Sony A7(R) — Optical Options

Tim Ashley
Tim Ashley

Of all the tempting bones that the News Feed of THEME regularly tosses us, new cameras that offer improved IQ and resolution to users of much loved legacy lenses (and for me that often means Leica M glass) are amongst the most toothsome. Sony has announced just such an item of late in the shape of the A7(R) — and suddenly the photographic community is alight with hope. But will that hope triumph over experience?

I am hugely impressed by Sony sensors. I have an RX1 and a D800e and they give the best results I have seen, period. So the idea of seeing such sensors in tiny, interchangeable lens bodies is tempting enough for me to have ordered the “R” variant. But I am aware of the potential fly in the Sony ointment — not enough glass, not soon enough and possibly not good enough (for me).

I recently purchased, tried and about to return the new E mount Sony Zeiss 16-70mm F4 OSS and, assuming that the copy I have is a representative sample, I see it as a warning sign for the A7 series: it seems to me largely to perform like a “kit lens” but at a multiple of the price.

IMHO, Zeiss is ill-advised to let optics of this quality out of the door under their brand name but the fact that they have chosen to do so means they they are willing to, and might do so again. And guess what the key zoom in the new FE range is? A Zeiss 24-70mm F4 OSS* at a price slated to be very similar to that of the E mount lens I found so disappointing above. I will proceed to order one, but with great caution and a firm grip on my sales receipt…

The remainder of the new FE range seems spotty, fairly expensive and with delivery dates for some stretching into next year. So unless you are willing to work with the fairly burly adaptors available for A mount lenses, and the full-frame heft of the lenses themselves, it will likely be a while before you are able to decide whether putting the cart before the horse (buying the camera before the lens lineup is complete, available and reviewed) is a wise move.

Aside from the new FE lens range co-announced with the A7 and A7R, there’s the promise of an adaptor fest: vintage, legacy, loved lenses of almost any marque can be dusted off and mounted on either of the slimline siblings. And for quite a few people, that means M lenses.

Of course, the adaption of M lenses to other cameras has a fraught history: due to flange/sensor distance issues of some historical complexity, M lenses very often give ray angles to the edges and corners of non-M cameras that can mean color and luminance shading and poor edge resolution, even on cropped sensors. The forums are littered with posts from people whose hopes have only been partially met as they gamely bolted M glass onto NEX cameras, Micro Four Thirds cameras, all sorts of cameras. It often just doesn’t work well. Case in point, I tried my treasured M 50 Lux on the EM-1 yesterday and the edges are mush.

To the hopeful photographer it’s always going to be different this time, though. The current narrative is that the new peripherally angled microlens array (on the A7R only: adaptor fiends will need to stick to non-M lenses if they want to use the non-R variant) will be enough to alleviate the problem.

Forum folk are currently gleeful at the prospect of a full-frame camera with 36MP in resolution that not only takes M glass but has a built-in EVF and the luxury of a flexible focus point. And at a fraction of the price of an M Typ 240.

Added to that is news of an app from Sony that appears to offer the possibility of programming in-camera corrections for color and luminance shading and distortion corrections, as well as EXIF lens information. No one yet seems to know how effective it will be or which OS platforms it will work on but my guess is that it will be “JPEG only” for the corrections if not the EXIF and that the corrections will be blunt-ish tools.

In other words, if you are one of the hopeful types anticipating good performance of M glass on the A7R, I say “Don’t believe it until you see it.” It might happen, of course: never say never. But always accept that it has to be a maybe.

Firstly, even the M240, with its bespoke, lens-aware firmware profiles, struggles to deal with the color shading issues, as I have documented in my series of reviews. Note: I have not yet tested the latest firmware to see how much of an improvement it offers in this area but other users report positively. So, bearing in mind that the Sony can’t possibly have in-body lens detection or bespoke RAW pre-processing for specific M lenses, keep your hopes reasonable. Unless of course you want to run Cornerfix on every shot. I don’t.

Secondly, unlike the EM-1, the new Sonys don’t offer any in-body stabilization. Not a deal killer but it would have been nice to use M lenses in that way.

Thirdly, I have proved to my own practical and theoretical satisfaction that the M240 RF is very often a better way of focussing M lenses than is the use of the EVF, magnified, peaked, whatever. The reasons for this are extremely complex and are laid out in my various reviews of the M240 and its lenses on my blog and on the piece on field curvature that I co-wrote with Roger Cicala but I will reproduce a very brief summary for those who don’t want to read much more of my interminable prose…

Nearly all wide and standard focal length lenses have a degree of “field curvature” which means that the plane of good focus is not, as you would hope, a thin or thick (depending on aperture) zone, exactly parallel to the sensor and with its near boundary parallel to its far boundary. Instead, depending on the particular lens, aperture and subject distance, it is generally curved, of varying thickness, and may be wavy in shape too.

