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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
  • richard rizzuto

    Question for you, I need to repair my bayonet mount on my sony 55mm 1.8. Pictures are fine, autofocus is fine, but it sits on the camera slightly bent to the left. I found the replacement part online for $67. Is the electrical piece of the mount easy to reattach to the circuit board?

  • John Cao

    My 3 year old sony sel35f18 does exactly the same, except it works sometimes but most times it behaves like you described. And it does not have a pattern of when to have the problem. When it’s working, it’s working… and all of sudden, it will stop working for sometime, and some days later, it might start working again.

  • Chinaka Obojiofor

    well mine isn’t working like yours, it is recognised by camera for a few seconds then it gives F–, then recognised by camera then F–, does it for like 4 times, then it stays as F–. the lens is in perfect condition, do you think it could be the main board or just the 3rd assembly?

  • Roger Cicala

    I’m afraid we don’t do outside repairs.

  • Rodrigo Madera

    Can you repair mine? have a noise all the time

  • Dave

    Too many horror stories about SONY lenses and their lame service. I own a SONY FS5, but I am not inclined to invest in SONY lenses. Pity their customer service is so poor.

  • Martin

    Hi,

    i have the same lens – and the same problem. In the oss part of the lens is a motor to set the f-stop. This glass is moving up and down freely. In my other zeiss lenses this glass stays fixed. So I think there should be some kind of detent which is broken now.

    But you cannot use this guide, cause the lens is different. I dissembled everything, but I could not split it into 3 parts like in the guide for the 2470z above. So there was no way for me to fix it, I could not find a way to get into this oss part of the lens – at least not without any technical instruction guide.

    After some research in the internet this seems to be a huge problem for the Sony SEL1670z. There are a lot of people complaining, that this is broken – it seems to come after some time of usage or when it was used on hot days.

    Good look on your lens.

  • Phyo Oo

    Hello.
    I have 16-70 f4 Zeiss . it didnt show the F number and cannot autofocus. Now i sent the lens to the service center at singapore. They reply me back the lens has a issue with lens barrels and aperture parts. They said the total repair cost will be 360 S$. Can you give me the advice?

  • SQLGuy

    I’ve fixed mine. Kind of brute force, in that I ended up replacing the 3rd assembly and the outer barrel assembly. Replacing the third assembly doesn’t require removing the front of the barrel and front element from the zoom barrel, but I did remove these originally – following the teardown here. I had a bit of trouble reassembling it (wouldn’t zoom full wide). That was because I had misaligned the front barrel when I’d reattached it. Your photos were very helpful in finding that issue. Overall, $240 in parts and what would have been 30 minutes labor, if I hadn’t had to figure out the alignment issue.

  • SQLGuy

    I am now more thinking it’s the aperture unit… maybe the motor. I pulled it apart again and removed the motor, and the aperture opened as I removed it, giving the impression that something was binding there. I verified that the aperture itself could be easily opened and closed, and still could be opened and closed pretty easily with the motor back in place. I reassembled it with the aperture wide open. When I attached it to a camera, it quickly stopped down to F8 or so, then went back into its loop of F8 or about F22, and gaining and losing communications with the body. Sadly, since the aperture isn’t available separately, I think the only choice will be to replace the whole 3rd assembly.

  • SQLGuy

    Actually, after opening it up one more time, and closing it up one more time, I think the problem is in the aperture mechanism. It seems to have difficulty fully opening. I took a look at the OSS unit, and it moves freely in both directions, and the coils and magnets seem fine. Will probably try one more time to see if I can do anything for the aperture mechanism.

  • SQLGuy

    I’m trying to repair one that was dropped. This writeup was really helpful in seeing how to disassemble it and how the larger aspects work. Mine seems to go into a failed POST loop of some sort. The camera will initially recognize it, and the aperture will open to maybe 5.6 or 6.3, then it will stop way down, and it looks like the OSS element moves quite a bit, then it stops. Somewhere in there the cameras loses communications with the lens and changes to F–. It never tries to focus.

    Physically it looks OK, other than a broken post where one of the mount screws attach. The focus voice coil is not loose like yours was, and I was able to move the focus element throughout its range by applying up to 1.2V to the coil. I’m thinking that maybe something is damaged in the OSS part, and I plan to open it up again to see whether I can see anything there. Any other ideas?

    Thanks,
    Paul

  • Martti O Suomivuori

    Just wondering whether I have the guts to see if my 16-70mm f/4.0 has the same problem.
    It rattles, that’s all it does.
    What glue did you use?

  • GW

    Thanks so much for posting this. Same thing happen to me on the same lens. Out of warranty and Sony store in HK wanted repairs for north of $600.

    For anyone in Hong Kong, this repair shop was able to do the repair for about $50 and they did a great job:
    Raymond
    Rm 2209 Pak Po Lee Comm. Ctre.
    1A Sai Yeung Choi St. South, Mongkok.
    Phone: 2332 9115

  • Tim Martin

    Thanks for publishing this. I am having the same symptoms with the same lens. The local repair shop refused to fix it and the warranty has expired. I think I am going to try this myself.

