Z mount advantage over F mount: wide angle only?

In theory, a wider mirrorless mount with shorter flange distance allows more flexibility in designing high performance wides and ultra-fast-aperture "bragging rights" lenses like 50mm f/1.0 and 85mm f/1.2, but doesn't (yet) significantly affect the design of longer teles. The motivation for Canon and Nikon to engineer new mirrorless-mount teles is almost entirely down to the mismatch of autoficus technologies when DSLR teles are adapted to mirrorless. Offering the mirrorless body equivalent of the sports-oriented Nikon D6 or Canon 1D requires coordinated mirrorless-optimized AF tech in the tele lenses. Since the sports hot-rod mirrorless is of lower initial marketing priority than enthusiast/architecture/portrait/landscape, the long teles were delayed to coincide with introduction of those longer-development, action-oriented bodies.

I said "in theory" above because a surprising number of excellent mirrorless prime lenses (standard and wide) don't rely on the shorter flange distance and/or wider mount to quite the dramatic degree we expected from the technical/marketing lore. Perhaps current sensor tech with its microlenses somewhat inhibits the short flange distance advantage for now, but the new mirrorless mounts will be ready to pounce should sensors evolve to unleash them. Nikon and Canon seem to exploit the new mount more in their zooms and "statement" lenses, while some of the suddenly "wow" new mirrorless primes trace their performance increase less to the mount specs than company motivation to offer killer lenses (at commensurately higher prices) that justify migration to mirrorless.

In theory, a wider mirrorless mount with shorter flange distance allows more flexibility in designing high performance wides

Strangely, Sony with its narrow-throat E-mount doesn't seem to inhibit the release of optically excellent lenses. Makes me wonder if Nikon's Z-mount really had to be that big and whether at least some of the lenses as a result are larger than necessary. On the other hand, Nikon's 14-30/4S and 14-24/2.8S appear to be lenses that could not have been done for the F-mount and possibly can't be done for Sony E-mount either.

while many of the suddenly "wow" new mirrorless primes trace their performance increase less to the mount specs than company motivation to offer killer lenses (at commensurately higher prices) that justify migration to mirrorless.

I believe Sigma has demonstrated that higher performing lenses are also possible for the F-mount (looking at the 40/1.4 Art as one example) but that the resulting lenses are excessively large and heavy. And it appears that somewhat smaller and lighter lenses are possible for the wide-throat Z-mount - though none of the lenses currently available can claim to be compact. The popular 14-24/24-70/70-200 f/2.8 set was already fairly expensive in its latest F-mount manifestation; the current Z-mount trio ups the prices once again.

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Nikon did the reverse for the Speed Magny polaroid back to enlarge the image to make 3.25x4.25" polaroid print but loses 5 stops of light.

When I heard about these Polaroid backs 50 or so years ago, I wondered how they worked.

I figured it had to be something like that, but I never saw it written until now.

A speed booster is intended to mount an FX lens on a DX or m4/3 body; not sure what happens when you mount one on an FX body (shouldn't work since you generally need to mount a lens with a larger backspacing on a camera with a smaller one, so perhaps that Nikon 300mm works on a Leica M or any of the mirrorless bodies? I don't have s speed booster, so I can't try.). With a 1.5x crop-factor APS-C camera, your 300mm with a 0.71x speed booster becomes a "213mm" lens - which is then cropped to a 320mm FX-equivalent FOV; maximum aperture is indeed f/2.

 

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I figured out some time ago, that you should be able to use a DX lens with a telextender on an FX body, as it only takes the center part out of an FX lens.

I never tried it, though.

At least Nikon doesn't stop you from mounting DX lenses on FX bodies, like Canon does.

In theory, I don't know about in practice, you can use a speedbooster and telextender, and get the original lens back again!

the resulting lenses are excessively large and heavy

I guess it depends on what type of photography you're into. Sure, as a landscape shooter you don't want to be lugging a bag full of Sigma fast primes with you up a mountain....;)

I quite like the 40mm as a walkround lens along with the 200-500mm. I know there's a HUGE gap between 40mm and 200mm, but as long as it's sharp (and it will be, bitingly so) I can crop big with a nice D850 RAW file. If a wider scene presents itself, I make a pano or 2.

In a fixed or studio setting there's just no issue and IQ wins out over weight/bulk every time for me. YMMV...:)

Having said all that, sometimes I wish Sigma had made a tripod foot for the 40mm simply to take the strain off the lens/body mount for tripod use.....;) (aftermarket are available!)

Strangely, Sony with its narrow-throat E-mount doesn't seem to inhibit the release of optically excellent lenses. Makes me wonder if Nikon's Z-mount really had to be that big and whether at least some of the lenses as a result are larger than necessary. On the other hand, Nikon's 14-30/4S and 14-24/2.8S appear to be lenses that could not have been done for the F-mount and possibly can't be done for Sony E-mount either.

