Why are primes larger and heavier than Fs?

[ClaudiusTheGod]

It's probably because of the flange distance of the Z. The flange distance of a DSLR is around 44mm. You can make a very simple lens design with a focal length of around that mark (so 35mm, 50mm) because you don't need either a retrofocus or telephoto lensgroup, which adds a lot of lens elements. So for the Z system, a 16mm lens would probably be very easy to make and small, but a 50mm requires a telephoto design now, so that adds bulk. You could take the DSLR lens design and add the 30mm that makes up the difference in FD as empty space, but that would make an even bigger lens.

--
http://www.flickr.com/photos/zonoskar/

are you saying that the reason the nifty fifties were so small in cameras with a mirror was because of the longer flange distance?

I always assumed it was small because it was the focal length close to the length of the diagonal of the frame- the easiest one to design.

 

[VBLondon]

It is impossible not to mention other brands, and I hope you don't think this is trolling. Fuji and the MFT systems do offer small fast primes. Ok not as fast as Nikon Sony or Canon fast primes (for the same angle of view and depth of field).

There is a point at which one must ask oneself - and I am asking myself this- If I'm the kind of photographer that wants a 50 f2 on a mirrorless body and wants it small- then I have to look at an x-pro2 and 35 1.4 - can be had used and in almost pristine condition for about £1200.

If price isn't a factor, then a leica cl and 35 1.4 could be had for £4000, but that lense sticks a little too.

Yes yes the Nikon is a far better camera. I use fuji and Nikon and can say with confidence that even my newest and beloved X100f is a complete and utter PITA to use. But they are small and they are sharp and they are reasonably capable.

I totally agree with you. My interest in FX has always been low light ability, DoF control and DR, in that order; plus (in DSLRs) the large OVF, and not the test-chart optical perfection that seems to be the main priority of many internet writers and forum posters.

"Traditional" FX lenses, the AFDs and older AFS in particular, provide a fantastic combination of speed and compactness and sometimes low cost. I can live with the optical compromises - stopped down, they are minimal and wide open I rarely need edges sharp, usually I want blur in the background. More recently, the AFS-G f1.8s have been a reasonable compromise. It's meant that FX is the ideal format for my needs, because the fast Fuji and m43 lenses are still equivalently slower and as big and sometimes more expensive than the FX F mount choices available.

But the size of these new primes means those days are over. I don't see Nikon ever bothering with compact fast primes again - not with 50 other lenses they have to fill in the Z roadmap!

I really like Nikon gear and I like new technology, so should be an ideal customer for the Z series (as a mild hobbyist I don't really care about the stuff others are screaming about - single card slot etc). Like you, I have an X100F - a lovely device that produces great output, but I find all the secondary menu-driven controls difficult and confusing - there's always a mode conflict between one setting somewhere and something I am trying to do. But, if I want compactness and light-gathering in a MILC, it looks as if the Fuji f1.4s might be a better option than these (I am sure optically wonderful) big f1.8s from Nikon.

 

[zonoskar]

It's probably because of the flange distance of the Z. The flange distance of a DSLR is around 44mm. You can make a very simple lens design with a focal length of around that mark (so 35mm, 50mm) because you don't need either a retrofocus or telephoto lensgroup, which adds a lot of lens elements. So for the Z system, a 16mm lens would probably be very easy to make and small, but a 50mm requires a telephoto design now, so that adds bulk. You could take the DSLR lens design and add the 30mm that makes up the difference in FD as empty space, but that would make an even bigger lens.

are you saying that the reason the nifty fifties were so small in cameras with a mirror was because of the longer flange distance?

I always assumed it was small because it was the focal length close to the length of the diagonal of the frame- the easiest one to design.

A lens with a focal distance exactly of the flange distance could make do with just one lens element, because this lens element focuses light a the focal distance behind the lens, which is exactly the flange distance. This is too simple of course because you'd not correct for various aberrations and you won't account for mechanical stuff like AF.

The diagonal of the 35mm sensor somewhat dictates the flange distance as it dictates the size of the mirror. This thread is a good read: https://www.dpreview.com/forums/thread/3595268

 

[TN Args]

I am glad that you answered your own question, i.e. "better".

 

[JimKasson]

It's probably because of the flange distance of the Z. The flange distance of a DSLR is around 44mm. You can make a very simple lens design with a focal length of around that mark (so 35mm, 50mm) because you don't need either a retrofocus or telephoto lensgroup, which adds a lot of lens elements. So for the Z system, a 16mm lens would probably be very easy to make and small, but a 50mm requires a telephoto design now, so that adds bulk.

