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Are Metal Mounts Better Than Plastic?
« on: January 04, 2014, 09:11:26 AM »
The following article is by Roger Cicala and Aaron Closz from LensRentals.com

Assumptions, Expectations, and Plastic Mounts 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 that the lens mount attaches to.

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

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 lens mount attaches. The 3 screws still in place attach this plastic piece to the next plastic piece in the lens barrel.

Panasonic-Leica 45mm. The 4 empty plastic holes are where the lens mount 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 lens mount attach.

Sony 50mm f/1.8. The 4 hollow plastic posts are where the screws from the lens mount 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 lens mount attaches.

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

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.

Common mount with empty plastic holes that attach the lens mount, and screws remaining in holes attaching this to the next barrel piece.

Common mount with empty plastic holes that attach the lens mount, 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.

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

Tape over access holes in 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

« Last Edit: January 04, 2014, 09:21:14 AM by Canon Rumors »
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Are Metal Mounts Better Than Plastic?
« on: January 04, 2014, 09:11:26 AM »

Quasimodo

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Re: Are Metal Mounts Better Than Plastic?
« Reply #1 on: January 04, 2014, 09:25:13 AM »
I always enjoy reading his articles, and this one had quite a bit of humor in it as well :)

This coming from a guy who works with marketing, and is the first to fall for marketing catch words :)
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Re: Are Metal Mounts Better Than Plastic?
« Reply #2 on: January 04, 2014, 09:29:05 AM »
I previously owned the 24-70 f/2.8L. I could have sworn it had a metal mount. Am I crazy?
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Re: Are Metal Mounts Better Than Plastic?
« Reply #3 on: January 04, 2014, 09:41:52 AM »
How dare you clutter an emotional issue with facts!!!!  LOL  ;D

Awesome article.  I can't wait for a camera and lens to come with luxurious "Corinthian Leather" or "Quasi-Optically Precise" engineering!   ::)  LOL
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Efka76

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Re: Are Metal Mounts Better Than Plastic?
« Reply #4 on: January 04, 2014, 09:42:15 AM »
Very good article. However, now when I know the truth, I am really disappointed. The most disappointing fact is that photographic companies are charging for "professional grade" products really high and people assume that they even could use them during rain, however, reality is really different.
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Jim Saunders

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Re: Are Metal Mounts Better Than Plastic?
« Reply #5 on: January 04, 2014, 10:26:26 AM »
I previously owned the 24-70 f/2.8L. I could have sworn it had a metal mount. Am I crazy?

The bayonet fitting is metal, but I also learned from this that it is screwed to plastic parts.

Jim
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Re: Are Metal Mounts Better Than Plastic?
« Reply #6 on: January 04, 2014, 10:26:56 AM »
I think Rogers's definition of a plastic vs. a metal mount differs from how most people think about those terms.  For most of us, we're talking about the bayonet parts - the 'teeth' that lock into the mount on the camera. 

 

The EF-S 18-55 on the left has a 'plastic mount', the EF 17-40L on the right has a 'metal mount'.  Very few of us disassemble lenses, so we have no idea what's behind that mount surface.  Roger is talking about how the screws that that attach that visible surface piece to the lens are connected - do those screws go into metal screw-holes that are attached to the frame of the lens, or are the screw-holes plastic?

'Plastic' can be quite strong, so for a 'light' lens (most lenses under 100mm, with the exception of the 'magic cannonball' 85L), I agree with Roger that I wouldn't expect any issues, and 'professional' could apply.  However, for the bayonet 'teeth' of the mount, plastic wears down more easily than metal (vs. the screw-holes, which aren't subjected to routine 'wear'). That means a lens with a plastic mount (as I'd say is the common definition pictured above, not Rogers's use of the term), would be able to tolerate fewer mount/unmount cycles than a lens with metal bayonet teeth.  Since a professional lens would be expected to last years and most 'pros' own several lenses and change them frequently, it makes sense to associate a metal mount (as pictured above, regardless of how it's screwed in) with 'professional' build.
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Re: Are Metal Mounts Better Than Plastic?
« Reply #6 on: January 04, 2014, 10:26:56 AM »

Don Haines

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Re: Are Metal Mounts Better Than Plastic?
« Reply #7 on: January 04, 2014, 10:44:29 AM »
Plastic comes in many forms and grades... If it is the right material for the job, then it is the right material.... In some cases, plastic is superior to metal, in other places it is inferior.

