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Is the Sony E-mount Already Becoming Obsolete?

Mirrorless… the one design to rule them all. The master of the full frame is undoubtedly Sony, however has it inadvertently introduced a short-lived shelf life with some in-built obsolescence?

Sony's Slow Burn

Sony, that behemoth of consumer manufacturers who brought us iconic designs such as the Walkman, have a strange camera heritage which includes the 1981 Mavica, the first digital stills video camera. For a company so wedded to consumers, it had long championed video cameras (anyone remember the Betamovie BMC-100P?) but was strangely silent (barring the Mavica range) when it came to stills. It wasn't until it acquired Minolta in 2006 that it's stills camera division was truly born. Minolta manufactured both cameras and lenses and was arguably at the technical leading edge from the 1970s onwards. In this sense they were a good match for Sony, although were late to the digital party, releasing their first DSLR (Maxxum 5D) in 2005 which used the 1980s A-mount for all its lenses. This is Sony's "standard" DSLR mount and can still be found on a few of its SLT cameras.

Mount Wars

Sony followed the pivot to mirrorless that was led by Olympus and Panasonic in 2008 with their release of the Micro Four Thirds format. It's worth bearing in mind that this was an exciting time for mirrorless development and the requirement for new lens mounts. Sony released their first mirrorless camera in 2010 (NEX-3; APS-C), along with Nikon in 2011 (Nikon 1 V1; CX), Canon in 2012 (EOS M; APS-C), Fuji in 2012 (X-Pro1; APS-C), and Leica in 2014 (Leica T Typ701; FF). It's also worth remember that the Alpha 7 arrived in November 2013.

Has there ever been such a gold rush of lens mount announcements before or since? It makes me wonder about the nature of shifts in the camera industry. Consumer electronics has increasingly seen short iteration cycles of rapid development and product replacement. This is perhaps counter to traditional camera manufacturing, particularly for lenses which are intended for longevity. As a result, the market now operates on the basis of a rapid turnover of camera bodies and this may well be driving revenue. So why was there a sudden move to new mounts? Was the commercial success of Panasonic and Olympus a key reason or did the other manufacturers already have plans in the pipeline? Was it a case of herd mentality, with each manufacturer offering their own vision of what a mirrorless mount should offer? Remember that this was a period of rapid growth and large sales volumes, which almost certainly allowed for generous R&D budgets.

Sony, Nikon, and Canon were all relatively quick to market with new mounts and lens lineups, yet these were clearly consumer products. In particular, Nikon and Canon were clear that they didn't want to cannibalize their professional DSLR sales and that drove their mentality. It wasn't until Fuji's X-series and Sony's Alpha 7 that higher end mirrorless cameras came to market.

Mount Development

There are two primary design parameters for any new mount: mount-to-sensor distance (flange distance) and mount diameter. The flange distance is a result of the thickness of the camera which has to house all mechanical components. Principle among these is the viewfinder: in analogue cameras, manufacturers have used twin lens reflex and rangefinder designs, but settled upon the single-lens reflex. To accommodate the mirrorbox, the camera needed to be relatively thick, making the flange distance large: the Nikon F-mount (below) is 46.5 mm. By going mirrorless with an EVF, Nikon have reduced this to 16 mm with the Z-mount, whilst still incorporating an IBIS sensor.

The mount diameter needs to be at least as large as the sensor so that light can enter parallel to the optical axis. Leica's legendary M-mount is 40 mm which gives 2 mm of leeway on either side (it's also worth noting that the flange distance was a svelte 27.8 mm due to the rangefinder design). Making the mount diameter larger gives two benefits. Firstly, more light can enter the lens meaning, within design constraints, faster lenses can be manufactured. This is measured as the incidence angle, the angular deviation from the optical axis.The larger the value the better, although sensor microlenses become less efficient at extreme angles which can lead to vignetting.

Secondly, large mounts (by definition) result in larger orifices allowing significantly more space for optics, meaning manufacturers have greater latitude in their lens designs. The trade-off of bigger mounts is bigger (and heavier) lenses.

The Future

The combination of a larger mount diameter and shorter flange distance produces the largest incidence angles, but does any of this really matter? Well yes, because in the search for ever more exotic glass, manufacturers ultimately run up against optical physics and the constraints they impose. The flip side is that you can use the in-built advantage of a larger mount with more light, to produce simpler and cheaper lenses.