Telephoto designs have negative elements on the sensor end of the lens to allow the lens to be physically smaller than the focal length would otherwise dictate. I think that you are talking about some other kind of design, probably retrofocal, or inverted telephoto.

https://en.wikipedia.org/wiki/Angénieux_retrofocus

 

[rhlpetrus]

Because you might get it?

Just yesterday before the press event almost all that everyone wanted to talk about was how the wider opening of the mount would allow for better image quality, specifically calling out corner performance.

That directly implies that there will need to be wider glass elements. This 50mm f/1.8 also has 12 elements in 9 groups, far more than you've ever heard of in that FL and aperture class. More mass of glass and more area to polish drive up production costs, and its $600 price in this product class reinforces that point.

Nikon is making a bold claim for this lens:

"A 50mm f/1.8 like no other / Performance that totally defies expectations

Empowered by the Z system's larger mount, shorter flange distance, raw imaging power and video capabilities, the NIKKOR Z 50mm f/1.8 S will redefine your notion of what a 50mm f/1.8 lens can do"

Lenses with similar performance aspirations are available from Zeiss and Sigma, and they too are large and heavy.

If the claim is supported by great performance, no problem, maybe they will be actually better wrt bokeh and other characteristics, like CA. And, likely, we will see more compact lenses coming from both Nikon and 3rd party makers. Not worried, actually, just curious, here. Thanks for quote.

Sony's FE system seems to be geared to offering photographers basically the same kind of lens lineup as they would expect on DSLR and I spose that makes sense as Sony doesn't have much market share with FF DSLRs. Nikon on the other hand already has a good part of that market and they perhaps take the view that if people want high quality F/1.4 primes they will buy a D850 or D750. SO instead of just offering exactly the same on the Z-mount offer something that caters more directly to that systems benefits

A significant draw of mirrorless is still size/weight saving though so you could argue that many people will want really high quality primes that offer that. I mean if your shooting on the FE system and want high quality 35mm and 50mm primes then your having to buy F/1.4 options that cost around $1500 are quite long and weight about the same as the camera itself.

With Nikon you might well be looking at lenses that offer the same kind of quality but cost half or less the price and weigh half the amount. For that I suspect many people would be willing to give up 2/3rds of a stop of light.

As to why they don't make them smaller I would argue theres probably a limit beyond which users don't care as much. So making the 24-70mm as small as possible is an advantage but making the 35mm and 50mm smaller possibly damaging there performance wouldn't be an advantage, hence they end up a similar kind of size.

Only that the 35 and 50 are much larger than the 1.8 AF-S versions. I hope Nikon brings in some pancakes at some point, even if not filled with AF systems for video and of top-notch IQ. Just simple cheap primes to use lightly on these cameras.

 

[rhlpetrus]

I am glad that you answered your own question, i.e. "better".

Yes, but I still hope for some cheap, light, maybe "poorer" re IQ, and with less sota AF for video, prime lenses to go with these cameras, in WA and normal FLs. Just update the f/2.0 D primes to Z mount, with basic AF.

 

[jlabelle]

If the claim is supported by great performance, no problem, maybe they will be actually better wrt bokeh and other characteristics, like CA. And, likely, we will see more compact lenses coming from both Nikon and 3rd party makers. Not worried, actually, just curious, here. Thanks for quote.

Sony's FE system seems to be geared to offering photographers basically the same kind of lens lineup as they would expect on DSLR and I spose that makes sense as Sony doesn't have much market share with FF DSLRs. Nikon on the other hand already has a good part of that market and they perhaps take the view that if people want high quality F/1.4 primes they will buy a D850 or D750. SO instead of just offering exactly the same on the Z-mount offer something that caters more directly to that systems benefits

A significant draw of mirrorless is still size/weight saving though so you could argue that many people will want really high quality primes that offer that. I mean if your shooting on the FE system and want high quality 35mm and 50mm primes then your having to buy F/1.4 options that cost around $1500 are quite long and weight about the same as the camera itself.

That is simply not true. Indeed, this was the philosophy of Sony with their first 55mm 1.8 and 35mm 2.8.

The FE 55mm is stellar. Here is some of the preview comment:

"

The scale of Sony's achievement here becomes clear when comparing the FE 55mm F1.8 directly to the Zeiss Otus 55mm F1.4, which lays a strong claim to being the best lens for which we have test data. The Otus still just about comes out on top - it measures as slightly sharper wide open - but it's unlikely any difference will be particularly visible in real-world photography. The Otus also just about wins out on chromatic aberration and distortion, but overall the Sony can certainly wear its Zeiss badge with pride.

