#996. That Sony curved sensor. Great news?

By pascaljappy | Opinion

Apr 29

Five years ago, I would have begged to have such a sensor in my camera. How about today ?

Delightful news

Several readers have sent me the news about the new thechnology. Curved sensors, at last, seem to be ready to take a giant leap from the realm of tiny dimensions into the hairy-chested kingdom of digital medium format.

As a life-time lover of optics (I built telescopes as a hobby as a teen and would have studied in a French engineering school called SupOptic, had my grades been significantly less subpar), the news should really excite me. And, on an intellectual level, it does.

A spherical lens, by its very nature, wants to focus on a curved surface. It takes a lot of design effort to actually make it focus on the plane surface that is a film or a sensor. This effort entails an optical formula that employs numerous optical elements and, now that technology allows it, aspherical designs.

Uh oh!

So, in theory, using a curved sensor will yield the following end user benefits :

  • Faster lenses. Just like chromatic aberration, field curvature is cured by closing down. With a curved field, there’s no need to. We can now imagine an f/1 lens that will be almost as sharp wide open, over the whole field, as at f/8.
  • Lighter lenses. Because all of the optical train used to flatten the image will not be necessary, 12 element lenses could become 8 element lenses, or less.
  • For the same reasons, we can expect cheaper lenses. This could make medium format accessible to a much wider range of users.
  • And because there should be no need for aspherics, two extra benefits arise : one is better quality control. Since a sphere is a sphere is a sphere whatever way you turn it, alignment tolerances for spherical lenses are much easier to achieve than when your design contains extreme aspherics.
  • And also, as the Milvus 85 abundantly proves, the look from all spherical designs is easier to make gorgeous.

As you can see, the concept is fantastic and exciting! Kudos Sony.

Shine a light

You’re expecting a … but! Here is comes. Or, rather, here they come πŸ˜‰

The first one is slightly unusual, for Sony. But, could this be a little too late? Digital medium format is now a mature game, with well established players and heavily invested users. It’s gonna take a lot of IQ to make me take a big hit on my 5-lens Hasseblad setup, for example (and something tells me, I’m one of the less heavily invested MF users out there … ).

Not once, since the X1D has been with me have I thought “hmm, I wish this thing had better IQ. I wish the sharpness was better, or the colours were prettier, or the corners were this and that”. Hassy has refined its offering to a point where seeing much better IQ anywhere feels a little bit like science fiction, to be honest.

So, does this leave people using high-end full frame cameras and wanting to trade up, as the only candidates? I would have thought that most who want to and can already have. And, if they haven’t, how is an unproven system with few lenses from a manufacturer with no presence in that market going to change that?


The second but is … well … Sony.

Calm down, maybe you love Sony. I sure did at some point in my life. But everything I’ve been able to read in the way of statements from Sony officials, about this sensor, points to the Sony trait that displeases me most: technicality.

A curved sensor, on top of the numerous aforementioned benefits, presents its corner pixels squarely to the lens, rather than at an angle. That’s great for two things: no smear from legacy lenses (sorry, can’t help being silly), and less vignetting. Which, frankly is nice to have. Particuarly if you then add one of the dozens of specialty lenses that seem to pop up every week with a vintage look and 2 stops of vignetting (oops, sorry).

The other benefit is lower dark current noise. Excellent on paper. In real life, I wonder how many of the 2.4 billion photographs taken since I started writing this post, actually suffer from excessive dark current noise? Just asking. More seriously, Sony have become masters of the technical aspect of photography. Power to them. But I find the argument less and less compelling, given where the market has arrived today.

The nightwatch

The third but is an elephant in the room. Maybe it’s too early to judge but the initial list of lens patents starts at an equivalent focal length of 52mm. What’s that about? I see two options (let me know if you know more about this)

Option 1: Giv’em some time, already. Yup, sure. Sorry. Personally, I’d have sold the curved sensor with a 28-40 Tri-Elmar type fixed lens, so who am I to complain? It just seems a little odd to start at the long end of the range, where field curvature is much less of a problem …

Option 2: It’s not that easy to start afresh on a wide angle design that doesn’t match the sensor’s curvature. Of course, Sony’s engineers being as talented as they are, will produce excellent wide angle lenses for the system. But maybe a slightly curved sensor doesn’t make that big a difference in wide lens design compared to a flat one. We’d be back at square one: too little too late?

Trees and forests

Maybe I’m not being fair to Sony. The curved sensor is a great engineering achievement and, 18 months ago, it would probably have been ebough for me to hold my horses and not jump to Hassy before evaluating the final product.

Still, though.

When Mandler was head of design at Leica, the characteristic wave in the lens MTFs showed how difficult field curvature was to correct. A few years ago, the harshness of most well corrected lenses outside the Zeiss stable, showed how difficult it was to do so at an affordable price and with decent rendering. Now, though … If you want affordable excellence in a Sony package, the GM lenses and the Milvus range give it to you in spades.


What this new camera could bring to the market is Sony’s typical high speed capabilities. As meaningless as this is to me, I understand it speaks volumes to others.

