Teardowns and Disassembly

Tearing Down the Sony 24-70 f/4 ZA OSS Vario Tessar

Published April 7, 2015

Those of you who read our teardowns know that we commonly are tearing down Canon or Nikon mount lenses. The reasons are pretty simple and it basically comes down to the fact that we have a lot more of those lenses. If we have a lot more it’s less of a problem to take a couple out of stock for a teardown. Plus, we’re more likely to be doing repairs on them in-house so we need to know the layout. Not to mention, since we spend most of our day inside those lenses, we know our way around them pretty well and don’t look to stupid when we do a teardown.

But people who shoot Sony, or Pentax, or micro 4/3 ask us to rip apart their lenses, too. We’ve avoided doing that because of the above reasons and because we rarely try to repair them. But in the last few months, we’ve gotten motivated to look inside Sony E mount lenses. Partly it’s because we’re carrying a lot more of them. Partly it’s because repair costs on Sony lenses have become — well I like Sony, so let’s just say “fully valued.”

A few days ago, we sent a Sony 24-70 f/4 ZA OSS  to repair because it made a grinding noise and wouldn’t autofocus properly. That kind of thing happens all the time and the repair cost at most manufacturers is $200 to $300. When the service center told this would be an $800 repair, we decided to have them send it back and take a look inside ourselves.

“Self Portrait in a Vario-Tessar”. Lensrentals.com, 2015. Call for print prices. 

One thing I like to mention before we start an article is what my expectations were on the front end. We know the 24-70 f/4, like most of the new Sony E mount lenses, has electromagnetic, rather than helicoid, autofocus. We also know that there’s a bit more optical variability in these lenses (making me think optical adjustments are somewhat limited). So I rather expected we would find the internal optics/electromechanical parts of the lens might be completely sealed; not repairable, only replaceable. That would go along with high repair costs, too.

I also need to mention that we do NOT know how to repair Sony lenses. We don’t have access to repair manuals, etc. This is not intended as a how-to-repair-your-lens article. We just thought you might enjoy watching us mess around with it and see what’s inside of it. Oh, and the usual disclaimers — if you do this yourself, it’s on your nickel. Also, I can’t respond to emails asking how to do this or that: you are many; I am one, and I really am supposed to be working much of the day.

By the way, if you feel the need to comment that we don’t take beautifully lit product shots during a teardown, save it for someone who cares. We’re tearing down a lens, trying to figure out how to fix it, and remembering how to put it all back together. We take a few hand-held shots while we do it, under the very harsh tungsten lighting we need to peer into the various nooks and crannies of the lens, so we can show it to you. If you want to look at beautiful pictures, go to Peter Lik’s gallery or something.

So Let’s Go Break Things!

The bayonet mount comes off in the usual fashion: remove the four screws.  With Sony lenses it’s usually simpler to disconnect the electrode flex from circuit board than to remove the electrodes from the bayonet.

Roger Cicala, Lensrentals.com, 2015

 

Sony doesn’t hold their PCBs in with screws like most manufacturers, they use adhesive rubber bumpers. I don’t have the slightest idea if it’s an advantage or disadvantage, it’s just different.

Roger Cicala, Lensrentals.com, 2015

 

With the PCB removed we get access to the four screws holding the rear barrel in place and can remove it.

Roger Cicala, Lensrentals.com, 2015

 

That exposes the zoom keys, one on either side, that have to be removed to let us take the zoom ring off.

Roger Cicala, Lensrentals.com, 2015

 

Since we weren’t sure how the connections ran, we removed the screws holding the zoom position sensor before removing the zoom ring; part of the sensor was under the zoom ring.

Roger Cicala, Lensrentals.com, 2015

 

The zoom ring slides right off once the keys are removed and it’s rotated to the right position.

Roger Cicala, Lensrentals.com, 2015

 

Now we can look at the working side of the zoom position sensor. It’s a simple slide inserted into a rotating helicoid (red arrows). That’s different than the electrical brushes and positions sensors that most lenses use, but certainly cleaner and simpler. I like it. Sure, the plastic tab could snap off, but the very thin metal brushes bend too, so I would think this is at least as reliable as a brush system.

Roger Cicala, Lensrentals.com, 2015

 

Moving right along, taking out another set of screws lets us remove the inner barrel.

Roger Cicala, Lensrentals.com, 2015

 

With the inner barrel removed we can see another nice touch that I wish all the other manufacturers would do. Sony places some cushioning strips between the extending barrel and the rest of the lens. This makes things move more smoothly and also prevents the plastic-on-plastic catches that sometimes develop with extending barrels.