Compared to the Canon EF 50mm f/1.8 II or Nikon AF-S Nikkor 50mm f/1.8G, the Sony is quite simply in a different class"

And the 35mm is also excellent...for 120g and its almost pancake size:

"From the lab test results, the Sony FE 35mm F2.8 ZA is a pretty impressive little lens. It doesn't quite attain the same heights as the FE 55mm F1.8, but it's still impressively sharp. It's also very small and portable"

Or Image Ressource:

"The new Sony FE 35mm ƒ/2.8 ZA Zeiss Sonnar T* lens is another fantastic fast prime lens for the Sony A7R and A7.

Optically, this lens is a stellar performer, as many Zeiss lenses are, with very sharp images on both the new full-frame cameras. Other factors like chromatic aberration and distortion are practically nonexistent..."

I applaud Nikon to take the same route as Sony as this is what people expect first (high quality small lens reasonably fast).

I think that is just missing a pancake to make a very portable setup and do not understand the priority in their roadmap for f/2.8 versions of the 70-200 and 12-24...

 

[G1Houston]

[No message]

 

[Ellis Vener]

The 50mm is Z 76x87mm (w/l), 415g

The classical 50mm f/1.8 AF-S is 53x72mm and 186g

This is a huge difference in all aspects, defeating, in my view, the prospect of a lighter alternative. Silent motor? Same design with internal adapter for smaller flange distance?

The difference for 35mm is there, but not as much:

The 35mm Z is 73x86mm, 370g

The 35mm f/1.8 AF-S is 72x72mm and 305g

I'd like comments, but, please, other brand trolls and anti-ML nikonians could stay away, this forum is for those interested in the Z system, not a place for haters.

--
Renato.
http://www.flickr.com/photos/rhlpedrosa/
OnExposure member
http://www.onexposure.net/
Good shooting and good luck
(after Ed Murrow)

If the 50mm f/1.8 performs the way it has been touted, the lenses to compare it to are the Zeiss OTUS and the Sigma 50mm /2.4 Art, both of which are pretty chunky. I’ve shot with the OTUS and the Sigma - and bought the Sigma.

--
Ellis Vener
To see my work please visit http://www.ellisvener.com
Or on instagram @therealellisv

 

[fad]

The 50mm is Z 76x87mm (w/l), 415g

The classical 50mm f/1.8 AF-S is 53x72mm and 186g

This is a huge difference in all aspects, defeating, in my view, the prospect of a lighter alternative. Silent motor? Same design with internal adapter for smaller flange distance?

The difference for 35mm is there, but not as much:

The 35mm Z is 73x86mm, 370g

The 35mm f/1.8 AF-S is 72x72mm and 305g

I'd like comments, but, please, other brand trolls and anti-ML nikonians could stay away, this forum is for those interested in the Z system, not a place for haters.

If the 50mm f/1.8 performs the way it has been touted, the lenses to compare it to are the Zeiss OTUS and the Sigma 50mm /2.4 Art, both of which are pretty chunky. I’ve shot with the OTUS and the Sigma - and bought the Sigma.

I have the 55mm Otus and the excellent Voigtlander 40/2 and look forward to using them along with the new 50/1.8 and other Nikons. But what am I supposed to do when I want an AF pancake?

--
Frank

Sidewalk Shadows | A street photography blog

Photos look better in Original Size
Shot in downtown Manhattan, mostly

 

[rhlpetrus]

The 50mm is Z 76x87mm (w/l), 415g

The classical 50mm f/1.8 AF-S is 53x72mm and 186g

This is a huge difference in all aspects, defeating, in my view, the prospect of a lighter alternative. Silent motor? Same design with internal adapter for smaller flange distance?

The difference for 35mm is there, but not as much:

The 35mm Z is 73x86mm, 370g

The 35mm f/1.8 AF-S is 72x72mm and 305g

I'd like comments, but, please, other brand trolls and anti-ML nikonians could stay away, this forum is for those interested in the Z system, not a place for haters.

If the 50mm f/1.8 performs the way it has been touted, the lenses to compare it to are the Zeiss OTUS and the Sigma 50mm /2.4 Art, both of which are pretty chunky. I’ve shot with the OTUS and the Sigma - and bought the Sigma.