As I have mentioned before, back in December, I had a WebEx session with a Nikon rep. He pointed out that the Z-mount 14-24mm/f2.8 S is a full pound lighter than the F-mount 14-24mm/f2.8 AF-S, and the Z version's front element is fairly flat so that one can mount a 100mm rectangular filter on it via a bracket or use a round, conventional 112mm front filter on the first stage of the lens hood. In comparison, the F-mount version has a seriously bulging front element. The 14-30mm/f4 is even more convenient, as it just takes a regular 82mm front filter.

In comparison, Sony's 12-24mm/f2.8 has a construction more like the F-mount 14-24mm/f2.8, also with a bulging front element and costs $3000. While the Sony does go even wider to 12mm, personally I think 14mm is wider than what I need. Since I got the 14-30 S, I do like to use 14mm once in a while, but for most landscape situations, 18mm, 20mm is probably as wide as I need. Architecture photography, especially indoors in tight quarters, may be able to take advantage of a really wide lens.

The popular 14-24/24-70/70-200 f/2.8 set was already fairly expensive in its latest F-mount manifestation; the current Z-mount trio ups the prices once again.

The F-mount lenses seem cheaper because they have gone out of favor and are deeply discounted now.

• When Nikon announced the 70-200mm/f2.8 E FL AF-S VR in October 2016, it started at $2799.95: Nikon Announces 70-200mm/f2.8 E FL AF-S VR and 19mm/f4 PC-E Lenses
  
• When the Z-mount 70-200mm/f2.8 S was announced a year ago, it was at $2699.95, a full $100 cheaper than the F version: Nikon Announces D780, 120-300mm/f2.8 F Mount, and 70-200mm/f2.8 Z Mount
  

The Z lenses are simply too new to see a lot of discount at this point, especially since Covid is seriously affecting supply at the moment. Yet, in November 2019, I managed to get the 24-70mm/f2.8 S at $300 off.

In a fixed or studio setting there's just no issue and IQ wins out over weight/bulk every time for me. YMMV...

It does - no studio work here. I was tempted to get the 40/1.4 recently when it was offered as a substantial discount - but aside from the off-putting weight, the more important reason for me to abstain was that I don't know where I am going with my camera setup; the lens would satisfy a want but there really is no need for me to own it. Of all the photographic purchases I may want to do, buying an F-mount lens nowadays is quite low on the list. I am quite certain that the Voigtlander Apo-Lanthar 50/2 is in the same optical performance category as the Sigma 40/1.4 (it also costs about the same). Not really a fair comparison, as it is manual focus and f/2 vs f/1.4 - but on a A7R3 or A7R4, it makes a compact and light-weight combo (about the same weight as the 40/1.4 alone).

Sony's 12-24mm/f2.8 has a construction more like the F-mount 14-24mm/f2.8

Sony also has an excellent 12-24/4G lens - a lot lighter than Sigma's 12-24/4 for F-mount. But unlike the Nikon 14-30/4S, it still has the bulging front element.

you should be able to use a DX lens with a telextender on an FX body

Anyone know of an FX > DX 'concentrator' ? I guess it would need to narrow the beam, but keep the same back focus.

I quite like the sound of a 213mm f2 for my FX 300mm 2.8 on my DX D500...:cool:

Anyone know of an FX > DX 'concentrator' ? I guess it would need to narrow the beam, but keep the same back focus.

 

I quite like the sound of a 213mm f2 for my FX 300mm 2.8 on my DX D500...:cool:

As far as I know, there is no rule against it. As with the speedbooster, it just cancels out the crop factor.

You put your 300mm FX lens on, which makes it a 200mm DX lens, which gives the 300mm field of view.

Someone just has to decide to make one. And also come up with a good name for it.

Do the Z sensors use microlenses? I'd assume that bringing light into the sensors perpendicular to the surface would be desirable. Given the electrical contacts, you need a big mount to accommodate the big rear element needed to do that. Armchair speculation anyway.

AFAIK, all current sensors designed for normal photography employ microlenses. Along with sometimes overly-thick cover glasses, microlenses interact badly with "true" (symmetrical) wide angle prime lens designs that sit close to the image plane. This has proved very taxing to medium format digital photographers, who relied heavily on such lenses for movements and perspective control, and some classic dedicated wide cameras like the Hasselblad SWC 38mm Biogon. In the heyday of Kodak and Dalsa-mfd CCD medium format sensors, the lack of microlenses constrained high ISO and other specs but did allow reasonable use of symmetrical wide angles and movements.

After Sony devoured the entire sensor industry, introducing scaled-up 50MP CMOS with microlenses thru Phase One etc, digital medium format photographers were confronted with the same corner and color cast issues that plague Sony A7 users who hoped to mount their compact Leica rangefinder wide angles. Curing this interaction requires a custom sensor fab (and imaging engine) optimized for symmetrical lens use, which Leica has done to keep the digital M camera and M lenses viable. Unfortunately for photographers desiring smaller less-expensive non-Leica gear, general-purpose mirrorless mfrs like Sony, Nikon and Canon have no incentive to do this, as their market vastly prefers zooms over compact primes. Even the specialist medium format market was forced toward more retrofocal wides, as custom Leica-style MF sensors would be cost-prohibitive.

