely capable of delivering sharp images and ranks as one of my sharper lenses.  The only visual issue I have with it is purely due to its IF construction which causes some longitudinal chromatic aberration on high contrast (black to white) edges shown as a greenish fringe just behind the point of focus and magenta in just front of the point of focus.  This is usually only noticeable at really high magnifications and is not an issue for portraiture since faces don't tend to have huge swings in contrast.  I have noticed that all other IF lenses show this to a degree and the 105DC does seem to have good control over this, being a bit better than the 85/1.4 and the 105VR in this regard.

Bottom line: Absolutely unbeatable for portrait work and a great telephoto as well.  This lens is like a fine wine -- subtle and sublime.

Nikon AF-S VR Micro-Nikkor 105 f/2.8 G (own)
The 105VR was the first dedicated macro lens I purchased in all my years of photography.  I also bought it to serve a low light medium telephoto role as well before the 70-200VR.  The macro feature coupled with VR is very useful for what I term "informal macro" -- you see something neat on your walk and you take a macro shot of it.  Normally you might have to get out a tripod to get the steadiness needed to run the small apertures required for sufficient depth of field, but the VR helps a lot.  As a regular lens, it is very sharp across the frame, especially on DX, good colour and saturation (warmish rendition like other recent Nikkors), and has a surprisingly good rendering for skin for portraiture (better than the 85/1.4 in my opinion).  Combined with the macro capability it makes a really good baby portrait lens as few other lenses can focus in as closely.  Compared to the 105DC, the VR seems to capture a bit more shadow detail on otherwise equivalent exposures.

The main drawback of this lens, to me, is its propensity to generate purple fringing on contrasty highlight areas wide open, which requires some stopping down to get rid of, as well as a small bit of lateral chromatic aberration which is handled nicely by the more recent Nikon bodies.   I have recently noted a tendency for this lens to make people's heads look as if they were 10lbs heavier (OK, well, that's probably an exaggeration).  I don't know why or if I'm seeing things and the lens doesn't have much linear distortion that I can tell but there may be other optical things at work like the IF design shortening the actual focal length.  As a result, I'm avoiding using this on adults; I suppose babies would be fine.  It's a shame if this was the case as otherwise it would be a true jack-of-all trades lens.  Note that this tendency is only noticeable when compared to the 105DC so in actual practice this may be a non-issue. 

Autofocus can be a little jumpy at times, where the lens has to hunt around a little to focus, but understandable given the range of distances it has to deal with.  The limit switch is definitely a good idea to use, and it's too bad there's no setting on it to limit to just the macro range.  I don't see AF as an issue for most uses of this lens, including sports.  It'll focus fast enough especially with the limiter.  Autofocus is handy in the macro range as well -- If I'm lazy and not using some kind of camera/lens support, I'll typically try to place the area I want in focus in one of the AF areas and use continuous focus while I rock back and forth to frame the image and wait for the right moment.

Bottom line: A very well-rounded lens.  It does everything well and VR coupled with macro is a great idea. 

Nikon AF-S VR 70-200 f/2.8 G (own)
A pretty mandatory jack-of-all-trades purchase for the professional shooter.  I avoided buying one for as long as I could, hoping it could be supplemented by other primes.  But I eventually succumbed as I started to do more sports.  This lens is near flawless on DX, but has some definitely noticeable corner light fall-off wide-open on FX that is fixable by stopping down or post-processing; in addition, I am usually shooting stopped down slightly to gain depth of field anyway, so fall-off isn't an issue for me typically.  However, it does have softness issues on FX at the long end which again isn't a large problem for me but could easily be for others, especially landscape shooters who need sharpness across the frame.  On DX, I can hardly tell it apart from the 105VR at the same aperture -- that's how good it is. 

The 70-200 excels in image quality, VR, bokeh, pretty much everything, and for many (myself included) it is a must-have for the flexibility it offers.  It'll do sports like hockey, field sports, theatre work, weddings, portraits, anything you name (except macro, which you can still do with a close-up filter) brilliantly.  The VR, while not quite in the same performance class as the VR II in the 105VR, is much, much better than no VR.

In terms of handling people pictures, it does extremely well.  It has nice bokeh and provides much-appreciated flexibility out in the field.  Skin rendering seems to be quite decent, probably better than the 85/1.4, if punchier in colour and slightly on the warm side.  Extreme backlighting situations may be a bit more challenging due to extra flare compared to primes, but it's by no means something that can't be worked around.  While the lens is challenged in focusing in closely, headshots are certainly possible when zoomed to the longer focal lengths (incurring the associated telephoto compression effects).

Bottom line: The latest in a line of legendary performers.  A no-brainer for DX shooters.  FX shooters need to decide if the corner softness and fall-off issues are acceptable, but it otherwise delivers incredible results. The reality is that this is the only lens in its range so the choices are limited.