Roger Cicala, Lensrentals.com, 2015

 

The front barrel is held on with three screws inserted into large brass inserts, just like most lenses use. Removing these lets us remove the extending barrel.

Roger Cicala, Lensrentals.com, 2015

 

It’s probably worth noting that with all the disassembly we’ve done, this is the first time we’ve removed any of the lens elements. The front element is removed with the extending barrel. Everything else we’ve removed has simply been structural or mechanical.

Roger Cicala, Lensrentals.com, 2015

 

What we’re left with is the central core of the lens. This contains all of the glass (except the front element), the OSS unit, aperture, focusing motor, etc.

Roger Cicala, Lensrentals.com, 2015

 

We examined it pretty carefully, looking for optically adjustable elements. There were the usual helicoid sliding collars (red lines) and one set of elements that had what appeared to be eccentric adjustable collars on them (blue arrow), but closer examination showed those collars seemed to be holding the OS element so it’s unlikely they have any optical adjusting capability.

Roger Cicala, Lensrentals.com, 2015

 

At any rate, removing the mount-side set of collars lets us remove the helicoid barrel.

Roger Cicala, Lensrentals.com, 2015

 

I should mention that these are thick, robust collars that look like they should hold up well.

Roger Cicala, Lensrentals.com, 2015

 

With those collars removed, the helicoid barrel slides right off.

Roger Cicala, Lensrentals.com, 2015

 

This barrel contains the second lens element, so now we have those two large elements removed and sitting in their barrels on the back bench.

Roger Cicala, Lensrentals.com, 2015

 

And what we are left working on is the small inner core of the lens, which contains all the other glass elements, the OS unit, autofocus unit, aperture assembly (you can see that on the top), etc. This is where I expected we’d find, like many micro 4/3 lenses, this entire unit would be sealed and could only be replaced, not repaired.

Roger Cicala, Lensrentals.com, 2015

 

Roger Cicala, Lensrentals.com, 2015

 

But as very occasionally happens (very occasionally being defined as about 20 times a day), I was wrong less correct than I would like to have been. There were some nice obvious screws just waiting to be removed, letting us take the rear group off.

Roger Cicala, Lensrentals.com, 2015

 

With this group removed we can look directly down at the focusing element and the electromagnetic focusing mechanism. The focusing element is obvious. Rather than being moved by rotating through slanted helicoid tracks, it slides directly up and down on two metal posts (green lines), moved by the electromagnetic (red line), that receives power from a long, mobile flex cable (blue line). That’s a very different system than most SLR lenses.

Roger Cicala, Lensrentals.com, 2015

 

Since this lens couldn’t autofocus we took a look at the focus position sensor.

Roger Cicala, Lensrentals.com, 2015

 

Focus position is probably more critical than zoom position, and this seems to be an electro-magnetic type of sensor (I’m not 100% certain – it might be some different kind of optical sensor), but at any rate, there were no obvious signs that anything was amiss with the sensor mechanism. (I know you’re thinking, so if you don’t even know what it is, how could you tell if something was wrong? Well, we could tell if it had a cracked flex, or broken solder, or stuff like that. But it could also be deader than dead and we wouldn’t have a clue.)

Roger Cicala, Lensrentals.com, 2015

 

Since this lens was broken we were a bit more aggressive with messing with stuff we didn’t understand than we usually would be. We found out pretty quickly that the two metal rods the focusing element slides on could be removed.

Roger Cicala, Lensrentals.com, 2015

 

With the posts removed, we could pull the focusing assembly out of the barrel. You can see that the optical element just slides up and down within the eletromagnetic motor assembly.

Roger Cicala, Lensrentals.com, 2015

 

We didn’t have a lot of hope that we’d be able to fix things in here since we haven’t the slightest clue how it works. But once we started looking around we found an apparent problem. There was a dot of glue that apparently should attach the electromagnetic coil to the plastic housing of the focusing element, but the coil had become separated. You could see the imprints of coil in the glue, so it seemed pretty obvious they should be glued together.

Roger Cicala, Lensrentals.com, 2015

 

We figured we had nothing to lose, so we glued it back. (Do not try this at home unless you have a good ventilated hood or something similar. Glue fumes can totally eat the coating off of lens elements. Or can add a layer of white residue. Depends on what glue you pick.)

Much to our shock, the lens works perfectly fine after our homemade repair; at least it has so far. We’ll keep it around here for a long while, though, to see if the glue we used fails since we don’t know exactly what type of glue is originally used and how our choice (made on the scientific basis of “well, it kind of looks like this”) will hold up over time.