So the huge diameter, very short flange Nikon Z mount currently isn't used as much to facilitate smaller or higher performing wide angle primes: Nikon exploits it more to design collapsible zooms and/or high performance wide zooms without huge bulbous front elements (impossible or impractical with F mount diameter and mirror box clearance).

Just curious. Is the wider throat of the Z mount particularly advantageous for wide angle lenses?

This OP's question appears to have been hardly addressed at all so far.

My thoughts on this are: That the sensor's requirement (and yes, they are covered in microlenses) for a degree of telecentricity outweighs the short register, and therefore there's little advantage in terms of wideangle lens design freedom.

It's been known for some time that non-retrofocus wideangle designs - such as those made for Leica film bodies - do not perform well on mirrorless digital cameras.

We have to look at what exactly makes a lens 'telecentric' to understand the reason. A fully telecentric design would have its projection precisely perpendicular to the image plane. In other words the image would be projected as a parallel beam of light originating at a virtual infinitely distant point. This, if you analyse it, requires a rear element of large enough diameter to cover the image circle; making such a lens large, heavy and expensive, regardless of its numerical aperture.

A digression. The only design I know of that comes close to true telecentricity is the original Ernemann Ernostar lens, as fitted to the famed Ermanox camera. A camera whose body is almost totally obscured by the large chunk of glass fitted to it.

Back to the subject in hand.

Telecentricity allows the microlens array of a sensor to work efficiently, by keeping the image rays perpendicular to the sensor everywhere across its surface. This is at odds with a short back-focus and proximity to the sensor; unless an additional rear group of elements is added to a wideangle design - making it effectively retrofocus and adding to its weight, size and complexity. In which case you might as well have started with a requirement for a long backfocus in the first place. As is needed to accomodate the mirror of an SLR.

I know about microlenses for the Lytro, but hadn't thought about them for others.

The Lytro has a microlens in front of some number of sensor elements, which allows

it to capture the direction of the incoming ray. It does complicate figuring out the

actual resolution, though.

The original Lytro, which I have one of (bought for a low price sometime after it came out),

seems to have an 11 megaray sensor. That is, 11 million sensor elements, I believe in

4x4 arrays under each lens, so about 0.7 million microlenses. Since the sensors within

a 4x4 array contribute some to the final resolution, the best estimate is the number

of microlenses times the square root of the sensors per lens, or about 2.8 megapixels.

To be able to use the ability to sense the ray direction, the lens stays at f/2,

though has the ability to zoom.

The only thing I remember about the image processing is that the first

step is a 4D Fourier transform. The main advantage claimed is the ability

to refocus after the picture is taken. It is also supposed to be possible to

get stereo pairs out, but I didn't figure out how to do that.

Simple explanation of microlenses.

Nothing to do with light-field camera macro lens arrays.

No-one brave enough to remove the CFA and Microlens Array from a MF sensor?

Results in a B/W sensor that's good for UWA lenses......:cool:

Interesting review with techie measurements.

Nikon Nikkor Z 14-30 mm f/4 S review - Distortion - LensTip.com

Seems they are relying on digital correction post capture to sort out some massive optical issues.

Seems they are relying on digital correction post capture to sort out some massive optical issues.

Quite common these days I'm afraid. Why would anyone care where the very good optical performance comes from and how it is achieved? Isn't the result what counts? With film, there was no other chance than to correct for distortion in the lens directly; nowadays, there is - so why not use that opportunity? Of course, mount such a lens on a camera body that doesn't apply those corrections, and things get a tad difficult. I doubt that the post-processing corrections that some software can apply is as good as what the manufacturer included in-camera.

Quite common these days I'm afraid. Why would anyone care where the very good optical performance comes from and how it is achieved? Isn't the result what counts? With film, there was no other chance than to correct for distortion in the lens directly; nowadays, there is - so why not use that opportunity? Of course, mount such a lens on a camera body that doesn't apply those corrections, and things get a tad difficult. I doubt that the post-processing corrections that some software can apply is as good as what the manufacturer included in-camera.

If issues such as distortion can fairly easily be corrected in software/firmware, either in camera or in post processing, wouldn't it be much simpler and economical to do that than creating a much bulkier, more expensive lens with better optical characteristics? The huge advantage for the 14-30mm/f4 S is that it is quite affordable; I paid $1100 for mine, including sale tax. It is also quite compact and can take conventional 82mm filters.

I understand plenty of Micro 4/3 wide lenses also depend on software to correct distortion.

I wasn't necessarily saying it was a bad thing........:p

I guess vignetting was one of the earliest in-camera corrections via menu choice.

I wasn't necessarily saying it was a bad thing........:p

 

I guess vignetting was one of the earliest in-camera corrections via menu choice.

Ironic really, because I often add a little in post. Guess it goes both ways? :)

Sort of already does with Z lenses, the corrections are baked in

Oooo! You mean it can't be switched off?

This review..

Nikon Nikkor Z 14-30 mm f/4 S review - Distortion - LensTip.com

measured the distortion without any correction by using a 'dumb' RAW converter.