So how do the different mounts stack up? It's worth reviewing incidence angles for traditional DSLR mounts: the Nikon F is 12.14° (44/46.5 mm; mount diameter/flange distance), whilst the Canon EF is 16.8° (50.6/44 mm). This is one of the reasons why Canon shooters have often had a good lens selection. It also goes to show the constraints that the SLR specification places upon lens design.

So what about the new mounts? Here Nikon makes great play of a 41.2° (52/16 mm) incidence angle, in comparison to Canon's RF at 33.62° (50.6/20 mm). As a comparator, the MFT format runs at 32.5° (38/19.25 mm) which is perhaps what originally made other manufacturers sit up and listen: a significantly smaller body, significantly smaller lenses, yet relatively fast glass (not withstanding the effect of the crop factor).

And what about the other mounts? The Leica L is 33.13° (48.8/19 mm) and Fuji X is 35.3° (40.7/17.7 mm). Which brings us back to Sony, the first to the punch with a full frame mirrorless mount which has an incidence angle of 28.6° (43.6/18mm). Except it wasn't designed for full frame mirrorless but its NEX series of APS-C format cameras and camcorders. This raises the question as to the design motivations of Sony when it first developed the E-mount. Was it to terminate the Minolta product line and split their offerings in to an APS-C mirrorless range that could support both stills cameras and camcorders, along with a "professional" A-mount SLT line? If you calculate the incidence angle of the E-mount for an APS-C sensor then it is a much more forward looking 37.9°.

So did Sony intend to produce a full frame mirrorless camera or was it a result of the success of its NEX range and some Sony labs product experimentation? Was there always a plan to disrupt the DSLR market with mirrorless or did they fortuitously expand at a time of DSLR decline? Certainly, pursuing the mirrorless full frame format when camera sales were so high seems a risky strategy in comparison to Nikon and Canon, yet the inroads they have made in to the market have subsequently been significant.

Of course the performance of the E mount is still significantly better than comparable DSLRs and back in 2013 gave them the flexibility to produce competitive quality lenses. However that advantage has now flipped back to Canon and Nikon (and to a certain extent the L-Mount Alliance) with the release of the RF and Z mounts which are designed from the ground up for full frame mirrorless, with Nikon arguably the most aggressive in its pursuit of competitive advantage. Canon is also no stranger to mount development: over the period of Nikon's F-mount, they have had the R, FL, FD, and EF mounts which didn't seem to hinder the success of the brand.

Has Nikon built a lens mount that provides users with the option of exotic glass (such as the 58 mm f/0.95 Noct), whilst giving the flexibility for a wide range of affordable lens designs from third party suppliers? Or has it encumbered itself with another great design that will simply be superseded by another manufacturer in a few years time? Has Sony shot itself in the foot by sticking with the E mount and relinquishing the mirrorless advantage it once had? The willingness of photographers to change brands suggest the "stickiness" of remaining with one manufacturer may be short lived. Or will we see Sony, and then Canon, iterate over mount designs to constantly improve their optical offerings?

Do you think Sony should change mounts?

Lead image courtesy Rainer Knäpper (Free Art License) via Wikimedia. Body image courtesy of emdx and Nebrot via Wikimedia. All used under Creative Commons.

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Previous comments
Steven Dente's picture

If images start being made with the new Nikon, and Canon mirrorless mounts that could not have been made with the Sony E mount, then it might become an issue. Otherwise it won't matter much which mount you use.

sam dasso's picture

SONY has about 30 FF E-mount lenses already. Why would they switch mount? Why would anybody who has FF Sony mirrorless body want them to do that?

Black Rock's picture

I think there are 61 Sony Full Frame E mount lens as of now.

37 APS-C lens.

Gary Pardy's picture

You lost me at your third "whilst"

Jerome Brill's picture

I'm only saying no because I'm close to filling in my lens lineup and I don't want to have to buy new lenses. Could Sony have made their mount better with more research? Sure but mirrorless was still relatively new. I think they did a good job and in the future they'll probably employ other tech to mitigate it. These mounts are not going to make or break any of these camera manutatures. Although the first company that starts doing what cell phones can do but with raw is going to be the one that comes out on top.