This concludes our little disassembly and triumphant random repair story, but you know me, I’ll have a few random comments to make.

Roger’s $0.02

My summary is that the 24-70 f/4 OSS Vario-Sonar is just what I’ve come to expect from Sony lately. Some amazingly great stuff, some rather apparently stupid stuff, and some stuff that I don’t have enough knowledge to comment on.

The amazingly great stuff should be obvious. The lens is very cleanly designed and modular. We’d never been inside of one before, but had it completely disassembled in less than 45 minutes (it will take less than 30 minutes next time). The construction is robust for a small lens and there are several very nice touches, like the cushions under the extending barrel to keep the mechanism smooth.

The apparently stupid parts are pretty obvious, too. This lens seems beautifully designed for easy reparability, and I can think of no reason it’s more expensive to repair than similar lenses from other brands. Charging such high prices is going to alienate customers pretty quickly. It’s not too hard to get new customers, but it’s almost impossible to regain a lost customer.

I would add that glue applied to smooth surfaces is unlikely to hold up forever on a frequently moving part where the force of movement is across the axis of the glue. A tiny notch or clamp from the plastic mount to the coil would have created a much more robust connection and not cost a dime if someone had simply designed it properly in the first place. So much of the lens is so thoughtfully engineered that it’s a shame such a critical connection apparently was engineered as an afterthought.

It seems that there’s not much optical adjustment capability in this lens. There are some shimable areas under the front group that we didn’t show, and there may be some other adjustments we haven’t recognized on a single disassembly (possible, not likely). In theory, you could make a lens so tightly toleranced that it doesn’t need adjustment, or could test it at every step of assembly removing and replacing incompatible elements. But those two options are far too expensive for me to believe that they are actually being done, and anecdotal reports of significant copy-to-copy variation suggest they aren’t. On the other hand, an f/4 lens doesn’t need to be as critically adjusted as an f/1.4 or even an f/2.8 lens would.

I don’t have a clue if electromagnetic focus is more or less accurate, reliable, durable, or expensive compared to the standard USM type AF seen in most SLR lenses. But from most of the comments and my own experience using the lenses, it certainly seems to work quite well.

After we’ve worked on some more of these lenses (and it seems likely we’ll have to do that) we may get a better idea about some of these things. But this first glimpse was interesting.

 

Roger Cicala and Aaron Closz

Lensrentals.com

April, 2015

Author: Roger Cicala

I’m Roger and I am the founder of Lensrentals.com. Hailed as one of the optic nerds here, I enjoy shooting collimated light through 30X microscope objectives in my spare time. When I do take real pictures I like using something different: a Medium format, or Pentax K1, or a Sony RX1R.

Posted in Teardowns and Disassembly
  • R. Edelman

    It seems that Sony does not understand glue. The lens shade on my Sony-Zeiss FE 35 mm f 2.8 came apart in two pieces. The two pieces were held together with some black rubber cement, the remnants of which could be peeled off with a finger. A little super glue gel has permanently repaired the part. The hood is easily removed, and thus can be repaired off of the lens, so no risk of fumes or glue getting to the lens elements.

  • Graham.

    Hi Roger.
    Thanks for yet another very informative tear down article,
    I have to say if I got that far I would probably have reassembled it and sent it in with a strongly worded message about how this would be a warranty repair, a failed glue dab, ludicrous to try to charge $800 unless they accidentally quoted in HK$, which is approximately $100!
    At least Dick Turpin had the decency to use a mask and pistol to rob people!

    Cheers, Graham.

  • Ken

    Thanks for the teardown, Roger, this piece had some really ‘enlightening’ information. Coming from a background in precision engineering I caught myself staring at that glued connection in utter disbelief. It’s just as it has been primarily designed to break at some point in time or after such a lens has fallen or taken an impact of some sort – the blame would automatically be placed on the poor soul to whom it happened. Warranty? You dropped it – that’s $800, Amigo.
    Dang, I was in the market for an A7R and some glass but I will sure as hell reconsider my choice.

    Thanks again!

  • Daryl

    Thanks Roger, great read. btw- pictures are good also. The $800 repair is not unlike Kodak repairs, they charge 50% of new, basically flat rate repair, much higher than others, circa 1970’s.

  • Holy cow, $800 for the repair by Sony. That essentially makes it a throw away item id something breaks for me since, through a corporate partnership discount program, I can get that lens for just under $1000. Sony is out of their minds.