And, let’s face it, this is Sony. So the camera will over-deliver. Over the last few A7x releases, Sony have repeatedly improved both hard skills and soft skills in leaps and bounds. And their strategic department has proved over and over again how well it can read and dominate this crumbling market. In the end, the camera could even overshadow the tiny incumbents in the medium format corner of it.

So, it’s all about bringing more pixels, more ISO and higher MTF to an arena that’s already suffoctaing from its overly technical biases, well, meh … as far as I’m concerned.

However, if this highly symbolic sphere signals the organic reboot the industry so desperately needs (it certainly has all the ingredients for that), then I sincerely wish Sony the very best of success !!

Humble bumble

We shall see and I will be watching keen eyes. Who here might consider this as their next camera? Who’s excited? Who thinks it’s just another tech trick? Who thinks it’s a revolution? Who’s having a curved ball?

Completely unrelated but … final call for Bayhem Challenge !!


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  • philberphoto says:

    Ah, why is it that I smile when I write that I respectfully beg to differ with the learned Wrinkly Senior [(c) SJ]?
    A curved sensor means all-new lenses. Why on earth would Sony, a for-profits business, offer a new product that sets such a high barrier to entry? Especially Sony, who are now the company whose mirrorless camera has by far the strongest set of native lenses. Because they believe it has merit. But this is like a criminal investigation. Find a motive, follow the money. Cui bono? The answer is simple and straightforward. Sony bono (no, not Sonny Bono). So, in order for it to become really bono for Sony, Sony needs to make it bono for Philippe. Life is simple until people weave complexity into it.

  • jean pierre (pete) guaron says:

    Sigh – I don’t even understand it – I’m a camera user, not a lens designer.
    Still – I’ll try to say something sensible for a change.
    1 – how nice – but it’s way too late for me, now – I’ve repeatedly said, I’ve MADE my choices and I am going to have to ride out the rest of my life using the cameras and lenses that I already have
    2 – in line with your query, as to how this can better your Hassy – for my purposes, the quality of the images produced by my current cameras is past the point of perfection that I need – since I print my photos on an ink jet Epson printer, and 45MP is a blast – sometimes I deliberately soften the focus because it’s simply TOO sharp – so whatever anyone else is going to get from this, I can’t really see any advantage in it for me
    3 – this is technical advance – hurrah! – in a collapsed market, too, and trying to jump into a niche end of the market – best of luck with that one, Sony
    4 – but actually I’m all in favour of technical advances – with one proviso – I want ALL the manufacturers in the market to give serious thought to industry standards, so I can put a Canon lens or a Sony lens or a Leica lens or a Nikon lens or anything else, on the front of my camera – so that we stop arguing over the size of the hole the lens goes into – so that I’m allowed to buy a still camera with limited scope for “bursts”, instead of being expected to buy an 8K video camera disguised as a DSLR
    – I get the idea of the new Canon & Nikon mirrorless cameras, the big hole for the lens, the fact the rear end of the lens gets closer to the sensor, everything’s new and wonderful – but why the hell can’t I use ANY manufacturer’s lenses on them, without needing an adapter, which simply destroys the whole point of the new lens mount design, taking you right back to where photographers like me are, right now?
    Sorry champ – I’m voting with Pascal – he knows more than I do anyway. “Improve” means more than simply being “different” – you have to be “better”, as well – and “better” on only one measure ain’t gonna get you there!

  • Jean-Claude Louis says:

    In my view it’s not a revolution, far from it. It’s an interesting improvement of a technology that, frankly, shows its limits and is reaching its endpoint. I’m not even sure that the image quality will be noticeably better than what can be achieved with the best-in-class options available now.
    What I would like to see are new concepts, new ideas, real innovation. The research exists, the talent is there, but, unfortunately, the current market will not support it.

    • pascaljappy says:

      I couldn’t agree more, Jean-Claude. As you know only too well, it’s difficult for young spouts to survive when they are ahead of their time (L16 hint, here) but I too hope more will try. Eventually, someone will change this ageing sector for the better. What baffles me is that digital should have opened up incredible oppotunities and hasn’t. It’s made us less weary of trying out things, because the click cost is negligeable. It’s allowed for faster feedback. But it hasn’t exploited its creative potential. Hopefully, that will change!

  • Kristian Wannebo says:

    I believe this is a manufacturer’s aid with marginal influence on photography – perhaps we’ll get handier or cheaper tools, especially for (extreme) wide angle photography.

    Consider as an example the SLR, technically complex and needing very high precision manufacturing. But it solved the problem of WYSIWYG – for seeing DOF in larger formats and for lens change. (My grandfather had a fixed lens 20x20x10 cm sized glass plate camera that folded out to an SLR.)
    And now camera manufacturing can shelve this thanks to good enough EVFs, thus simplifying and saving. And they don’t seem to mind developing new lenses taking advantage of new mounts instead of remounting previous designs.

    Now to the curved sensor.
    It would certainly allow simpler and cheaper (or faster) lenses on fixed lens cameras, or allow them to be more pocketable. (Including phone cameras and so called action cameras.)

