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01-13-2013, 12:48 PM   #1
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Plastic in Pentax Lenses?

Greetings All!

I'm new here, and maybe this question has been answered before, although a quick search of similar threads turned up nothing.

I've heard that there is a substantial amount of plastic contained in today's Pentax's DA lenses. Obviously, the outside of the lenses are plastic (except, perhaps for the mounting), but I'm curious as to how much of what (glass vs. plastic) is actually inside.

I'm from the "old school" of Pentax. My first Pentax camera was an Asahi Pentax Spotmatic (with a matching 50 mm 1-1.4 lens) which was a hand-me-down from my Dad back in 1969. When he passed on in 1994, I then inherited his Pentax ES-II and all of his Takumar screw mount lenses (50 mm 1:1.4, 135 mm and 28 mm) that went with it I still have (and occasionally use) that camera and many of those lenses even today when I shoot a roll or two of film.

Over the years, I've added to my Pentax collection with 2 K-mount ME Supers (along with matching 135 mm and 28 mm lenses), which, again, I still have...and use. I've since gone digital with a couple of K-100ds, a K-10 and a K-20 to boot.

Clearly, the older Takumar and SMC Pentax lenses seem to be quite well made...a bit heavy....but solid lenses nonetheless.

I'm now starting to explore matching some of these older Takumar lenses to my newer K-10 and K-20 camera bodies. I'm looking forward to comparing the old and new glass (plastic?) on these newer digital cameras.

Any info anyone could pass along to me about mating these older lenses (beyond needing an adapter for the screw mounts) to newer equipment (as well as your take on the glass vs. plastic question) would be most appreciated!

Cheers!


Last edited by KB1SFVE3; 01-13-2013 at 04:00 PM.
01-13-2013, 12:55 PM   #2
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QuoteOriginally posted by KB1SFVE3 Quote
Greetings All!

I'm new here, and maybe this question has been answered before, although a quick search of similar threads turned up nothing.

I've heard that there is a substantial amount of plastic contained in today's Pentax's DA lenses. Obviously, the outside of the lenses are plastic (except, perhaps for the mounting), but I'm curious as to how much of what (glass vs. plastic) is actually inside.

I'm from the "old school" of Pentax. My first Pentax camera was an Asahi Pentax Spotmatic (with a matching 50 mm 1-1.4 lens) which was a hand-me-down from my Dad back in 1969. When he passed on in 1994, I then inherited his Pentax ES-II and all of those Takumar screw mount lenses (50 mm 1:1.4, 135 mm and 28 mm). I still have (and occasionally use) that camera and many of those lenses even today when I shoot a roll or two of film.

Over the years, I've added to my Pentax collection with 2 K-mount ME Supers (along with matching 135 mm and 28 mm lenses), which, again, I still have...and use. I've since gone digital with a couple of K-100ds, a K-10 and a K-20 to boot.

Clearly, the older Takumar and SMC Pentax lenses seem to be quite well made...a bit heavy....but solid lenses nonetheless.

I'm now starting to explore matching some of these older Takumar lenses to my newer K-10 and K-20 camera bodies. I'm looking forward to comparing the old and new glass (plastic?) on these newer digital cameras.

Any info anyone could pass along to me about mating these older lenses (beyond needing an adapter for the screw mounts) to newer equipment (and/ your take on the glass vs. plastic question) would be most appreciated!

Cheers!
Cheaper lenses have their casings made entirely of plastic (like the DA 35mm or DA 50mm, which even have a plastic mount), while more expensive ones, such as the FA limiteds or the D FA 100mm WR, have no plastic in them AFAIK. I would expect the exterior to be indicative of what's on the inside also

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01-13-2013, 01:18 PM   #3
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I sincerely doubt the actual lens elements are made out of plastic materials, except maybe aspherical and molded lenses.
01-13-2013, 01:18 PM   #4
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QuoteOriginally posted by KB1SFVE3 Quote
I'm now starting to explore matching some of these older Takumar lenses to my newer K-10 and K-20 camera bodies. I'm looking forward to comparing the old and new glass (plastic?) on these newer digital cameras.
It *almost* sounds like you are asking not just about the structural and mechanical elements, but also the optical elements. I can assure you that all the glass parts are still glass -- no such thing as a plastic optical element that isn't a toy. Although people seem to think plastic bad/metal good, I don't think there is any evidence that modern lenses using plastic are to be feared...

