Hands-on with the Nikon Nikkor Z 70-200mm F2.8 S

its right, of course. Then that equipment work 10 or 30 years... Even more.

The 2.8 zooms are not much more expensive than what the F were and , actually, the 70-200 starting price is lower than what the F was ... nothing has changed to be honest. Well, we do have now sigma and Tamron huge alternative at less thought,

Don’t forget that for many F to Z switchers they are not buying a system from zero. They will likely sell what would otherwise be duplicated so that the proceeds from the F heavily subsided the purchase of the Z’s. So it’s not necessarily a $10,000 outlay. That, and they do it in stages as they can afford to.

There's also some element (no pun intended) of choice on Nikon's part here - Canon just released a vastly more compact F2.8 70-200mm with the only caveat being the lack of internal zooming. I think this is sadly just another way Nikon is falling a little bit behind...

@JokingJ: I look at things the exact opposite way. It's sad to see Canon falling behing little by little in terms of image quality. It was just unthinkable a few years ago to have a Canon 70-200mm f2.8 not be the best zoom on the market. We have grown accustomed to Nikon taking the lead on image quality. And this lead is increasing generation after generation.

The 70-200 is a staple portrait lens. Many photographers need f2.8 for DoF control.

I don’t understand those who keep mentioning f4. It’s like you’re not aware of the target market of this kind of professional lens.

@Einride: agreed, but I would still argue that the degree of subject isolation you get at 200mm with f4 is still more than shallow enough for most applications.

@4sofnature they don't like it if you don't worship it, probably paid PR control. but I agree with you totally, it is way too bulky.

Roger at LensRentals says lenses that telescope when zooming aren't any worse culprits for dust ingress, so I don't see the down-side to the Canon design. I think they made a smart move. I still have a "full-size" 70-200 f.8 and won't be changing though (even if I went RF at some point), it's does everything I need and I can live with the size.

"Some of you like to call them dust pumps. That’s cool, too, although it’s incorrect. (We take care of over 20,000 lenses. The most common ‘dusters’ among current lenses all happen to be primes that don’t zoom at all.)"

"The ports under the filter ring are covered with a breathable filter. This would let air pass through as needed but would filter out dust particles."
https://www.lensrentals.com/blog/2019/12/the-not-very-long-awaited-teardown-of-the-canon-rf-70-200mm-f2-8-is/

It's the Z mount that allows elements to be placed a long way from the sensor without Vignetting for long lenses, unlike another smaller mount which must have the element close to the sensor to correct that problem. The Z mount allows the designer to place the rear elements in the best position optically with no compromises.

cosmicnode - I don't think so, as all the mounts work with adapted lenses, which have their last element some way from the sensor. The advantages of the new mounts are they can get the last element close to the sensor, but RF and Z both do that.

It’s not just about dust. A telescoping lens is less durable by nature. Roger Cicala is great, but this is physics. An object which is one piece is structurally more robust than an object made up of several pieces.

cosmicnode - err, light travels in straight lines through air, as long as you can see the whole sensor from the rear element of the lens you won't lose any light travelling to it, all adaptors will allow that.

Dr_Jon Correct light does travel in straight lines, But unless the adaptor has a "opening " in the rear of the mount of the adaptor larger than the diagonal of the sensor, then Light from the some areas of the rear element of a telephoto lens positioned around 100mm from the sensor cannot pass through the solid material of the mount to cover the corners of the sensor resulting in darkening of those corners . Google images of camera mounts of all the different camera makes for mirrorless cameras and only one has a mount smaller then the sensor, 4/3 like the Z mount are much larger than the sensor. The claims for Zed mount are probably relevant for most mounts as to the ability to design lenses without compromise.

A FF sensor is 43mm on the diagonal, I'm not aware of a mount that is narrower than that (the "Inner Diameter" being the clear opening and less than the more often quoted "throat diameter")?

Sony E 46.1mm
Nikon F 47.0mm
Pentax K 48.0mm
Leica L 51.0mm
Canon EF 54.0mm
Canon RF 54.0mm
Nikon Z 55.0mm

The advantage of a big diameter is you can get large optical elements really close to the sensor... although throat diameter is only one criteria here, "flange distance" (mount to sensor distance) matters, except some lens mounts can get optics closer to the sensor that that and some can't...