  • Roger Cicala

    Sorry Michael, we don’t carry parts. You might try Sony USA.

  • Michael Alan

    Hi, I submerged my camera and lens while shooting a waterfall. I was able to take apart the lens pretty easily, but damaged the big fat ribbon in this photo, http://wordpress.lensrentals.com/media/2015/04/M34A1913-1024×921.jpg. Anyway to order one from you?

    Michael

  • Roger Cicala

    Sony-Rob, unfortunately (at least in the U. S.) Sony doesn’t sell just the front element, the part is for the entire optical assembly and it costs nearly as much as a new lens.

    Roger

  • Sony-Rob

    Nice work on the teardown and repair.

    I have the same lens, but have damaged the front lens element. Can i buy a replacement glass? And is it a matter of unscrewing the front to replace? Any advice would be good.. (I am in Australia )

  • Paul

    Sony has no repair facilities in the USA. See my experience with Sony and (very imprecise) Precision camera when my 16-35mm Sony/Zeiss f/4 consistently failed under cold conditions.

    http://www.getdpi.com/forum/sony/54818-dead-sony-16-35mm-f-4-sony-farms-out-warranty-service-usa.html

    Must we consider Sony “Pro grade” products disposable?

    -Paul

  • Thanks, that’s what I supposed.

    -Ross

  • Roger Cicala

    Ross, what I am calling the optical block is the small central group of the lens containing most of the elements, the IS unit, focusing unit etc.

  • Roger, could you please enlighten me about what the “optical block” is?

    Thanks, Ross

  • The teardown was very interesting. I sent my 24-70 FE to Precision Camera for cleaning and maintenance, normally included free under the new Sony Imaging Pro Support program. They reported that they found physical damage on the optical block, a chip at the extreme edge of the rear element. I never saw this problem, so I assume that it caused no ill effects (?) or that it happened at Precision Camera. They originally quoted $916.93 for a repair — you can buy the lens new for not much more than that!

    Luckily, I was covered under a three-year Service Plan with Accidental Damage from Handling, and after several days to get approval under this coverage, they repaired the lens and sent it back without charge. They say that they replaced the optical block, did a complete repair and returned all functions to factory specs, and did a “complete cleaning (internal-external) and optical system.”

    What exactly is the optical block? Is that all of the of the glass elements, excepting the front element? Should this lens be as good, maybe better, than new?

    Thanks, Ross

  • Ian

    If I remember correctly, the Sony lens are designed to be repaired ‘in house’ rather than being needed to be sent to specific parts of the world. ( My Sigma 10-20 needed to go to Japan from the UK for repairs and had a 6 week turnaround )
    This allows anyone in a competent repair shop to fix your lens should it break when you were on holiday, or on a workshop for instance, should you lose your shooting capabilities.
    This may explain its rather basic structure. ( my brother in law repairs Sony parts in-house as a Sony engineer )

  • Roger Cicala

    Mike, I can’t, not because I’m under any nondisclosure, but because I have no direct knowledge other than exactly what you have already observed. Prices have skyrocketed and repair quality is deteriorating.

  • A (sorta) concur with Albert: that’s a DC voice coil motor. It can deliver very precise movements rapidly and apply quite a large force when needed (that might be a consideration of a ultrasonic piezo motor).

    The glue seems a reasonable solution to attach the voice coil to the lens assembly. The optomech guy is trying to keep the mass down (to keep focus speed up for a given current/power consumption) so they omit a coil form too (the coil is self-supporting). The problem might be either not enough glue (they try to minimize that too) or perhaps there was a sharp blow (perhaps tranverse to the lens axis) that cracked the glue. Or perhaps a part wasn’t properly prepared for the glue.

    The “position sensor” might be a Hall Effect device (e.g. if they’re detecting a small moving magnet on the lens assembly to determine position). It would give continuous lens position with no contact so no friction on lens assembly. But with CDAF (or even CDAF with a PDAF hint) you would usually pull the lens to closest focus then move it out until you get sharp focus (then a little dip and pull it back a little). The position sensor would be mostly to report focal length/distance for EXIF data. They could use it for power-on diagnostics too.

    Sigma have used DC voice coil motors for AF in their inexpensive Sony (and micro FourThird) 19mm and 30mm primes. They work well (they’re quick to focus) though they do have a disconcerting rattle when powered off as the lens element is not locked when powered off.

  • Mike Ogle

    Since Sony has closed out its Mexican repair facility and gone to 3rd party repairs (Precision), the prices have really skyrocketed. Consumers are not happy. I understand that Lens Rental has worked out a deal with Sony to supply replacements in their Pro program, can you comment on this Roger?

  • Rod Bracken

    Roger,
    Very informative (as always). Have you had any issues with Sony lenses not registering the aperture when you mount them to a camera? My SEL70200G wouldn’t report the aperture when I mounted it on either my NEX-7 or A7R. I sent it to Precision Camera for repair and they deemed it unrepairable. I’m still working with Sony trying to get this lens replace.

  • Interesting teardown Roger.

    Have you found the same design features on the other FE lenses?

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