You can not treat all plastics the same. Just like tin is different from titanium, so are the plastic parts of your lens different from a child's sippy cup.
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infared

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Re: Are Metal Mounts Better Than Plastic?
« Reply #8 on: January 04, 2014, 10:47:16 AM »
Roger's articles are always GREAT...he backs them with facts and I always learn!
I have an extensive Canon FF system and an extensive MFT system (10 lenses for each)...
I do a lot of research (ALWAYS) before I buy.  I was looking into the Olympus 12-40 zoom that Roger mentions in his article.   The marketing stated "PRO"  ....which I laugh at, too.  ....BUT...if you go to the Olympus website and read some of the finer print (which I did), about the lens on the product page, Olympus states: " this lens features all metallic construction ".  Link to page here: http://www.getolympus.com/us/en/lenses/pen-omd/m-zuiko-digital-ed-12-40mm-f2-8-pro.html
Now, I would consider myself a relatively intelligent guy with a ton of experience in photography.  I do not think that plastic is a bad thing in "pro" (LOL) lens design. ( I own a Canon 100mm Macro f/2.8L IS ($1000...made of plastic, incredible lens).  So here is my question...If the manufacturer states "the lens features all metallic construction", would I expect that my metal lens mount is held in place by three plastic support rods...which are a main part of the construction of the lens??? I accuse Olympus of lying here. Outright. (mind you...I own two of their cameras and many of their lenses and love & enjoy their products).   They need to change the data on their product page.  That verbiage is not just misleading. It is not truthful. Period.
I suspect that the design may be a little lacking regarding the weight of the lens and it may be too much for the mount design and/or there was/is some manufacturing problem here... who knows.
I have not bought the lens as it is $1000...I think there "may" be some kind of problem and Olympus has not addressed it.
All respect to Roger...but I think that something is "up" with this lens, perhaps.  Maybe not..but there are alternative lenses to choose from that have not been exhibiting "this" issue. LOL.
Of course...the plastic mounts are far easier to replace/repair (thanks Roger...I did not know that!)...so in the end...maybe it doesn't matter.  Also..we do not know "exactly" how these lenses on the internet were damaged. People do lie, or are completely unaware of what actually happened to their lens and why it got damaged.  :-)

I recently went to a photo workshop where 20 "photographers" met in a parking lot. I would say that most were not "casual" photographers.  In a 10 minute span I witnessed one person dropping their camera on the asphalt, and another knocking their camera (on a tripod) over and it slammed on concrete. We had not begun shooting yet.  Perhaps those individuals consider that "normal" wear-n-tear....I do not know????..so I guess I should take everything with a grain of salt.  :o
« Last Edit: January 04, 2014, 11:37:46 AM by infared »
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Re: Are Metal Mounts Better Than Plastic?
« Reply #9 on: January 04, 2014, 10:51:59 AM »
Neuro's post is exactly what I was thinking. When i hear of people on the the net talking about metal mount, i'm usually thinking of the outside part of the lens that physically touches the camera body, not the inside of the lens that this metal piece attaches to. This is echoed by terms like M-Mount, R-Mount, E-Mount(excuse me, spending a lot of time in RF land these days.)
However, I really enjoyed this article, and I would never argue about camera terms with someone who obviously knows so much more about the subject than I will ever know
I do however also believe that modern plastics are often superior to metals in many situations, and I also agree with the statement in the article that plastic simply breaks when dropped while metal twists and creates alignment issues.
I was also unaware that this was such a heated issue as of late? is there really that much of a controversy going on in Olympus land?
All in all a really interesting and fun article to read.
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Achim

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Re: Are Metal Mounts Better Than Plastic?
« Reply #10 on: January 04, 2014, 11:47:51 AM »
In the late 70's Canon switched its FD mount from the old design with a coupling ring to the "standard" bayonet. And they made the first "plastic" lenses e.g. the 35...70mm/3.5-4.5. The magazines were full of discussions why this would be the death of Canon and a shame - while Canon said those "plastics" would be more precise and durable than metal...

