Equipment

Assumptions, Expectations, and Plastic Mounts

Published December 31, 2013

Photography companies love catchword marketing. They like catchwords because photographers make assumptions about what those words mean, even though the words really don’t mean anything. So basically, they say nothing, but it makes you believe something.

Two of my favorite examples are “professional quality construction” and “weather resistance”.  When I read those terms, my brain translates them to “Blah, blah, blah. Blah, blah.” They are subjective terms, just like ‘elegant design’ and ‘innovative styling’.

Most photographers, though, make all kinds of assumptions about what those catchwords mean, and have all kinds of expectations about the equipment that is described by these largely meaningless bits of marketing. We all know what Oscar Wilde said the word assume really means. Expectations, of course, are simply a down payment on future disappointment.

I have watched several world-class internet meltdowns with great amusement recently. All were started when photographers found out that their assumptions and expectations about what catchwords meant were wrong. They became a firestorm when people added a lot of ‘facts’ that weren’t really facts.

Plastic Mounts and Professional Construction

Much of the recent internet rioting was triggered by some Olympus 12-40 lenses that broke off at the plastic mount (the mount is the internal part of the lens where the bayonet — the metal part that twists into the camera — attaches by several screws). Several people reported their lenses broke at the mount with minimal force applied (a short fall or even pressure from other items in a camera bag). We ship those lenses all over the country and they seem no more likely to break than any other lens we stock. But apparently at least some of them had a weak mount.

What amused me was the absolute fury expressed by numerous photographers that a “professional quality” lens might have a plastic mount. I’ve looked up the term ‘professional quality’ everywhere and nowhere have I found it defined as ‘having an all-metal mount’. But some people are livid that it isn’t so. If you’ve read one of these posts on the internet lately, you’ve learned all kinds of things. . . none of which are true.

  • Most micro 4/3 lenses have metal mounts (they don’t – only one does that I recall).
  • All ‘professional quality’ lenses have metal mounts (they don’t, not even close to all do).
  • Micro 4/3 lenses and NEX lenses all have plastic mounts, but ‘real’ SLR lenses have metal mounts (not true on either side of the comma).
  • Plastic mounts are only used on cheap kit lenses and have only appeared in the last few years (They’ve been around for a long time on many lenses).
  • Lenses with plastic mounts break more frequently than lenses with metal mounts (Nothing suggests this).

I take apart lenses all day every day, so I was rather amazed to find all these facts spoken so dogmatically by people who claimed them to be absolutely true. I make it a rule never to argue with people who claim absolute knowledge, no matter how wrong they are. But I will occasionally show them pictures. So here are some pictures of the mounts of lenses that Aaron and I took apart for various reasons this morning.

Canon 35mm f/1.4 L lens. Released in 1998 (15 years ago), considered a Professional Quality lens, and certainly carrying a professional quality price. It has a plastic mount. In fact, we keep that mount as a stock part because we have to replace it every once in a while. It doesn’t break often, but we have hundreds of them and they do break once in a while.

 

Canon 35mm f/1.4 L with rear barrel removed, showing 4 plastic posts of the lens mount.

 

Panasonic-Leica 45mm Macro Elmarit f/2.8 m4/3 lens. I won’t argue about whether it’s a Professional lens, but it’s really good, really reliable, and quite expensive. It has a plastic mount despite online claims otherwise.

Panasonic-Leica 45mm. The 4 empty plastic holes are where the bayonet attaches. The 3 screws still in place attach this plastic piece to the next plastic piece in the lens barrel.

 

Sony 50mm f/1.8 NEX lens. Again, I’m not arguing Professional here, but this one is widely mentioned in the forums as ‘all-metal construction’. It has a metal shell, just like the Olympus 12-40mm, but the support pieces are plastic and the mount screws into plastic, just like the Olympus 12-40mm.

 

Sony 50mm f/1.8. The 4 hollow plastic posts are where the screws from the bayonet attach.

 

Canon 14mm f/2.8 Mk II L. I don’t think anyone argues this is a Professional Quality lens at a very professional cost. An ultra-reliable lens, but it certainly has a plastic mount. Not that we ever have to replace them. They never break here despite being far larger than the Olympus 12-40mm.

 

Canon 14mm f/2.8 II rear barrel showing hollow screw hole in polycarbonate inner barrel where the bayonet attaches.