P.S. There's also "angle of incidence", which is the largest angle of light ray that can get from lens to sensor, but that relates to optical elements right at the back of the lens. However the numbers I've seen for that make assumptions about where that last lens element has to be, namely at the mount, which is often not true. (Plus digital sensors generally don't like light at big angles.)

Failing to realise the lens contacts align with the short side of the sensor is another sign of no Engineering experience...
CEng BTW...

and it always amazes me that a simple personal opinion is felt like a will to "impose limitations on other photographers" ...geez

it’s longer than the tamron because it’s an internal zoom and the tamron is not.

The 4/24-70 is a compact, affordable, collapsible design that prioritizes portability and light weight. The 2.8/24-70 is a no compromise design, large, heavy and expensive. I’d imagine that Nikon might release a 4/70-200 lens that is a good deal smaller, lighter, perhaps collapsible and much more affordable. Not on the road map but it makes sense they’ll get around to it.

That lens is not huge, it is big, but not huge. The 200-500 is huge or a 800mm prime. I love my F-Mount 70-200 2.8E FL and is the most used lens on my camera.

I'm not sure about it on the Z6.

You are absolutely right! Because it’s what equipment looks like is what really matters in photography.

This new mount is new to lens designers too. I have several f-mount lenses that are very recessed also . It’s about getting the light ray paths to converge properly onto the sensor. Right now this is what the know and will figure things out in the future of course.
I’ll bet this lens is phenomenal and much better than the f mount e fl vr version. I have it and like it but it hunts bad in back light situations. I’m super stoked about this lens

Unless you're an optical engineer I'm not sure how you can conclude that.

Just as a reference, both the Sony 70-200 GM and Canon 70-200 L IS II also have recessed rear elements as well.

“ Wasn’t the whole point of a larger mount to make lenses faster and smaller?”
The whole point of the larger mount and the shallower flange distance was to give lens designers more options in lens design formulas, and free them from the constraints of having to design a lens around the need for a reflex viewing system. Some lenses can be made smaller and some can be made faster, and some lenses can be redesigned to be sharper and have fewer issues with Optical aberrations, geometric issues like pincushion, barrel, or moustache (a combination of pincushion and barrel distortion at different focal lengths) distortions. Every lens design is a balancing act: a correction for one problem might lead to another problem that needs to be corrected.

“ Can’t they make this lens at least f2.0 for the same price as the older f2.8 simply due to the benefits of the larger mount?”

That would require much larger pieces of glass. More glass means a much larger and heavier lens, and a larger support structure to support the elements and groups and then you add in the complexities of very fast autofocus in a zoom lens, both of which are done by moving events and groups of elements relative to each other - in other words reconfiguring the optical path in the fly as fast as possible.

Pure marketing from Nikon. They haven’t made anything unique. Any lens that they have made that touts top optic’s is also top size. The 24mm F1.8 S is bigger and heavier than the Sony 24mm f1.4 GM. At least Canon is making halo products, Nikon doesn’t have anything interesting.

@Mr_Windbag
You complain about the Nikon being large, yet all of Canon's offerings are twice the size of Nikon...other than the 70-200 RF, which has the worst focus breathing (not a true 200 at its closest and softer than even their older lens).
What you fail to mention is that so far the Nikon Z 24 1.8S outperforms every other 24 on the market.
It's clear you are not the target market for this lens or any other Z product, so why are you still here?

@NexLupus

I suspect he has a massive case of insecurity. Why else be an unpaid, uncompensated #brandknocker?

Or he could just be a humanbot.

Would you really want to carry around much handhold and pay for an f/2.0 80-200mm lens? Have you ever looked at the size and weight specs and price tag of a 200mm f/2.0 lens?

@Mr_Win: the Nikon 24mm f1.8 is much lighter, much cheaper and better optically than the Sony 24mm f1.4, itself considered a remarkably good wide lens.

Most reasonable people would consider the Nikon to be an amazing achievement.

@ Mr_Win: yes, the Sony is 2/3 stop faster and 420gr. None of the other things you mention are accurate.

I fully acknowledge the value of the Sony lens. And I shoot both Nikon and Sony so I am objective about the value of both brands.

But the Bokeh of the 24mm f1.8 S is outstanding and its image quality best in class.