I have the 55mm Otus and the excellent Voigtlander 40/2 and look forward to using them along with the new 50/1.8 and other Nikons. But what am I supposed to do when I want an AF pancake?

I hope a pancake will eventually be made, as system develops. Maybe some 3rd party maker does the AF small lens. 40mm f2 would be good for me.

--
Renato.

Renato Pedrosa

Explore Renato Pedrosa’s 937 photos on Flickr!

www.flickr.com

OnExposure member

http://www.onexposure.net/

Good shooting and good luck
(after Ed Murrow)

 

[rhlpetrus]

The 50mm is Z 76x87mm (w/l), 415g

The classical 50mm f/1.8 AF-S is 53x72mm and 186g

This is a huge difference in all aspects, defeating, in my view, the prospect of a lighter alternative. Silent motor? Same design with internal adapter for smaller flange distance?

The difference for 35mm is there, but not as much:

The 35mm Z is 73x86mm, 370g

The 35mm f/1.8 AF-S is 72x72mm and 305g

I'd like comments, but, please, other brand trolls and anti-ML nikonians could stay away, this forum is for those interested in the Z system, not a place for haters.

If the 50mm f/1.8 performs the way it has been touted, the lenses to compare it to are the Zeiss OTUS and the Sigma 50mm /2.4 Art, both of which are pretty chunky. I’ve shot with the OTUS and the Sigma - and bought the Sigma.

MTF graphs look very impressive, samples here at DPR also. And the Nikon brochure emphasizes lenses from the start.

https://cdn-4.nikon-cdn.com/e/Q5NM96RZZo-RRZZFeeMiveET0gVQ--AxJI7g-xcLVNVcp7mdwZQz5w==/Misc/Z7_Z6_Brochure.pdf

--
Renato.

Renato Pedrosa

Explore Renato Pedrosa’s 937 photos on Flickr!

www.flickr.com

OnExposure member

http://www.onexposure.net/

Good shooting and good luck
(after Ed Murrow)

 

[ClaudiusTheGod]

The 50mm is Z 76x87mm (w/l), 415g

The classical 50mm f/1.8 AF-S is 53x72mm and 186g

This is a huge difference in all aspects, defeating, in my view, the prospect of a lighter alternative. Silent motor? Same design with internal adapter for smaller flange distance?

The difference for 35mm is there, but not as much:

The 35mm Z is 73x86mm, 370g

The 35mm f/1.8 AF-S is 72x72mm and 305g

I'd like comments, but, please, other brand trolls and anti-ML nikonians could stay away, this forum is for those interested in the Z system, not a place for haters.

If the 50mm f/1.8 performs the way it has been touted, the lenses to compare it to are the Zeiss OTUS and the Sigma 50mm /2.4 Art, both of which are pretty chunky. I’ve shot with the OTUS and the Sigma - and bought the Sigma.

I have the 55mm Otus and the excellent Voigtlander 40/2 and look forward to using them along with the new 50/1.8 and other Nikons. But what am I supposed to do when I want an AF pancake?

I hope a pancake will eventually be made, as system develops. Maybe some 3rd party maker does the AF small lens. 40mm f2 would be good for me.

well i hope so to, but what will they say? we made the 50 1.8 too big and now we've made it smaller?

or they could say- hey buy this smaller prime, its worse than the others! but I doubt they'll say that at.

no, they'll do like sony did with the 35 and make it 2.8

and that is going to give a d610 with a 50 1.4 a full two stops advantage size for size- which I expect it would be

or more bizzarly a fuji apsc body, with its 35 1.4 or 24 1.4, 2/3rds of a stop equivalent advantage!

 

[rhlpetrus]

The 50mm is Z 76x87mm (w/l), 415g

The classical 50mm f/1.8 AF-S is 53x72mm and 186g

This is a huge difference in all aspects, defeating, in my view, the prospect of a lighter alternative. Silent motor? Same design with internal adapter for smaller flange distance?

The difference for 35mm is there, but not as much:

The 35mm Z is 73x86mm, 370g

The 35mm f/1.8 AF-S is 72x72mm and 305g

I'd like comments, but, please, other brand trolls and anti-ML nikonians could stay away, this forum is for those interested in the Z system, not a place for haters.

If the 50mm f/1.8 performs the way it has been touted, the lenses to compare it to are the Zeiss OTUS and the Sigma 50mm /2.4 Art, both of which are pretty chunky. I’ve shot with the OTUS and the Sigma - and bought the Sigma.