Nikon AF-S 17-35 f/2.8 D (own)
Very much obsoleted by the 14-24.  This lens provides very good performance when stopped down, indeed surprisingly close to the 14-24.  Centre performance is excellent starting from wide-open.  With all the hype over the 14-24, this lens is actually closer in performance than one might be led to believe.  However its Achilles heel is its wide-open corner performance especially at the wider end where it is quite mushy and soft on FX.  In fact, even on DX it's easily bettered by the consumer zooms at the wider apertures until about f/5.6-8, after which its superior microcontrast really pops.  My particular copy also is very contrasty which works well for landscapes -- it has an ability to render blue sky and cloud detail extremely well.  On the flipside, I find the images a little muddy on the shadow details.  Its only real advantage over the 14-24 is its ability to take filters, and a wider focal length range that lends itself to being a lens you can leave on the camera otherwise it is surpassed in all other respects.

Bottom line: Brilliant not so long ago, but technology changes and it's hard to recommend now except for stopped-down landscape use.  I might also use it like I did back in the film days -- 17-35 plus fast 50mm plus 70-200 as a photojournalist's kit.

Nikon AF-S 17-55 f/2.8 G DX (used extensively)
The only Nikon DX midrange pro zoom.  This lens provides generally good results and is probably a better overall choice on DX than the 17-35.  Optically, it has similar rendering characteristics to the 17-35 (not always a good thing) but has better sharpness wide-open.  It may have fractionally more chromatic aberration which is no longer an issue with the latest Nikon bodies.  This would be my midrange choice for DX but would be careful with group shots of people as there can be some interesting facial distortion effects towards the outside of the frame.  The bokeh is of the donut kind and can be somewhat unpleasant and distracting under certain conditions.

Bottom line: Not legendary, but a very solid, competent performer that delivers.

Nikon AF Micro-Nikkor 70-180 f/4.5-5.6 D (own)
Billed as the first zoom macro lens, this is a very handy lens for a nature hiking kit, possibly with the 17-35.  Say you're walking around and see a nice mountain view, then a particularly interesting flower or insect, and the next moment a deer -- this lens can do it all.  Because it is relatively slow, issues like fall-off don't appear on the FX frame and it's certainly better than the 70-200VR in the corners at the long end.  This lens is certainly not a speed demon in focusing as the front of the lens racks in and out (thankfully there is a focus limit switch); nor is it fast in aperture, but it does fine in good illumination.  Image quality is very good and there are no issues I can pick at.  In general, it doesn't appear to be quite as sharp as the 105VR, but the latter is a very, very sharp prime lens so you wouldn't expect a zoom to come close.  In reality, the zoom flexibility means I use it more than the 105VR.  It does only go to 1:1.3 macro reproduction ratio, but with an additional 6T lens can go to 1:1 if that's essential.  It has a very welcome built-in tripod foot that might be a little short but is useful in any case.  One thing to note with this lens is that you cannot (or shouldn't) use autofocus with it when using Nikon's macro ringlight (R1), but serious shooters will likely be using manual focus when having an elaborate flash system anyway.

I use this lens for traveling because it's more compact than the 70-200VR and gives me macro capability.

Bottom line: A nature hiker's dream lens.  Discontinued, and getting pricey as a result.

Nikon AF-I 300 f/2.8 D ED (own)
Your typical supertele in that it is optically excellent.  Sharp wide-open and doesn't improve much further from there.  The AF-I motor is noisier than the near-silent AF-S, but is not too bad at all and focusing speed seems just fine as it slams into focus and you feel the lens torquing over.  The AF-I mechanism is also a little unusual in that the camera meter has to be activated before the manual focus override works.  This is a heavy lens, but actually more compact than the successive AF-S and VR designs.  It also has one more ED element than the others which has led to speculation that this is the sharpest of them all before the designs were reworked to accommodate the AF-S ring motor mechanism (the same speculation exists for the other AF-I lenses).  Coupled with the TC-14E, this lens still delivers great images at 420mm and f/4 without visibly losing quality.  You can get by without VR, but you'll need good lens technique on this lens.  Transitional bokeh can be a little nervous, but far bokeh as would be expected on a supertele, is great.  I suspect the new VR version probably addresses some of the bokeh concerns from the favourable reports , but I haven't used one.

Bottom line: A good bargain if you don't want to fork over for a new one.  There are concerns over support and service for a 10+ year old lens, especially if the motor quits, so keep that in mind.  I figure the worst case is that I'll be left with an extremely good manual focus 300/2.8 that still has value.  Also, the coreless motors are arguably the same sort of technology used for inside the camera body for focusing, film advance, and shutter charging and those tend not to fail.  So who really knows?

Nikon AF 50 f/1.8 (non-D) (own)
The classic nifty fifty, my first Nikon lens.  Cheap as grass, this lens is as sharp as they come when stopped down into its optimum range.  It definitely does not have the most attactive bokeh, which can border on horrible at times, but what can one expect for the price?  The only way around that is to be mindful of backgrounds when shooting with it.  With the advent of the D3 and 24-70 as well as my 28/1.4 and 85/1.4 prime kit, I hardly find any use for this lens.  Perhaps if an AF-S 50/1.4 came out it might be worth considering.  However, the 50/1.8 is cheap enough for most people to drop a few bucks on without breaking the bank just to see what the fuss about primes and low light photography is about.