@ Mista Win:
Please do me a favour: Go to bed and dream of your Sonys.
Maybe some day they will deliver great lenses. Until then... DREAM ON!

physic of 200mm is 7.87402" min. the only way to reduce the carry length is use retracting or or a lenses that telescope as it zoom, incase like the nikon s 24-70 f4 or canon rf 70-200 lens.

Nikon did innvoate. Just not with this one.

@Mr_Windbag
You continue to say Nikon didn’t innovate...
Innovation for the sake of innovation is just plain dumb.
The new Canon 70-200 seems like a very nice lens, although not class leading in terms of optical performance and focus breathing (were it shows to be less sharp than it’s EF predecessor and with the most focus breathing of any modern 70-200 made).
Nikon took a different approach, the best optical quality with the least focus breathing of any modern lens, I would argue that this is very innovative.
The Nikon lens is best in class/reference glass, where the Canon is innovative key small.
It all depends on what you’re looking for in a70-200.

"@Mr_Win Nikon can’t innovate, this lens will sell like their system’s, it won’t."

Canon RF 70-200 has an innovated external AF that makes it 7 oz lighter than the Nikon, although no smaller when fully extended. But you sacrifice a lens that is less sharp compared to either Nikon E or Nikon Z 70-200. In fact the Nikon Z is the sharpest (read my lips sharpest) corner to corner, best parfocal lens ever made in the zoom range.

External AF system is so innovative that my $50 kit lens on my 20 year camera has this feature. And yes it collapses. I guess my kit lens is a pro lens just like the Canon. Yeah.

@JoeGuide
The Canon 70-200 f2.8 isnt that sharp

- nobody

Nikon focused on the lens being parfocal, and if true, that's generally why they are bigger. Canon made the sacrifice that I would gladly take to save that weight. The canon is robust and built from the ground up, unlike nikon and sony designed, which copied older models.

@JoeGuide
The Nikon Z 70-200mm isn't even parfocal. Really shows you don't know what you are talking about.

...and thank Kodak for bringing the camera to the masses... Leica for the 35mm format... Exacta for the SLR... Hasselblad for MF... Nikon for the 1st commercial DSLR and now the Z mount... ONE MOUNT TO RULE THEM ALL.

Hey Mista Win,

why so unhappy with Sony ? They have nice TVs.
Ok... also other stuff but nothing to write home about.

It can show things such as chosen aperture, focus distance, depth of field and focal length.

Focus distance.
Exakt focal length when matching zoom to odd primes like for example a 40mm lens or 60mm lens.
General work in the dark.

OLEDs has several advantages over LCDs for these applications even if they also have some downsides, I think you're seeing them used more often now because they've gotten a lot cheaper... The OLED panel only emits lights on the pixels that are displaying something, so just those lit up by a number, an LCD would be much more of a distraction in any semi-dark environment...

An LCD is also unreadable in a certain orientation while wearing polarized sunglasses due to the dual polarization cancelling out. LCD have been cheap for ages but those downsides (and possibly power use when the whole display needs to be lit up rather than just a few pixels) didn't make them too practical.

and probably much better...

@ElDiablo73

We should wait for comparison tests. Nikkor 85/1.8 and 35/1.8 show that Nikon lenses are not always better than Sony. FE70-200 with its 11 blade diaphragm has very good bokeh and great AF

@ hippo84 will see...

ps. With what Sony f/1.8 are you comparing them and where did you found that info? (thanks)

Mr_Win, I wish Tamron would produce the 70-180 f2.8 lens and the 28-75 f2.8 lenses for the Z cameras. I'm thinking of purchasing Sony -mount cameras just for these two lenses...

@Mr_Win
Except the Tamron is a 70-180 not 200 and who knows what it will actually be after focus breathing.
The Canon has the most focus breathing of any of the modern 70-200 2.8 lenses out and is optically inferior to it's DSLR counterpart (70-200 2.8L III).
The Nikon, based on initial testings and MTF charts, is a halo product with the best image quality and least focus breathing of any modern lens ever.
So...who's looking silly?

The Z Mount is a phenomenal design masterpiece. It can be used for APSC, full frame and the small medium format sensor size . It allows for adapting almost any lens system to it . And best of all super flexible for for designing optics to it . Optics with bright sharpe edges pushing into the new age of optic design better than ever before .

.

@NexLupus 10% more range can easily be made up with a crop, the Nikon weighs 75% more at that weight, you can carry a 28-75 f2.8 AND 70-180 f2.8 for the equivalent weight. Oh, and any Sony body and tamron lens would smoke the Nikon with AF... If you insist on performance as a spec.