  • Nathan

    Hi Mr Cicala,
    I very much enjoy your blog, please keep up the fine work.
    The scientific rigor you employ seems to be sorely lacking from most other sources of lens reviews I’ve found on the internet.
    Very little of it is relevant to my actual photography, however, as I shoot film. What I would get a real kick out of is seeing some classic, culty or interesting lenses subjected to your technical scrutiny.
    Things like the Helios 58/2, the Hologon, early Tessars, the Macro-Kilar, some of the 40/2.8 pancakes.
    If you were feeling particularly daring, extracting the lenses out of fabled film compacts like the Hexar, Ricoh GR or Olympus mju and testing them would be a great read.
    Or on a more selfish note, the Canon FDn 50/1.2L and 85/1.2L 🙂 FD glass is having a bit of an eBay rennaissance thanks to the Sony A7 cameras being the first full frame digital able to mount them. I have these two, and they are just lovely, as sharp as any sensible person would need them to be on film at any aperture. In fact, forum grumblers and bloggers occasionally claim that they’re sharper than their EF replacements, owing to their manual focus nature. I don’t see how that would be the case, as I thought the EF versions were basically unit focusing lenses aside from their floating rear elements, but the FD series’ long obsolescence has seen them evade MTF50 tesing for far too long.
    And as I already own mine I wouldn’t suffer from the attendant clamour for them if they turned out to be really good…
    Unfortunately I can’t proffer mine for testing as I live in Australia, but I’m sure your network of gear-hoarding friends is vast.
    And also apologies if this is a terrible place to post this, but it seemed as good a way to get a hold of you as any!
    Regards,
    Nathan.

  • I was already leery about the prices Sony is asking for its FE lenses. Now that I know they have the audacity to charge two-thirds the retail price for a simple repair (one wonders whether their repair techs actually inspected the lens or just sent back a flat estimate), there’s no way in hell I’d buy a Sony FE lens. But don’t worry Roger, I still might rent one. ; – )

  • David

    Thanks for the dissection. It’s interesting to hear your experienced (and relatively lingquistically gifted) analysis regarding little details. I also wonder how Zony lenses differ innardly from Zeiss lenses for Sony mounts (Touits and Loxias) on some rather generalized level (since there are no equivalents). In part because human beings like generalizing, in part because technical details are inneresting.

    In regards to Sony audio devices I recall people at Apple asking “What is that thing” regarding my NH900 when I worked as tech supp, and the thing still works. It still isn’t as sexy looking as the NH1.

  • Markus

    So, is it a fact that (even the “Pro” line of) lenses for mirrorless systems are constructed in a simpler way and are less adjustable and repairable than lenses for DSLR’s?

    And if so – is there a common reason (apart from just manufacturing cost)?

  • tn1krr

    Great article as usual. I’m a Sony FE shooter, but to cover myself from these things I’ve kind of factored in the price of 4 year full coverage into every lens purchase. So when I consider a lens I put the full coverage extra into the price before making decisions. Not perfect, but qurantees I get decent mileage for my purchases.

  • Brian

    My experience with all 3 Sony audio devices I’ve owned (all near the top of the range) is that something simple always goes wrong with them. In one case, it really looked like it was designed to fail in that way. Only 3 devices because eventually even I learn. I’ve been told that in Japan, Sony is known only for their ability to make things smaller than anyone else.

  • John

    I think Sony should make Sensor only, nothing else. Their SLR camera are also very weird. I am wondering if INTEL which the most advance fabrication in the world can make image-sensor. INTEL technology in Lithography is just too good.

  • Robbie

    I wonder if that glue was intended to also be on the inside of the coil instead of just the bottom. Then it would have a strong shear connection to the element instead of the tension one shown. Might be a manufacturing issue rather than design.

  • Roger Knight

    Matthew,
    Its likely that part of Sony’s appeal comes from digital photographers who have grown up with most, or all, preeminent electronics coming from Sony, Samsung, Panasonic, etc. To them, Canon, Leitz, Nikon, Zeiss, etc. are simply quaint, last century names awaiting the guidance of the aforementioned technological giants.

  • Albert

    Hi, based on my experience with linear motors (its appears to be a synchronous linear motor) the used glue is normally epoxy. In fact, standard industrial ironless linear motors have their coils supported by this epoxy resin. To be precise the coils are fully enclosed in epoxy:). And these motors can provide forces in the order of hundreds of Newtons. So it’s a very common and tested solution for fixing the coils. Maybe they only need more quantity of glue…

    Albert.

  • omer

    Great article as usual
    Roger you guys should consider to add repair service in addition to rent
    Many will be glad to have you take care of thier lenses

  • Funny you should put “Roger’s $0.02” at the end, because that may be the value of the glue you used, instead of an $800 repair bill.