01-13-2013, 01:24 PM   #5
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I love my Takumars and they work very nicely on new bodies. There is a different look to them, perhaps not as 'refined' or 'sterile' as new lenses, they seem to have more character. That also means they have more aberrations in some cases.

Look here for information on using manual lenses on new bodies: https://www.pentaxforums.com/forums/pentax-beginners-corner-q/110658-using-ma...x-dslrs-f.html

Look here for the Takumar Club: https://www.pentaxforums.com/forums/lens-clubs/31601-takumar-club.html

If your question is are the lens elements inside glass or plastic as far as I know they are all glass. Plastic is used in some places: body shell, mount, etc but not in the 'glass' itself. And if you want to see the same quality build of the Takumars try one of the Limited lenses. Different style, different materials, but same workmanship. A real pleasure to use.
01-13-2013, 02:00 PM   #6
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Polycarbonate is a well established material. Some of the most reliable handguns in the world have their frames made from it. I have no problem with either a Camera body or a Lens body (obviously not the glass) made from that.

Its tough.

01-13-2013, 02:06 PM   #7
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Could we please leave guns out of the discussion? Thanks.

Last edited by John Poirier; 01-13-2013 at 02:06 PM. Reason: spelling
01-13-2013, 02:15 PM   #8
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QuoteOriginally posted by John Poirier Quote
Could we please leave guns out of the discussion? Thanks.
Sorry, I was just making a point of todays "Plastic" materials and why they are quite durable.

01-13-2013, 02:24 PM   #9
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QuoteOriginally posted by Corto-PA Quote
Sorry, I was just making a point of todays "Plastic" materials and why they are quite durable.
Then you could have pointed out that football helmets and bullet-proof "glass" are made of polycarbonate...My eye glasses are made of polycarbonate.

Lexan - Wikipedia, the free encyclopedia
01-13-2013, 02:28 PM - 3 Likes   #10
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QuoteOriginally posted by boriscleto Quote
Then you could have pointed out that football helmets and bullet-proof "glass" are made of polycarbonate...My eye glasses are made of polycarbonate.

Lexan - Wikipedia, the free encyclopedia
Or guns. What's with the thought police? Guns need to be made tough, so it is a perfectly valid example. We are not allowed to speak of them now? Sheesh.

Also tough: Nalgene bottles. More acceptable?
01-13-2013, 02:31 PM   #11
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QuoteOriginally posted by boriscleto Quote
Then you could have pointed out that football helmets and bullet-proof "glass" are made of polycarbonate...My eye glasses are made of polycarbonate.

Lexan - Wikipedia, the free encyclopedia
You are right and I apologize if I offended anybody, I simply related to something I know about.

I have been a freehand Pistol target shooter for years, And I do use Glasses made of Polycarbonate when I compete.
01-13-2013, 02:35 PM   #12
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QuoteOriginally posted by jatrax Quote
If your question is are the lens elements inside glass or plastic as far as I know they are all glass.
Hybrid aspheric lenses have a layer of plastic added to a spherical glass element.


Note the first (left hand) element on the DA 15 Ltd diagram from Boz Dimitrov's site:

01-13-2013, 02:45 PM   #13
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QuoteOriginally posted by KB1SFVE3 Quote
Obviously, the outside of the lenses are plastic (except, perhaps for the mounting), but I'm curious as to how much of what (glass vs. plastic) is actually inside.

I'm from the "old school" of Pentax. My first Pentax camera was an Asahi Pentax Spotmatic (with a matching 50 mm 1-1.4 lens) which was a hand-me-down from my Dad back in 1969

your take on the glass vs. plastic question) would be most appreciated!
I have an M42 35/2.8 ISCO lens from the 1960s which has a plastic body (but metal screw mount).

It's still mechanically sound to this day.
01-13-2013, 02:46 PM   #14
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QuoteOriginally posted by Adam Quote
Cheaper lenses are made entirely of plastic
Absolutly not true
The electronic contacts aren't made of plastic and the gears and the shafts of the AF is also off metal most likely
01-13-2013, 02:50 PM   #15
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QuoteOriginally posted by Anvh Quote
Absolutly not true
The electronic contacts aren't made of plastic and the gears and the shafts of the AF is also off metal most likely
I've always wanted to make a video where a modern lens is dismantled, so I think we'll go ahead and find this out empirically I'd expect a lot of the gears in a small lens to be made of plastic, though.

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