 

Canon 24-70 f/2.8 L Mk I. A professional lens released in 2002. It weighs about 2 pounds; far larger than any two micro 4/3 lens combined. It is generally referred to as a tank because it never breaks (it has optical problems, but those occur at the front end, which is, oddly enough, entirely made of metal). The plastic mount never breaks despite holding up 2 pounds of lens. Trust me on that, we’ve carried hundreds and hundreds of these for years and never had a mount break. (As an aside, the Mk II version has a metal mount, despite being lighter. I’m not sure why.)

 

Canon 24-70 f/2.8 Mk I. That big beast is easily and reliably supported on it’s 4 polycarbonate screw mounts.

 

The Tamron 24-70 f/2.8 VC lens. I include this one just for completeness, because it’s another large lens and at least one online authority has stated it has a metal mount. Sorry, there’s no metal back there at all.

 

Tamron 24-70 f/2.8 VC. Another large lens easily and reliably supported on it's plastic internal mounts.
Lens mount with empty plastic holes that attach the bayonet, and screws remaining in holes attaching this to the next barrel piece.

 

Attention Fanboys: Just because your favorite lens isn’t shown here doesn’t mean it doesn’t have plastic mounts. Lenses of 70-200 f/2.8 size and up all have metal internal mounts (as best I can recall), but lenses smaller than that may be either metal or plastic. All Zeiss ZE and ZF SLR lenses have metal internal mounts (but not Zeiss-designed lenses for other brands). Nikons are more likely to have metal mounts than other brands, but they have a fair amount of plastic-mount lenses, too. Otherwise, the majority of lenses have internal plastic mounts.

Does it make any difference? I looked at the Lensrentals’ reliability data for the last several years (several thousand repairs), and there’s no higher failure rate with plastic mount lenses. They have, if anything, a bit lower failure rate, but it’s not a significant difference.

When a plastic mount does break, people tend to freak out a bit because the lens is so obviously broken. From a repair standpoint, though, we love them. It takes 15 minutes to replace a broken plastic mount and the lens is as good as new. Metal mount lenses don’t break like that. Instead internal components and lens elements get shifted and bent. It can take several hours to return one of those to optical alignment.

So What Does It Mean?

Absolutely nothing except that internet hysteria is alive and well. By my latest count, during the last two weeks 7,216 internet experts have claimed it is an absolute fact that plastic internal mounts are a new, cheap, poor quality substitute for internal metal mounts. The pictures above suggest otherwise.

The pictures show that for many years lots of very large, very high-quality, professional-grade lenses have had plastic internal mounts. Guess what? They didn’t all self destruct. In fact several of them are widely considered particularly rugged. Looking at 7 years worth of data involving around 20,000 lenses I can’t find any suggestion that plastic mount lenses, in general, fail more than metal mount lenses. Sure, there are certain lenses that fail more than others, but not because they have a plastic mount.

In theory, plastic mounts might be better, worse, or no different than metal as far as reliability goes. There are logical arguments for each.

Obviously a few Olympus 12-40mm lenses have broken at the mount. It may be there was a batch of badly molded mounts. It may be a design flaw. It may just be random chance – a few of everything break. But it’s not just because the mount is plastic.

I do like taking this opportunity to remind everyone that marketing catchwords like ‘Professional Grade’ mean very little. If they say it has 16 megapixels they’ve told you a fact. If they say  ‘Professional Grade’ that’s a word with no clear definition. It probably means ‘built better than some of our cheap stuff’.

Speaking of Catchwords

As long as we’re on the subject of catchwords, it’s probably worth tackling ‘Weather Sealed’ or ‘Weather Resistant’ next. Many people seem to believe that means ‘waterproof’. When you take lenses apart all day you find out it usually means ‘we put a strip of foam rubber behind the front and rear elements and scotch tape over the access holes under the rubber rings’.

 

Strip of foamed rubber that sits behind the front element of a ‘weather sealed’ lens.

 

Tape over access holes in a weather sealed lens.

 

It’s better than no weather sealing, certainly. And some (but not all) ‘weather sealed’ lenses also have internal gaskets around barrel joints and other added bits seals. But I haven’t seen one manufacturer yet tell us exactly what weather their lens is sealed against. Snow? Rain? Sunshine? Wind? Well, it can’t be wind because the lenses we spend the most time taking dust out of are mostly ‘weather sealed’.

It’s very different with different manufacturers. You can assume whatever you like, but when you send your lens in for repair, ‘weather sealed’ still means ‘the warranty doesn’t cover water damage’.

The truth is, terms like Professional Grade and Weather Resistant are nearly as vague as ‘innovative technology’ and ‘stylish design’. I’m certain it’s only a matter of time before I see an online post that says, “I bought this camera because the manufacturer said it had stylish design, but it’s butt-ugly. I think we should start a class-action lawsuit for false advertising”.