Bottom line: For the price, everybody should buy one to experience no-flash photography.  A great one for baby pictures.

Nikon AF-S VR 18-200 f/3.5-5.6G DX  (own)
THE jack of all trades lens.  This one packs all of Nikon's knowhow into a superzoom that works surprisingly well.  If you use it in its optimal range, you can get high quality images.   It does just about everything as well as you need it to except for maybe close-focusing capability.  The VR works very well and makes the lens usable in many indoor situations where it would have been be unusable otherwise due to its relative slowness.

Stopped down, one can even do outdoor, nicely lit sports like soccer well.  My only gripe with it is a bit of a loss of contrast that causes highlights, especially noticeable in cloud detail, to blow easier.  This might be solved by adding a slight level of underexposure to the camera, possibly up to 2/3 stop.  It is certainly heavier and longer than the other consumer zooms so it isn't necessarily for the person who is used to an 18-55 plus D40 form factor.

Bottom line: Ultimate travel lens, possibly the only lens one might need so it's not a bad starter lens to figure out what other lenses you'd need to buy.  There are compromises to the optical quality that some may find noticeable or even objectionable so IQ seekers might want to spring for the 16-85 instead.

Nikon AF-S VR 16-85 f/3.5-5.6G DX (briefly tested)
A compact, versatile lens.  If the 18-200 sacrificed some image quality to get its huge zoom range, this one tones down the zoom range and speed (f/5.6 at 85mm!) in order to get excellent image quality that comes close to pro zooms.  The slow speed on the long end does visibly show as a darkened viewfinder.  I was very impressed with this lens with the short amount of time I had with it. 

Bottom line: My current choice of a DX travel lens that delivers a decent range of focal lengths, but more importantly, excellent image quality.

Nikon AF-S 24-85 f/3.5-4.5G (used extensively)
This is a compact, versatile full-frame lens with a useful range for travel pictures.  Construction is similar to the current crop of DX zooms like the 18-70: lightweight, plasticky, and with a barrel that alarmingly has a lot of play.  Focusing is full-time silent wave so focus can be manually tweaked any time.  Optically, this lens delivers very good image quality and is capable of great results.  Sharpness and contrast wide-open are especially good for a consumer-level zoom.  The downside is a fair bit of barrel distortion at the wide end that changes into pincushion distortion at the long end.  At 24mm wide open there is also very noticeable light fall off in the very corners.  The lens is also quite varifocal, meaning that it changes focus while zooming, another consequence of its price.  The distortion and fall-off can be corrected in software, so it may not be an issue, more an inconvenience.  The front element comes right up to the front of the lens, and I found it reassuring to have the lens hood installed to protect the front element from accidentally hitting something.

Bottom line: A good choice for travel use with FX if you aren't bothered with its limitations.  The 24-85/105/135mm area is one that Nikon needs to address with a decent full-frame quality VR zoom that would be great for travel.  Perhaps a revised 24-120VR might foot the bill.

Nikon SB-900
If you're used to the form factor of the SB-800, the SB-900 is definitely an SB-800 on steroids.  Luckily my camera bag will accommodate it, but it's sufficiently larger in all dimensions to cause problems with those who have created the right setup in their bags for the older SB pro units, especially since it's taller by about a half-inch.

The SB-900 solves just about all the usability issues I've had with the SB-800 (well done, Nikon!).  It provides a welcome ability to rotate the flash head 360 degrees finally.  You get a power switch that can select the remote and master CLS modes directly (flip the switch instead of having to hold down the SEL switch, SEL again, cursor up, SEL again, hold down SEL switch).  These two features alone are worth the price of admission.

Other notable improvements: there is a new gel holder works nicely without having to lower down the diffuser grid or tape stuff to the flash.  This is handy as you can now really concentrate light when using CLS.  The user interface has changed, with a spin dial instead of a d-pad, which lets you go to settings faster, and context-sensitive hot keys.

Unfortunately, there are issues that fly against the "why fix it if it ain't broke" philosophy.  The base of the flash is now wider (not the metal hotshoe base, but the narrower part directly above it).  This wider piece could cause problems fitting older non-Nikon gear such as cold hotshoe adapters.  Some of these accessories are now being introduced with the SB-900 in mind, or you can probably modify them by filing off the extra material, but it's a bit annoying.  The plastic support foot for the flash does not have a metal threaded insert for the tripod stud, like the SB-800 does, so I worry about wearing out the plastic threads now.

Others to come: 

Nikon AF-S 18-70 f/3.5-4.5 G DX (own)

Nikon AF 16/2.8 fisheye (own)

Nikon AF 28-105/3.5-4.5 D (own)

Nikon SB-800 (own)

Hensel Porty Premium AS RC (own)

Markins M-20 Head (own)