My 35...70 (bought in 81) still works perfectly (and my other FDs too!) though I didn't really kept an eye to them while shooting outdoors... A full metal Tokina isn't working for a long time now and my "full metal" german Exakta from the late 60's is working but not smoothly...

And the brakes of some super sport cars are also made of "plastics" - or isn't carbon fibre not a kind of "plastic"???? :) :)

aldvan

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Re: Are Metal Mounts Better Than Plastic?
« Reply #11 on: January 04, 2014, 11:51:30 AM »
As Infrared reminds, the 100mm Macro f/2.8L IS has a plastic frame. It is not only one of the sturdiest lens on the market, but also deliciously tight,  light and pleasant to the touch. Furthemore, it is insensitive to paint scratches and abrasion as, on the contrary, it is a big white.
I want to add something about pro camera bodies. I own a 5D MkII and a 1Ds MkIII, both made of magnesium and black painted. The first one is light and compact enough to be exempted to damages due to small impacts, the second one, when hosting a big lens as a 100-400, is exposed to any sort of hi cinetic impacts when hanging to your shoulder strap and to paint abrasion due to its weight oscillating against your body.
I can understand that the marketing would have some reservation to sell a 8000$ plastic body, but I'm sure that, chosing the right, and expensive, kind of resin, the result would be sturdier and lighter. And there is always the chance to propose with all the whistles and bells a beautiful carbon fiber body...

AlanF

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Re: Are Metal Mounts Better Than Plastic?
« Reply #12 on: January 04, 2014, 12:17:47 PM »
In the late 70's Canon switched its FD mount from the old design with a coupling ring to the "standard" bayonet. And they made the first "plastic" lenses e.g. the 35...70mm/3.5-4.5. The magazines were full of discussions why this would be the death of Canon and a shame - while Canon said those "plastics" would be more precise and durable than metal...

My 35...70 (bought in 81) still works perfectly (and my other FDs too!) though I didn't really kept an eye to them while shooting outdoors... A full metal Tokina isn't working for a long time now and my "full metal" german Exakta from the late 60's is working but not smoothly...

And the brakes of some super sport cars are also made of "plastics" - or isn't carbon fibre not a kind of "plastic"???? :) :)

The etymology of "brake" is that it comes from Middle Dutch braeke, related to breken to break. Therefore, this is one example where plastics break!
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Re: Are Metal Mounts Better Than Plastic?
« Reply #12 on: January 04, 2014, 12:17:47 PM »

johnhenry

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Re: Are Metal Mounts Better Than Plastic?
« Reply #13 on: January 04, 2014, 12:21:02 PM »
Metal construction is certainly heavier than plastic, as I can attest from owning the 28mm f/2.0 Zeiss, 35mm Zeiss, PC, 85mm f/1.2 Zeiss, 105 Zeiss UV Sonnar, 200mm f/2 Sonnar and 200mm f/1.8 Canon lenses.

So far, the only service has been to replace a wore helicoil focuser on the 28mm, one of my favorite lenses.

Leica and Zeiss both felt that metal was the ONLY way to build lenses, at least from a reliability standpoint.

Most people will never get to the point in the use of their equipment where they will test the strength of the mount etc. More likely is damage to optics and electronic components. Beofre that happens, the lens will probably be sold or retired from service



 

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Re: Are Metal Mounts Better Than Plastic?
« Reply #14 on: January 04, 2014, 12:26:44 PM »
My "weather sealed" Canon Rebel.

A couple years ago I slipped on some rocks and fell into a river with my Rebel Xsi and canon 10-22mm lens. The water was neck high, so lucky I'm still here to post things, but my camera was dead, and my lens was full of water inside and out.   I took the lens off, the mirror was wet, so I wrote it off.  A couple weeks later, I went to toss the equipment. just for the hell of it, I put a battery in the Rebel, turned it on, and it worked perfectly.  I paid about 50.00 to replace the focus screen and clean the sensor/mirror.  5 years later, the Rebel is still my backup. 

I would not recommend "trying this at home"...but it shows that sometimes even the low end of the equipment line can be like a Timex(for those who don't remember...''takes a licking and keeps on ticking")

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Re: Are Metal Mounts Better Than Plastic?
« Reply #14 on: January 04, 2014, 12:26:44 PM »