I fully agree. A 2.8/70-200 with a constrained to make use of a high MP FX sensor in the 40-60MP range must be of that size. If people complain about size the should not look into the option of a 35mm sensor system with autofocus.

Manual focus lenses you can design more compact, since the human has more power and is slow. An AF lens requires small moving internal lens elements that they can be moved fast: You buy the Af with lots of lens aberration which you have to correct with extra lens elements.
Fast AF+ Fast lens + large sensor= heavy lens for high IQ.

This is one of the flagship lenses of the Z system and that must deliver very high IQ suitable for the these very high MP sensor.

Based on size, yes....
Based on optical performance, no...
The New Nikon Z 70-200 2.8S is on a completely different level optically.

Based on quickest time to needed to fix a defect???

@Jack Jian

I guess the RF lens wins hands down if you are shooting an R body.

@Jack Jian

The EF 70-200/2.8L III was/is not THE top performer. According to the MTF tests done by lensrentals.com (which I happen to trust), the Nikon 70-200/2.8E FL was superior to other lenses among its class. The Z 70-200/2.8 S has by fair margin better manufacturer MTF tables than the FL version.

Also, when using the RF version at shooting configuration @ 200mm including the hood, it seems to be tiny bit longer (= 282.3mm) than the Z 70-200/2.8 S, even more so when combined with the body. Remember that the Z mount has 4mm shorter flange (16mm vs 20mm), and the Z bodies are thinner than R bodies.

And finally, maximum resolution with the R system is still only 30MPix and lower DR compared to the 45Mpix of the Z7.

Nobody is forcing anyone to carry this around. Either buy it and use it or not. Who cares whether you want it or not?

Try and shoot a hockey game or an indoor swim meet, or an indoor basketball game with the Z 50 and the long kit zoom and then shoot it with the Z 6 and this 70-200/2.8 S. You'll see the difference immediately.

Funny how so many nitpicking tech heads are able to distinguish a 0,5 EV difference in DR capabilities between two bodies, but can cope with f/4 or even slower lenses but unable to notice what they miss with them...

Of course, slower lenses are now no more slouches, but frankly, claming you just need to crank up ISO 1, 2 or 3 full EV and slower lenses are perfect... Sorry, but you really have ZERO clues what a fast lens is usefull for, nor care at all at DR nor noise control !

Just accept you don't need them instead of claiming lousy assumptions.

And frankly, if you cannot carry more than 2kg of photocameras, you really just stop shooting with anything else than a smartphone. It is already far more capable than what you are really needing.

I think only pros would want to use such a lens.

@stevevelvia50 I guess that tells more about your photographic needs and uses than anything else.

@Impulses : do you really want to make us believe those Z lenses will be 15 hours per day, 6 days per week, for months and display the same information in order to be burnt like you are dreaming for ?

Could you please find something else than really strange and missguided usage to hate those OLED panel ? Or it is just because you have to make a critique and you never intended to buy anything from nikon in the first place ?
You should really keep buying SONY devices, and used them instead to have to look anywhere else. You really seems to not be fully satisfied by SONY for a really strange reason.

@PCPics... I'd say if you enjoy your lens for 10 years and then get it serviced by Nikon the OLED panel will look just peachy and it will be well worth the cost.

I'm not sure why you think my comment was hiding some sort of an agenda, I actually have a camera with an OLED EVF and I even started the I'd be more concerned about the effects there than on a simpler display... I also own a 65" OLED TV FWIW (LG C9), not to mention a phone. Burn is a very real concern tho, and it's not just about the total use time but about the static content being displayed when it is used.

LCD has it's own long term issues and down sides mind you, the polarization conflict when wearing sunglasses makes OLEDs much more appealing for quick glance displays or EVF, and I've actually seen instances of literal burn spots on LCDs caused by the sun and extreme diopter settings (happened to some older Oly bodies). No display tech is perfect, put down your pitchfork, I was just sharing factual info and concerns.

There is two separate L-fn buttons which you program to do AF-lock or other functions.

I am not a professional, and for me compactness and weight are at least as important as robustness. Looking forward to Tamron 70-180mm f/2.8 tests.

You spelled “buy” wrong. How am I supposed to take your post seriously? How is what Canon did decades ago relevant to the release of this lens? You know that the Sony version is bigger, heavier and not as optically good, right?