Roger Cicala and Aaron Closz

Lensrentals.com

December, 2013

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 Equipment
  • Ota

    The mentioned internet experts overlook that plastics is not the same every time. Most people think automatically about the thin carrier bag from the supermarket or another throw-away cheap product when hearing about plastics. The same people have a big airplane in front of their inner eyes when speaking about a failsafe, lightweight and sophisticated metal construction.
    These people probably don’k know the story of the first commercial (bad designed) all-metal jetliner: http://en.wikipedia.org/wiki/De_Havilland_Comet. They also don’t know that a plastic composite is used as a primary airframe construction material in the Boeing’s 787 Dreamliner. And they have forgotten the number of the killed race drivers in the years before the plastic (composite) cockpits were introduced in F1 race cars. Not only the race cars, our every-day-cars are also much more safe than 30-40 years ago. The car bodies were made of welded steel in our fathers’ time. A lot of parts of today’s cars are glued together (primarily for safety) using a plastic adhesive. Not every innovation leading to an increased use of plastics is driven by economy alone, the new technology doesn’t make the cars cheaper.
    The glue used in car body assembling is nothing else as a (properly applied) plastics. We use another platics for bags or pipes and another for airplanes or e.g. tanks in chemical plants. Still another brand of plastics can be the first choice in the lens construction. It’ll serve failsafe as far as the design is equally proper.
    Not the question “Metal or plastics?” ist the the right one. The right question is: “Is the material selection AND the applied design approriate?” This AND is crucial, not the material alone.

  • Roger Cicala

    Swamp Yankee, we get a fair number of cameras and lenses that come back water damaged – a couple a month or so. The majority are “weather resistant”. I assume that’s because people are more aggressive about letting them get wet.

  • Roger Cicala

    iamclaus, we do carry Pentax gear. Not to mention I personally shoot a K3. And I have seen demonstrations of Pentax cameras and lenses under running water.

    Which doesn’t change the fact that their warranty on weather sealed gear doesn’t cover water damage.

  • Toshik

    It seems for me that:
    1). People confuse terms bayonet and mount. As you can clearly see if bayonet is metal or plastic (in cheap lenses), you can’t see what mount is made of inside.

    2). As for weather sealed i totally agree, except latest Nikon AW1 which is stated as waterproof down to 15 meters (49 ft), shockproof from up to 2 meters (6.6 ft), so you can definitely swim with it.

    But we shouldn’t confuse waterproof and weather sealed which many people do.

  • Toshik

    It seems for me that:
    1). People confuse terms bayonet and mount. As you can clearly see if bayonet is metal or plastic (in cheap lenses), you can’t see what mount is made of inside.

    2). As for weather sealed i totally agree, except latest Nikon AW1 which is stated as waterproof down to 15 meters (49 ft), shockproof from up to 2 meters (6.6 ft), so you can definitely swim with it.

    But we shouldn’t confuse waterproof and weather sealed which many people do.

  • Geoff H

    I quote… “But I haven’t seen one manufacturer yet tell us exactly what weather their lens is sealed against.” however standards do exist for weather/water proofing and whilst traditional lens makers don’t tend to use these standards there are manufacturers who do and I deal with a number of security camera makers who sell IP67 rated cameras, some of which have inter changeable lenses.

  • EnPassant

    Thank you for the explaniton!
    However all these nice photos does in fact support the conclusion that the Olympus 12-40 lens has a design flaw.

    From the photos of a broken 12-40, http://www.mu-43.com/showthread.php?t=56256 the plastic mounts are just thick enough for the screws and not extra thick for added strength.
    The only, loose support is the circuit board, which however doesn’t seem to support the top of the plastic screw-mounts, giving wiggle space and a breaking point.

    The lenses in above photos having close to similar construction are all lighter and therefore doesn’t put as much stress to the mount when mounted on the camera.

    The heavier lenses on the other hand either have thicker plastic around the screw hole or much better support for it.

    While the broken lenses so far mostly may be odd exemples of bad material or something going wrong in the manufacture process the construction still doesn’t look strong enough for such a relative heavy lens. I therefore think Olympus should rework the circuit board to enable a more solid construction of the screw mount.