Silvestro Crino's picture

I’m still trying to figure out what wrong with their mount...with it they And partners have created over 60 FF lenses and nearly 40 aps-c lenses ...interchangeable on all their bodies ...the best AF in the industry with the A6500, A9, A9II and A7r4...also, emount hasn’t kept them from putting 5 axis IBIS on nearly every body... what needs to be better?

A P's picture

Everytime I read an FStoppers article, I regret wasting my time. They're just as bad as a tabloid and are now forever removed from my news feed.

S. Spencer's picture

There are no real world issues.... Nope. Even the behemoth… ultra bright Sigma 35mm 1.2 it's beautifully sharp in the corners for the e-mount. I'm not even sure what Canon is doing.... Great New glass..... So heavy.... But for mirrorless? Huh?

Pretty sure there wouldn't be any real world difference if those same lenses we're available on an e-mount..... Technically..... Scientifically..... In the minutiae...a wider mount would be very slightly better. Real world? Nope

akira h's picture

I read somewhere interview with canon's engeneer, in that interview he mentioned RF's bigger mount size is more consideration on durability, not much for optical design.(bigger mount doesn't bring much difference for optical design, he mentioned)
Personally I think, for optic, sony's FE is fine enough, but IBIS, etc could limited with it. At least macro tube has already limitation with small mount dia.
Let's see. time will tll us. Unfortunately there are no ultimate golden mount size. everything seems trade off.

Jonathan Brady's picture

2018 is rolling it's eyes at this topic that was beaten to death back then.

Paul Chambre's picture

A few incorrect assumptions above. One: Sony was not silent on stills (besides Mavica) before acquiring Minolta. They had several interesting stills cameras on their own, with the DSC-R1 ("Highly Recommended" by DPReview) probably being the most impressive. Two: no, the mount does not need to at least as large as the sensor/film. The Deckel mount, for instance, that was used in many Voigtlander and Kodak SLRs, is 38mm in diameter, while a full frame is just over 43mm. That Nikon F mount in the article has a diameter of 44mm, while E mount is 46mm.

Rk K's picture

Every single practical evidence contradicts your bs theories... Why is this blatantly wrong, misleading article allowed to remain here?

Jonathan Ferland-Valois's picture

E-mount has a bunch of great lenses, many of which I slowly acquired over the years. I think that changing mounts would just be a pain in the ass for both photographers and for Sony, as they'd be again in that position where they have a new mount without the lens variety, and photographers would have to buy into a new ecosystem again. That's crazy, and the little benefit we'd get from it are absolutely not worth the trouble.

Mark Ferencz's picture

Nikon is going under, Sony is obsolete. This is the type of click bait that makes Fstoppers the National Inquirer of photo web pages. Desperation to get you to click and acknowledge to pump numbers for ad sales is just business, but choosing to find other places to read photo news is my business too.

Daniel Ardeline's picture

If you haven't got something nice to say, don't say anything at all. Had you read any of Mr. Smith's other articles? This one had at least presented technical details for people to ponder.

There's no shortage of opinionated, and to me, "National Enquirer" like posts talking about how, "Well, this article is bogus, and the product, because those in the know can see that 'xyz' brand is about to go bankrupt, anyway". There ARE people who are interested in the subject matter. How can you be so sure that this article was solely an ad traffic generator? They are no different from a number of other sites.

I can find videos and articles from so-called experts about how just about any brand "just won't last".





Peter Blaise's picture

I cannot follow the random measurement and meaning of your degrees - please edit and illuminate better, so to speak.

If you are suggesting that the rear lens element should be allowed to be the same size as the sensor, in order to allow a lens design that fills all sensor cells equally with parallel light incidence of 90 degrees, is that so hard to say?

And what does "... Sony refactor the ... E-mount ..." even mean?


Dom Oranika's picture

I'm not engineer but, I am an engineering student. Sony's current lenses prove that this need for much a big mount is more marketing than anything. EF mount has 1.2 lenses, but the RF can even bigger 1.2 lenses. Also those values for the angles are only based on a lens with the rear element exactly at the flange, which is not the case for most lenses in E mount.