Canon RF version will outsell Nikon 10:1 bare minimum. Nobody wants that boat.

@QuarryCat: what weak close-up opportunity are you talking about.

We are not speaking about a macro lens, are we?

The Canon has a higher magnification ratio of x0.23 vs x0.2 only because it has a closer focusing distance at 200m of 0.7m vs 1m for the Nikon. The thing being that 200mm at 0.7m is useless for most of the practical applications of such a lens.

All this shows is that the Canon has more focus breathing at very close range.

At a more useful distance of 1 to 2m, the Nikon has more magnification that the Canon beause it has less focus breathing.

Anyway you look at it, the Canon's only advantage is 300gr less and a more compact package when not in use. For all other aspects related to photography the Nikon is the better option. I guess that it depends whether you carry a lens to save weight or to take pictures.

Cheers,
Bernard

@QuarryCat: apologies, but have you ever shot with a 300mm f2.8 or 400mm f2.8 at all or for any extended period of time?

I have and I can tell you that these lenses are used on a monopod 90+% of the time. So the convenience of a 120-300mm f2.8 trumps a lighter weight lens any day of the year for people actually working with such lenses.

For the very same reason that people raved about the Nikon 200-400mm f4 for 9 years until Canon caught up with their version with integrated converter. That Nikon has now caught up with. And users are now raving about these lenses and preferring them over 400mm f2.8 because flexibility is more important than one extra stop in many cases.

The only problem with the 120-300mm f2.8 it its price, but that's life. You want the best be ready to pay for the best.

@QuarryCat : "
the big conquerer of Nikon... you write here from nowhere and you assume most photographers take more bad pictures because of using Sony GM or Canon L lens or even Fuji instead of Nikon S?".

Don't put these words in my mouth please, I have never said that nor do I think it.

I perfectly know it's possible to take great pictures with these lenses, they will just not be at the same level of technical excellence or look than those captured with the Nikon.

It has become a place for mouth breathers that’s for sure. It often doesn’t even take more than 10 posts for a lame critique and a corresponding rebuttal.

It's become pretty toxic. I remember when this community was about photography, technology, and excitement. Now it's just a bunch of people being brand loyalists. To be honest, I'm tired of trying to have constructive, objective conversations here as they just become polluted. Mike, you know I'm getting too old for this ;) I think I'm moving on.

Cheers

I hear you. I really only speak up when people who have zero experience with the gear I use try to speak with authority. It gets exhausting correcting the misinformation.

@NEXLupus

Can you link to the MTF. I'm interested in the performance of this lens versus the 70-200/2.8 Panasonic L.

Size is great... as a 3rd priority behind image quality and robustness.

When my clients look at the images they don't care about how compact the lens was... they care about the results.

Besides, size and weight should be considered at system level, and when you compare a corresponding set of lenses between S and RF systems, they gap is close to zero. For example, the 24-70mm f2.8 S is 100gr lighter than the RF.

Besides, Canon has nothing to put in front of the amazing 85mm f1.8 S which offers amazing image quality and more than enough background isolation for actual photography. You are stuck with a, great, 85mm f1.2 that most people shoot at f2.0-2.8 most of the time.

MTF figures here : https://imaging.nikon.com/lineup/lens/z-mount/z_70-200mmf28_vr_s/spec.htm

Not a good idea to compare published MTF curves between different manufacturers, at least not in minute details. Methodology may differ.

@MayaTlab0: well, the E FL was already clearly superior to the Canon 70-200mm f2.8 III released after it. All the S lenses are clearly superior to the F ones. Canon shoot them selves in the foot image quality wise by choosing a collapsible design. If anything I would expect the S lens to be even more superior compared to the RF than the MTF charts indicate.

@RubberDials
Here is a direct comparison on NR that also shows the difference in optical formula between the 2 lenses, for those that keep saying that it is a rebadge of the F mount version.
https://nikonrumors.com/2020/01/08/nikkor-z-70-200mm-f-2-8-vr-s-vs-af-s-nikkor-70-200mm-f-2-8e-fl-ed-v-lens-comparison.aspx/

The Canon has the most focus breathing of any 70-200 lens made.
You can’t dismiss that with “no one will ever notice .”
The New Canon RF 70-200 is softer than its EF counterpart, so it will definitely be noticeable against the Z 70-200.
But hey if size is all that matters, you have your lens... but to say that this new Z 70-200S is a fail is just an ignorant statement.