    Considering that a trained Sony technician could have this lens apart and back together in well under an hour, I’m calling major shenanigans on Sony’s repair estimate. Just another reason I am completely confused as to why the bandwagoning has managed to rage on for so long…

    Pentax DSLRs have IBIS.

    Nikon’s D810 now has zebra stripes, and the next generation will surely have marching ants too. (Oh and Magic Lantern has brought both to Canon for years)

    A D750 and 50mm f/1.8 G weighs only a couple ounces more than an A72 and the new 55 1.8 Zeiss, yet because of the price of the Zeiss, the Nikon kit actually costs a couple hundred bucks less.

    Lastly, Nikon can completely tear-down and optically calibrate a lens as big as a 24-70 2.8 or 70-200 2.8, for about $600. (I’ve had it done three times)

    All while Sony throws crazy ideas at the wall to see what sticks. Wide-angle adapter lenses? F/4 zooms that actually weigh and/or cost more than their DSLR competition? (70-200 f/4, 24-70 f/4) And of course, the extremely high-priced lenses that are really only an advantage if you’re shooting 36-50+ megapixels wide open.

    Sony’s apple-like influence on the masses continues to perplex me.

    =Matt=

  • “Call for print prices.”

    Anyone that has been following the comment threads will realize that Roger wins the Internets today with that line.

  • I doubt that the zoom position sensor is more reliable than a brush system. This looks pretty much like a simple carbon fader, which should wear out a lot faster than a gold plated brush. On the other hand, it’ll surely last a couple of years, and then there still is the Sony Service with appealing repair prices… 😉

  • Muddy

    Interesting article. I just bought this lens and the comments about sample variability intrigues me. I got a deal on mine and expected an average wlakaround zoom. I am pleased to say that my 24-70 outresolves my Sony Zeiss 35mm at higher ISO levels and at 70mm kicks my 70-200 f4.5 into touch.

  • Please dissect some Fujinons too!

    (XF 50-140/2.8, anyone?)

  • Jon

    That glue bit is completely unacceptable, and Zeiss should be ashamed of themselves for letting Sony print their name on these lenses.

    I was going to buy the Sony-Zeiss FE 16-35 f/4 lens, but after seeing this and the ridiculously high Sony repair costs, I’m thinking I’d rather buy the Canon 16-35 F/4 and use an adapter on my A7r..

  • David Braddon-Mitchell

    I wonder if Sony’s new Pro Service deal for photographers that they say they are rolling out in various countries will give better pricing?

    Interesting about the anecdotal reports of massive sample variation. That would explain a lot: less so than the 16-70 there have been huge discrepancies between the reviews (even reviews all basically doing imatest at the same distance). I was always surprised by the complaints about the wide end: mine’s lovely at 24 over most of the field, and not bad in the corners. 70mm is a bit meh: lower resolution and contrast overall. Indeed, my copy looks like DXOs copy tests. But other, reliable, people have said they have copies no good at the wide end.

    So, selfishly that’s good. But if it ever goes out of whack it looks like I’m plumb out of luck! I hope the primes are more repairable…

  • “Call for print prices.”

    Well done, the humor is always great and your teardown made me glad I sold the 24-70 a few months after owning it. I’d love to see the reason for shooting Sony torn down; the 135 1.8!

  • John D

    Long time Canon shooter that has been tempted by Sony. Lenses and cameras need to be repaired from time to time. $800 is outrageous. Canon has wonderful service and after the CPS discount a Canon repair might only cost 25% of a Sony repair. Sony is not so tempting now. Thanks Roger. Great information as always

  • Brian B

    Thanks for the teardown Roger!

    I’m impressed!

    Maybe, just maybe, articles like these will touch a nerve at Sony, leading to either, cheaper repairs, or small improvements in design!

  • Barus

    Looking through the rear element, you can see the focusing element sliding up and down by tilting the lens. You can even see the rods.

  • Even though the 24-70mm may be the weakest of the FE lineup I still think that modern lens designs are incredibly complex!

  • The FE 24-70 is the weakest FE lens that I have used, which is a shame because it’s the bread and butter lens for many photographers, me included. Here’s to hoping Sony puts out a version II of this lens that is more consistent copy to copy and is sharper throughout its range. That unglued bit has me a bit nervous.

  • John

    So this lens has wide variations copy to copy and not reliable. I am glad not by not taking Sony system from the first time. I cannot believe SONY-Zeiss lens is design so poorly.

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