    And for ILCs?
    Not knowing optics, I’d guess that the ideal sensor curvature would depend on the viewing angle of the lens?
    ( Or is there a middle way for a longer range of focal lengths?)
    Perhaps a renaissance for the Ricoh GXR concept?
    ( A camera with interchangeable lens+sensor modules.)
    Or would we first get an additional curved sensor camera body for photographers wanting the wide angle lenses then possible?
    – – –

    > “.. a little too late?”
    Sooner, or probably later, diffractive optics will enter the camera world as nano technology gets cheaper and optical research finds lens designs and combinations. What sensor surfaces would that need?

    • pascaljappy says:

      Hi Kristian, you are right the Ricoh GXR idea is excellent !
      Diffractive optics? I honestly don’t know how they work. But if the index changes throughout the lens, it’s probably to replace combinations of simpler elements. My uneducated guess would be that a curved sensor would render them pointless?

      • Kristian Wannebo says:

        Pascal, I’ve no idea about that.
        But I’ve read that diffractive lenses could be made much more compact.
        [ Canon makes a tele zoom with a diffractive element that is much shorter than its sibling (both 70-300mm 4-5.6).]
        And I _imagine_ that diffractive lenses – in principle – could be designed with properties rather different from those of optical lenses.
        There seem to be many experiments going on with different patterns of nano structures on “lens” surfaces.

      • jean pierre (pete) guaron says:

        Pascal, I’m still confused. Kristian seemed to suggest that the curved sensor will win in round one, with a fixed focal length lens – but seemed to go on to ask if this still holds good, if you drop from a 50mm to a 20mm w/angle, or go in the opposite direction and use it with a 500mm extreme telephoto.
        Is the answer that these lenses will be redesigned to match the curve on the sensor? – just as they are at the moment, designed to hit a flat sensor?
        Or will there be some fall off, as the focal length shortens or lengthens?
        I must admit, I admire their courage – being the only player on the field, playing this game, must come at one hell of a cost!

        • pascaljappy says:

          Well it could just be marketing bluff, or there could be really great benefits I can’t foresee. Who knows?

          As for lenses. In theory(!) one focal length will fit one curvature. The more you depart from that, the less benefits there are to the curved sensor. So, if the sensor is “optimal” for a 100mm lens, then the benefits at 30mm are much slighter. But they are still there, better than nothing! There’s a whole range of focal lengths around the “optimal” that will strongly benefit. The fact that the first lens patents are mostly long lenses could indicate that’s where the current sweet spot it. But maybe Sony are just putting us off the scent? Who knows? πŸ™‚

          • jean pierre (pete) guaron says:

            Thnx – I kind of suspected something like that, but don’t have your technical knowledge.
            A related issue is a special head, for doing panoramas – putting the”axis” around which the lens/camera body swings, as you go from one side of the subject landscape to the other, somewhere in front of the sensor, but behind the front of the lens. The theory is this makes the panorama sharper – by continuously throwing the sharpest focal point of the rays of light reaching the sensor from the view in front of the lens, onto – instead of behind or in front of – the sensor.
            I hope that makes sense to you – with your technical knowledge, you’d probably have a better way of explaining it.
            I have so far rejected these overtures. As I swing the front of the lens across the field of view, I have more than enough issues with the fact that the landscape I’m photographing is not on a flat plane – it comes closer to or recedes from the camera all the way across the field of the panorama, making it desirable to reset focus for each successive shot. And because I’m doing this in live view, I feel like having a black cloth over my head & the camera, because backlighting one of these screens on the back of these cameras is not exactly ideal when trying to focus the lens. πŸ™‚

  • Frank Field says:

    I’m so heavily invested in Nikon that switching is all but unimaginable to me. Still, there are potential attributes here that have appeal. If indeed a curved sensor leads to smaller and lighter lenses, that would be most welcomed. I much dislike the trend over the last 10 – 15 years of bigger and bigger and heavier lenses. Gosh, putting a 24-70mm f/2.8 (from any manufacturer) on your camera is like dragging a bazooka around. Not something you want to do all day long. Even primes have become bigger and heavier, almost no matter where you look. Second, if a curved sensor does indeed lead to reduced complexity (fewer glass elements) lenses, that would be most welcomed. Like many, I believe that today’s 12, 15, 19 element lenses lead to absolutely sterile images in comparison to the much less complex lens design of the final years of the film era. Improved micro-contrast is just one benefit of fewer glass elements.

    • pascaljappy says:

      I agree, Frank. And to me, the prospect of having lenses that meet the modern standard of aberration-freak-out without being as sterile, is the single largest benefit of a curved sensor. I would love to see 4-element lenses resurface!

  • Jeff Kott says:

    My understanding is that curved sensors will allow for much smaller lenses, so that would be another factor in the plus column for me as I’m always looking for the best IQ in the most compact kit.

  • Patrick says:

    Very educational and inspiring lines on the battle for technical hardware advancement. My simple and humble view is to focus, always, on bringing about the message (of the photographer) via the end product i.e. the photographs. After all, top photo gears is no guarantee for producing top photos. However, it is interesting to know how the battle is progressing. Thanks for sharing, Pascal !…and, do keep up the traffic.

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