  • iamclaus

    Shame you don’t carry Pentax gear in your inventory… I’m curious to know how their definition of “weather resistant” lenses compares against the competition. In real-world terms, I can only vouch for the DA 18-55mm WR and DA* 50-135mm, knowing they can easily withstand being dunked and splashed repeatedly… (so far…)

  • SwampYankee

    Great Article, thanks. I don’t really care what the mount is as long as it works. I’m intrigued by the weather sealed comments though. Do you get many lenses back that are weather damaged? If so how many are “weather sealed” that come back with water damage? thanks

  • Tony

    People tend to believe what they are prejudiced to believe. I’ve gotten tired of telling people that if there is no sealing performance specification cited, it simply isn’t sealed – end of story. You never see a camera manufacturer telling us that a given piece of gear meets the requirements of, for example, IP54 (at a minimum). http://en.wikipedia.org/wiki/IP_Code

    As for mounts, the geometries of the parts play at least as important a role as the material choice. That is too sophisticated a concept for most internet shouting matches. You were wise to bring up the subject of the load path (what one load-bearing piece is attached to next in the line). The deadliest structural collapse in US history provides an excellent example of what can happen when perfectly appropriate materials are used poorly: Google “Hyatt Regency walkway collapse 1981”.

  • A

    Well said Roger!

    Fully agree about people reading meaning into words where there’s no meaning to them. I’d step back a level; and say my favourite word has to be “quality”; it’s totally meaningless without qualification.

    Quality lens!

    Yes, the lens has quality. Specifically the quality is “made of soggy cardboard”, but that’s a quality; right? 😉

  • Thankyou Thankyou Thankyou. Finally some thoughtful and helpful comments on an obviously near hysterical over-reaction to a few reported mount breaks on the new Olympus 12-40mm f2.8 lens.

    Who knows, there may actually be a design or manufacturing issue with the plastic mount in the 12-40, and it’s always good to report and discuss those issues, but as you pointed out, there was way to much wrong information being purported as fact, which only clouds the issue.

    And thank you, Roger, for your thoughts on weather sealing and marketing hype. You are providing a wonderful service to our community with you first hand, professional observations.

  • A

    Well said Roger!

    Fully agree about people reading meaning into words without any meaning being behind them. I’d step back a level; and say my favourite word has to be “quality”; it’s totally meaningless without qualification.

    Quality lens!

    Yes, the lens has quality. Specifically the quality is “made of soggy cardboard”, but that’s a quality; right? 😉

  • Charles Lanteigne

    Many years ago (I was, relatively speaking, just starting photography) I had bought a 70-200mm 2.8 IS lens. I had managed to get field-level access to shoot a football game and I was very excited, but when the day came, it was raining. Not just little droplets—it was *pouring*.

    I put a plastic bag around my camera, held in place with a rubber band close to the mount (so I could still lift the plastic and look on the screen if needed). I was confident that the lens didn’t need protection, since it was “weather sealed”!

    I’ve never been this completely drenched in my life, standing in that kind of rain for over an hour. At one point, one of the seasoned photographers was looking at me with inquisitive eyes, since I had no protection on the lens whatsoever (he was shooting under an umbrella attached to his backpack or something). It didn’t even cross my mind that there could be something wrong with what I was doing, since I was confident it was designed for this kind of thing.

    Absolutely nothing happened to the lens—it’s still working perfectly to this day, years later. But looking back at what I did, oh god… I can now understand why the other photographer was looking at me. I would obviously not recommend anybody doing this, but it worked just fine for me that one time.

    That being said, the language used by the manufacturers is not just marketing filler, it could very well have cost me the lens.

  • Aaron

    I thought plastic/metal mounts were the flange that get’s pushed into the lens mount and twisted (i.e. the flanges).

  • Leo Tam

    It’s like everyone’s other favorite argument: PC vs Magnesium bodies
    The chassis is a metal/composite- the exterior doesn’t really matter
    Leica M’s (well M1-M6, not sure about the M7 and up) have a metal mount on a metal body, but the way it’s mounted, you can give the front of the camera a nice firm squeeze and throw the focus off a bit

  • Andrew

    I agree fully that internet “experts” run wild when incidents like the 12-40mm happen and usually have very liitle facts or knowledge to back up their assumptions. However whether its plastic or metal there still seems to be a potential design flaw to the 12-40mm mount which shouldn’t be discounted due to some “experts” going off on a tangent. If the claims of breakage with little force are true then perhaps its a poor choice or bad batch of plastic, or too short or over tightened screws. Also do some lenses mounts provide more lateral support than others (in other words don’t fully rely on the screws only to take any side loads?)

  • BH

    Interesting post, thanks Roger. There seems to be a pervasive idea that plastic = cheap and metal = quality. I suppose this is rooted in the idea that things used to be made to a higher standard, and fewer things were plastic circa half a century ago. “My M3 still works perfectly sixty years later while my Canon plastic fantastic broke after a year!”