Even when wide open but much more so when stopped down, there is more than one distance from the camera at which you can satisfactorily “place” focus if you want the central subject to be sharp. But it is possible to place it such that the edges (and/or other parts of the frame) are not in good focus because they may not fall within the “shape” of the field of good focus.

Thus, when focussing with live view, it is possible to “see” good focus in magnified view, and to activate the “shimmer,” at a range of focus distances. Wide open and close up, that range can be as little as half a centimetre deep. Stopped down and at distance, it might might extend to several metres. Some of those focus distances might get all of the subject plane in focus and some quite possibly will not. But there will always be one exact focus distance that is optimal and, with a well calibrated rangefinder and very accurately machined lens focus cams, the system will find that distance. But with live view, you have little chance of finding that distance unless you always focus wide open and then stop down to shoot — because live view will encourage you to place the central subject in the middle of the field of focus, rather than in the “best” place overall when the rest of the frame is considered.

The only exception to this general rule is that lenses which suffer from notable focus shift as they are stopped down will give better focus on the central subject when focussed using live view if shot when stopped down. Also, certain types of subject pattern (anything with regular repeats) is easier to focus using live view.

In other words, EVF focus is not a universal panacea for focussing M lenses. It is an extremely helpful option, in most cases will be very satisfactory, and on the A7R will be super useful because it will (unlike the M240) offer the ability to select the focus point. Which means that for lenses with significant field curvature such as the 35 Lux FLE, you will have a better ability to focus peripheral subjects accurately. But for planar subjects shot stopped down, IMHO the M240 rangefinder is still the king.

If you do buy the “R” and, on trying it with certain M lenses find that you are getting frames where planar subjects seem to wander in and out of focus there is an easy solution: focus wide open then stop down to shoot.

This may all sound like angels on pinheads but sometimes, to get a shot just right, you have to balance on a pinhead — and knowing how many angels you’ll be sharing it with can really help you work out where to stand…

Then there is the question of adapting other lenses such as those from Canon, which could theoretically work well on both R and non-R variants of the A7. It isn’t yet clear to me what will be available in terms of adaptors but even those that offer full control of aperture and AF seem likely, to me, to feel compromised in size and speed of performance on these tiny bodies. We’ll see. But I am betting that early announcer third party providers such as Samyang/Rokinon will see a spurt of sales in the meantime.

A final thought: I know for a fact that an awful lot of photographers have been waiting for a small high resolution full-frame camera that, in exchange for those benefits, offers a very high quality EVF in place of a mirror and prism assembly. It is a trade off that large numbers of us are clearly willing to make. Sony, ever innovative and ever able to see and fill a niche, looks to have come up trumps.

So what I have to say to CaNikon is this: remember IBM, think about Windows. Laurels can be surprisingly prickly.

* Here is a link to a Sony sample file from the A7R shot with the upcoming 24-70mm F4 OSS at F5.6 though it doesn’t say what focal length was used. The edges look fairly good, the corners less so… but not too bad either.

Sony A7R -- 7,360x4,912 full resolution sample image (click to download) | Sony
Sony A7R — 7,360×4,912 full resolution sample image (click to download) | Sony

Tim Ashley has been taking photographs for over forty years. He loves Leica lenses and bodies, Sony sensors, and more than anything wants someone to re-jig the D800E sensor module, put it in a Leica M with a Fujifilm-like hybrid optical/EVF and make a super high grade, stabilized 24-120mm zoom to go with it. He writes a blog — Tim Ashley Photography — which is dedicated to the twin gods of aesthetic understanding and in-depth equipment reviews, focussing most on the sorts of practical, real-world factors that other reviewers tend to leave out.

He has shot extensively with medium digital over recent years, both Phase One and Leica S system, but is now returning to smaller form factor cameras. Though a self-confessed gear slut, his first love is the photograph itself, and the question of what constitutes art in photography. He is both an avid collector of contemporary photography and maker of his own. His “serious” work is mainly in the area of landscape and conceptual images, which are sold in small, limited editions. He has been published and has exhibited widely.

He lives in England and has more lenses than is good for him.

  • Bengt Nyman

    Thank You Tim and Theme. Excellent !
    To me personally, getting rid of the mirror is a matter of mechanical hygiene, focusing accuracy and noise reduction.
    An experimentally small but optically compromised camera is not on my wish list.
    Long term, the flange distance shall be optimized within the optical events from entry pupil to image sensor. The size of camera and lenses will consequently bare witness of the size of the image sensor, until of course, Daniel perfects his electronic lens.

  • Tim Ashley

    Can I steal that phrase ‘mechanical hygiene,’ please? It is quite brilliant!

  • As even Leica sensors have a hard time using and “deciphering” Leica lenses, there will undoubtedly be problems. In the real world, how many users will actually notice the fine print of the issue? The mere fact that an old M lens can be bolted on to the A7(R), look beautiful and produce not only more than just acceptable pictures, but will likely even outperform the proprietary M in some ways, will be good enough for me.

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