I have the 55mm Otus and the excellent Voigtlander 40/2 and look forward to using them along with the new 50/1.8 and other Nikons. But what am I supposed to do when I want an AF pancake?

I hope a pancake will eventually be made, as system develops. Maybe some 3rd party maker does the AF small lens. 40mm f2 would be good for me.

well i hope so to, but what will they say? we made the 50 1.8 too big and now we've made it smaller?

or they could say- hey buy this smaller prime, its worse than the others! but I doubt they'll say that at.

no, they'll do like sony did with the 35 and make it 2.8

and that is going to give a d610 with a 50 1.4 a full two stops advantage size for size- which I expect it would be

or more bizzarly a fuji apsc body, with its 35 1.4 or 24 1.4, 2/3rds of a stop equivalent advantage!

Advantage? For low light, yes, but most of my shooting is in daylight and f/4-f/8. And with these cameras that shoot well at 12800, f/2.8 is already excellent. When one needs it really faster, grab the 0.95 !

 

[rhlpetrus]

They've stated that they are going for the highest optical quality and excellence in the Z mount lenses.

Have a look at the Zeiss Otus lenses, have a look at the Sigma Art lenses. They're all much larger than traditional optical designs for their focal length and max. aperture.

The new mount will allow things that they've had to compromise on before. For a FX camera I applaud their work in trying to create the best lenses they can.

I just wonder if we'll see a DX mirrorless body series, perhaps in a different form factor (rangefinder style, etc), that do come with a set of small and compact lenses (perhaps slower max. apertures) that maintain high optical quality. Something along the lines of the Fuji X-E3 or X-Pro2).

 

[Hoskt]

The OP said "haters" are not allowed on this thread. I suppose the definition of "hater" is as fluid as the meaning of "hate speech" is these days. Some people cannot stand opposing views, even when discussing photography

Am I a "hater"? I've used Nikon for more than 35 years, and recently moved to Sony and Fujifilm.

If I make negative comments, some might call me a "hater", but maybe that's in keeping with everything being called "hate speech" these days if it disagrees with you.

If I digress, it's only because the OP started this thread with that provocative comment, so my reply is on the OP's point (so, dear moderator) please don't delete my post.

Some people are shocked at the size of these Z lenses. It is the bursting of the bubble of expectations that mirrorless would provide nice compact, light-weight lenses. To come back to reality, you only have to see Sony's range of massively chunky and heavy prime FF lenses.

I grew up with nice compact Nikon AI-S lenses, 28/2.8, 35/2.0, 50/1.4, 105/2.5 full frame lenses, and most of Sony's prime lenses - at those apertures - are larger, chunkier and heavier.

When you see how compact those Nikon AI-S manual lenses were, you have to find out why even Zeiss manual primes for Sony E-mount are so gigantic.

It's seems it's because mirrorless FF tends to produce very large lenses. What you lose on lens mount distance, all that distance gets added to the lens (in simplistic terms). So the FF mirrorless lenses tend to be larger than the equivalent F mount.

That's why I've settled on APS-C mirrorless as the sweet spot for people who want lightweight and compact, with decent image quality.

I think quite a few people, who are new to mirrorless, are going to be in for a shock at how large these Z lenses are going to be.

The fact is, these lenses showcase the future direction of where the Z lenses are going.

The Z hype and marketing promise compact, fast primes - but in Nikon's 3 year roadmap, you don't see any fast primes. Why?\

And even the hype about the large Z mount enabling Nikon to produce super-fast lenses, well, from the size of the Noct Nikkor - and their inability to provide autofocus with that lens - you can see where the future leads to with the Z mount.

 

[jlabelle]

Some people are shocked at the size of these Z lenses. It is the bursting of the bubble of expectations that mirrorless would provide nice compact, light-weight lenses. To come back to reality, you only have to see Sony's range of massively chunky and heavy prime FF lenses.

I grew up with nice compact Nikon AI-S lenses, 28/2.8, 35/2.0, 50/1.4, 105/2.5 full frame lenses, and most of Sony's prime lenses - at those apertures - are larger, chunkier and heavier.

When you see how compact those Nikon AI-S manual lenses were, you have to find out why even Zeiss manual primes for Sony E-mount are so gigantic.

It's seems it's because mirrorless FF tends to produce very large lenses. What you lose on lens mount distance, all that distance gets added to the lens (in simplistic terms). So the FF mirrorless lenses tend to be larger than the equivalent F mount.