Paul Fountaine's picture

Sales are down across the board for mirrorless and DSLR cameras. It's a long trend, and it's not improving. Seems like it would be suicide to change lens mounts at this point. And in my view, the advances in image capture will not be in the lens, or the mount, but in the continued advancement of software. Cell phones have shown us that there is far more that can be done with the chips and lenses we currently have on our mirrorless and dslr cameras. A lot more.

Bernard Languillier's picture

It’s hard to say. The late F mount lenses were superior to anything Canon ever released including the 19mm T/S, 28mm f1.4, 105mm f1.4, 70-200mm f2.8,...

So superior engineering can compensate some intrinsic mount limitations.

But it’s true that Nikon S glass is overall superior to the Sony FE lenses but they are also newer and not all lenses are directly comparable. The Nikon 24-70mm f2.8 is clearly superior though, the 70-200mm f2.8 probably also. We’ll have to test actual lenses when it ships.

Comparing the new 20mm f1.8 should be interesting but the Nikon design seems more focused on image quality while Sony is more about compactness.

So mount potential is one aspect but the design priorities also strongly impact.

J Michael's picture

Almost without fail, for any headline you see with a question in it, the answer is, "No."

Richard DuBois's picture

I read these many paragraphs. Has anyone noticed that this article has no news and basically does not say anything worth a read ?

Blake Aghili's picture

Interesting read .... I kind of like that Leica alliance with L mount ... we can get Leica Camera with a more affordable Sigma lens on it .( Pretty much for SL2 )

Gil Jesus Seraspe's picture

No! Shouldn't condem their E-Mount as the are ''future proof'' and are compatible with their Pro Cinema cameras like FS or evenVenice! And recently, their Xperia Pro line of phones are gonna kick the competition out of the water! Smart move for Sony that Canikon/others and their fanboys are making the ''one mount'' solution mess on the net, and are a complete garbage collectors Hurray for Sony for making us believe this is all possible and they know what they're doing! And oh, they're not just a computer/consumer company, they're probably bigger than all those companies combined! That's why i love Sony! Just my 2 cents.

Former user,
Canikon, Fujitax, Panasung.

Patrik László's picture

Say just one thing, only one, what can't be done with a F1.2 or F1.4 lens. I'll wait.

Deleted Account's picture

Shooting at f/0.95.

Silvestro Crino's picture

This article is completely a joke... the Nikon 58mm f.95 is a huge monster and is a manual lens... the Mitakon 50mm f.95 Mark 3 in FE mount is much smaller and lighter and had been out so long it at version 3.... additionally, Sony, Zeiss, Tamron, Sigma all have lenses out for FE mount and Sony’s lens family at all price levels is very high quality and the most complete... able to excellently resolve 42 and 60 megapixel sensors in Sony’s FE exactly has the E mount held back Sony IQ or lens development? The article make statements of opinion as facts which are easily proven wrong by reality.

Pieter Batenburg's picture

That 0,95 is an expensive joke. Try to shoot with MF at F0,95. Good luck with that. The DOF will be as thin as a razorblade.

Bernard Languillier's picture

Well I own a copy of this lens, and it provides a unique look, pretty special.

Can one live without it? Sure, but it's a valuable tool to add to a line up and I am glad to have this unique option.

And yes, image quality is out of this world good and focusing is pretty easy thanks to the excellent EVF of the Z7 and stabilization.

Lawrence Huber's picture

PS, The R, FL and FD are all the exact same mount. Just different features added as technology changed. By your definition there are over 8 different Nikon mounts.
Get your data correct please.

Toma Paunovic's picture

I don't see Sony has any problem with quality of lenses compared to other manufacturers, despite the smallest mount.

On the other hand, it's clearly visible that lenses for Sony are by far smallest and lightest compared to other manufacturers. So far, they are the only manufacturer that honors the promise of mirroless being smaller and lighter than DSLR equivalent. The biggest reason why I bought into Sony system was size/price/quality of Tamron zooms and Samyang primes, and it doubt if lenses like these would be possible for Nikon and Canon.

So in the end, is it worth having bigger mount and bigger/heavier/expensive lenses in order to get theoretical advantage in image quality? To me, it's certainly not worth trading real-life benefits for purely theoretical ones.

Joel Wolski's picture

Or maybe, Canon and Nikon shot themselves in the foot in the APS-c market by making their mounts so large.