@Mister Anders0n: sure, all lenses are the same... Or not... I can personally clearly see the difference between my 85mm f1.8 S and the 85mm f1.4 AF-S even in 2000 pixel wide images. Detail is part of it, but there is lack of CA, especially LOCA, astigmatism, flare control,... all aspects that are very visible in web side images.

@Mister_Anderson
Sorry Neo, but not all of us are broke and still living with mom.

Just because you can’t see the difference doesn’t mean others can’t, or maybe you are making excuses because you can’t afford the new lenses.
Either way, the new Nikon lenses are quickly becoming THE reference lenses in every category regardless of whether you see it or not...

I bet I've got a lot more cash lying around than you do. I'm just not a sucker. It's not going to matter how good the S lenses are because Nikon won't be around much longer. No one is buying them, and no one is buying the Z bodies. And no, the 5 people here on the forum who did don't count.

Ouchhhh! You got me!!!
I notice that you didn't refute that you still live with mommy...LOLOLOL

@Mister Anders0n: ok, so you see to agree now that the S lenses are excellent, but that 1. their excellence is not relevant to your photography, your call, I have no issue as long as you are looking at this objectively, 2. nobody is buying into the Z system. I have an issue with this one but fine... it seems clear by now that you are just another of those boys...

You're thinking of Sony cameras. It's takes a lot to break the mount on a Nikon.

Canon is what? Right? Huh?
Smoked weed, eh?

1. Break. 2. Canon doesn’t work on Nikon & vice versa. 3. The Nikon’s MTF’s show it to be the sharpest 70-200 yet. So. There’s that.

Sarcasm.

The RF versions seems rather huge for a 70mm f2.8 lens ;)

It is also obvious that the RF must have huge amount of focus breathing at 200mm setting when pulling to minimum focus distance. MFD is 0.7m (or measured just under) while magnification is only 0.23x. These numbers gives focal length of only 105mm???

I'd like to know what are measured real focal lengths @ infinity for these lenses. Canon might well be the shortest, so that they could bring the size down little bit compared to others.

@misspiggy01 i agree, they are boring

Yes. Uncertainty: "Nikon initially stated that the lens was parfocal (maintaining focus distance, even when you zoom the lens), which is useful for videographers. It has subsequently retracted this claim, so we'll have to wait to see how it behaves, when final versions go into circulation." That's why I ask: "Is there still a chance that it will be parfocal...?"

I believe that the camera communicating with the lens was supposed to focus as the focal lenght was changed and it isn’t working at this time . True parfocal cinema lenses are so expensive to make especially a zoom .

Street with a 70-200mm 2.8?

Sony is so good it brainwashed their users to think bigger is smaller.

An UWA zoom is my primary lens for street photography, something along the lines of 18-35mm FX. I've never been interested in standing off at a distance sneaking shots of unsuspecting people. . .

@nexlupus you did loose some cells. The nikon Is bigger and wider. 8.66 x 3.5 vs 7.87 x 3.46. Plis thehood is bigger. They weight the same

I do street portraits with a Nikon 200 f/2.0 , never have a problem and I walk out with the IQ I want.
I hear the WTs complaining about weight-size all the time and I Am sure it matter to them for whatever reason.

Don't know anybody who uses a 70-200 for street...

Lens construction is totally different than the F mount versions.

No, there are glass elements in what looks like a built in FTZ adapter. It's not empty/hollow, it's functional.

There rear elements area somewhat recessed also on the AF-S FL version for F-mount, even more so with 70-200 f/4G.

The optical construction of Z vs FL looks somewhat similar for the front group (Z having SR element and more ED elements), but looks compeletely different in the middle and near the lens mount. So it is safe to say that Z is compeletely new design.

The recessed element makes sense for the focal length range and leaves room for a future high quality teleconverter to protrude into the lens.

@artnaz If you look at the design of the Sony 70-200 f2.8 GM lens, it has a similar space in the rear of the lens. When it first came out, people were asking the same question you are about why the space was there. Then the 1.4x and 2x teleconverters came out and they slot forward into the rear of the lens such that the glass element of the teleconverter is very close to the recessed rear element of the lens. Its was clear they were designed together. I predict that when Nikon releases their teleconverters, they will have a similar design.