I don't know why we are at it. That is like those endless troll stating that "f/2 is f/2 is f/2" to try to oppose the equivalence discussion.

So here, I will make the comparison with Canon lenses because I had 15 years of experience and ownership on those.

Sony FE lenses ARE either

lighter / smaller (with Sony body, you save 26mm on the total length for same lens length compared to a Canon body) than DSLR counterpart:

• 24-70 f/4 IS: 426g and 94.5mm (FE Sony) instead of 600g and 93mm (EF Canon) so 24,5mm shorter in total
• 16-35 f/4 IS: 518g and 98.5mm instead of 615g and 112.8mm
• 11/12-24 f/4 IS: 565g and 117mm instead of 1.18kg and 132mm
• 90-105mm macro f/2,8 IS: 602g and 130mm instead of 625g and 123mm
• 24-105 f/4 IS: 663g and 113mmm instead 795g and 118mm
• 100-400 f/4,5-5,6 IS: 1.4kg and 205mm instead of 1.64kg and 193mm

• 24-70 f/2,8: 886g and 136mm instead of 805g and 113mm
• 16-35 f/2,8: 680g and 122mm instead of 790g and 127mm
• 70-200 f/2,8 IS: 1,48kg and 200mm instead of 1.48kg and 199mm35mm f/1,4: 630g and 112mm instead of 760g and 106mm
• 85mm f/1,8: 371g and 82mm instead of 425g and 72mm : and the Sony FE is much better than the Canon in term of quality. It is better at f/1,8 onward than the 85L
• 85mm f/1,4: 820g and 107mm instead of 950g and 105mm
• 28mm: f/2, 200g and 60mm instead of f/2,8, 260g and 51mm

or so much better than they do not compare:

• 55mm f/1,8: 281g and 70mm. This is the same kind of comments we have today with Nikon Z version. So it is lighter than the Canon 50mm f/1,4 but 20mm longer so all in all, it ends up being as long on the body. But the Zeiss 55mm trounces the Canon big time.
  If you want in the same league, Sony offers the Sony 50mm f/1,8 for 200$ and 100g less than the Canon and smaller package.
• 50mm f/1,4: 778g and 108mm instead of 290g and 50mm : yes, the Canon is much lighter and smaller, but the Sony destroys the Canon. It is not even in the same league. It is much better than the 50L indeed.

So it IS true that mirrorless is bringing much weight saving and a smaller package.

Here, without being exhaustive, this is a saving from a few g...to 100-200g (24-105, 16-35, 24-70, 85 1,4....) …to more than half a kilo (12-24).

This together with the body, it means that everytime you shoot, you are carrying 400g to more than half a kilo less than with the DSLR.

And if you have several lenses, your bag can be 1-2kg lighter.

If it is not a major advantage, I don't know what it is.

That's why I've settled on APS-C mirrorless as the sweet spot for people who want lightweight and compact, with decent image quality.

It is only if you f/4 lenses on APS-C are enough for you.

If you need f/2,8 zooms (for speed and DOF), then, FF with f/4 zoom ends up being similar in term of weight, bulk … and cost.

If you need f/1,4 on APS-C, the f/1,8 on FF are cheaper, lighter, less expensive so you indeed save money.

So the real question is what is "decent image quality" threshold for you.

On my case, I am fine with f/4 zooms and 1,8 primes on FF and it is ending up much cheaper, smaller, lighter than a comparable kit on APS-C.

I think quite a few people, who are new to mirrorless, are going to be in for a shock at how large these Z lenses are going to be.

I think they will be sock how good they are. I think that people do not realize that we are not speaking of Nikon / Canon DSLR version of 50mm f/1,8 but closer to OTUS quality.

The Z hype and marketing promise compact, fast primes - but in Nikon's 3 year roadmap, you don't see any fast primes. Why?\

I think they are right. I complained indeed about Nikon not planning the f/4 versions of the 14-24 or 70-200. I think that people will realize that you have primes which are already at the top in term of performance wide open and will make for a very high quality, light and compact kit.

For instance, the Canon 85L was fast but honestly, its quality at f/1,2-1,4 was severely lacking. It is soft. And the transmission is quite poor where I gain just 1/3 of a stop going from 1,8 to 1,2. So anyway, I had to stop down to 1,6 or 1,8 to get good sharpness, enough DOF and because there was almost no light deficit.

Now, with the Sony FE 85mm (which is as good as Zeiss Batis version from my father), I have even better quality than the Canon at 1,8 and I have the stabilization (of the sensor).