    I’m no engineer, but I suppose there is a ton of research into why using plastic may be *better* than metal. Perhaps someone reading this could elaborate?

  • Max

    No one did this yet ? Oh well…..

    http://www.youtube.com/watch?v=PSxihhBzCjk

  • Roger Cicala

    Carvac, I don’t disagree – but the online screaming has been that the Olympus 12-40 has a plastic mount and that is unacceptable. It’s bayonet is, of course, obviously metal but the screws go into a plastic mount. This has been what all the fuss is about.

  • CarVac

    Roger, you missed the point that most people never take their lenses apart, and thus never ever refer to the internals as “the mount”.

    Some of the claims you cited would certainly be truer if you evaluate them this way.

    Most m43 lenses have metal bayonets.
    All “professional quality” lenses have metal bayonets.
    [the third one is false]
    [the fourth one is false]
    Plastic bayonets break (or wear out) more often than metal bayonets. [I don’t know if this is true or not, but it’s certainly plausible]

  • Roger Cicala

    The flanges that attach to the camera are always metal except in a very few, very odd lenses. Generally they are referred to as the bayonet mount. What the screws from that ring attach to are what we are discussing today.

    The actual lens optical elements attach to the mounting flange via either a plastic or metal mount.

  • ahsanford

    I rescind my prior question. So you are defining ‘lens mount’ as the **supports for the terminal mating feature** that attaches to the camera and not the terminal mating feature itself?

    Most I’ve seen online (perhaps in ignorance) would define the lens mount as that terminal mating feature, but regardless, it’s fascinating to see what’s *behind* that feature. I own the Canon 24-70 F/2.8L I you reference, and I’m fairly certain I could use it (attached to a body) as a tool to forge other metal objects with. It’s a beastly piece of kit.

    Thanks for the good read! Fascinating as always.

  • ahsanford

    I didn’t know that Canon’s 35L had a plastic mount.

    I’ve rented one from you that is metal, and I thought there was only that original design for the 35 F/1.4L USM — was this a running design change? did they start as plastic and then switch to metal?

    Just curious.

  • Bruce Rubenstein

    I think when most people refer to a metal/plastic mount, they are referring to the material used for the bayonet, and not what the bayonet is attached to.

    Besides making repair of the lens simpler, a sacrificial, designed break point also helps to keep the camera body from being damaged.

    FYI, one of the folks who had their 12-40/2.8 break was sent a new lens that appears to have been shipped directly from Olympus. This was interesting, because Olympus USA outsourced their camera repair to Precision Camera in CT. It looks like Olympus is looking into what ever the issue (breaking from minimal impact) is with the lens. I personally suspect that the breakage is not due to an inherent design flaw in the lens, but a non-conforming part, or assembly problem.

  • Roger Cicala

    Ryan, we don’t see it very frequently, but when we do it seems to be more about wear on the metal mount itself: the flanges can get a bit loose but the mount itself almost never.

  • Ryan

    Do you see any signs of metal or plastic wearing out from many lens swaps? Do either get looser over time?

  • PaulB

    Roger

    Thanks for such a well written article that goes to the point of expectations. Though going one step further even the terms plastic and metal are also generic and prone assumptions and false expectations, based on where they are used.

    From an engineering sense unless we are told the type of metal or plastic and it series, or alloy, number, and how it was formed we simply don’t know what we are getting. For example an aluminum part made from a 7075-T6 forging will be a lot stronger than the same part made from a 1000 series casting; though both may be strong enough for a given use. We have the same situation in the world of plastics with nylon based plastics being different than polycarbonate, but both may be adequate for a given use.

    Of course, what I have listed above it still not enough information to know anything. Which brings us back to your point, the marketing people tell us what they want and we decide what we think it means.

    PaulB

  • In theory, plastic mounts might be better, worse, or no different than metal as far as reliability goes. There are logical arguments for each.

    Gun forums have the same arguments: at some point (I think in the ’80s), manufacturers like Glock began making guns from plastics instead of metal. This caused all sorts of hysteria among gun nuts, and it continues to this day despite the lack of evidence that guns with some plastic parts are any worse than guns without them. The guns with plastic parts are certainly lighter, however.

    And guns obviously undergo a lot more stress than cameras or lenses.

  • Rick

    Hi guys,

    Another kudos for a really cool article. I think this is probably the most informative piece of article that I’ve read in all of 2013! Yes, it goes to show how little deference the self-claimed “internet authorities” deserve.

    Happy new year!
    Rick

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