[pacerr]

. . . remember the REALLY good old days, when lenses were made of bark?

But those made of solid, hand rubbed ebony and walnut were far superior to those made of cheap birch and fir bark that attracted dry rot and termites.

H2

[tokyoso]

I'm liking it because it matches the color of my camera body.

[reeftool]

I think the bigger issue in the metal vs plastic debate is the life expectancy and durability. I don't know if all these 18-55 kit lenses will be kicking around in 30 years like the kit lenses of old, like the Takumar 50's and 55's that were sold with the Spotmatics. I've had a lot of good shots from my 18-55. It doesn't deserve the bashing it gets sometimes. I can remember back in the 70's that the Takumar 55/f2 got bashed a lot in some magazine reviews for no other reason than it was f2. It sells quite cheaper than the faster versions even though the optics are the same. It just has a different aperture ring that doesn't open as far. Even today, after all these years, it is one of my most used lenses.

[Ira]

They still are. Where do you think is the source of the cellulose used in optical plastics and resins? That's right, tree bark.

So we're all responsible here for global warming then.

[TaoMaas]

I think the bigger issue in the metal vs plastic debate is the life expectancy and durability.

I think you're right. What I'd always heard is that plastic lenses lose their ability to hold the lens elements in alignment quicker than metal lenses. I'd never owned a plastic lens until recently, so I've never had a chance to test that theory. However, I have to say that the used FA 28-80 that I picked up a few months ago still seems to be going strong despite its age.

[Pentaxor]

I think you're right. What I'd always heard is that plastic lenses lose their ability to hold the lens elements in alignment quicker than metal lenses. I'd never owned a plastic lens until recently, so I've never had a chance to test that theory. However, I have to say that the used FA 28-80 that I picked up a few months ago still seems to be going strong despite its age.

I believe that is a wrong thinking about plastic as being brittle. as I had mentioned before, it depends on what particular plastic is used. there are pressure, heat, water, fire and any other elemental stress that could cause misalignment and breakage are avoided by making or producing a material with more fused and compact atoms.

[reeftool]

Well, in 30 years we will have to dig up this thread and see if our plastic 18-55 kit lenses are still usable, assuming they have been "used" on a continual basis. The only way this issue will be truly resolved is to wait and see how long they last. I'll be 90 so I probably won't remember. Some plastics have a life span of centuries according to the environmentalists. Like any other product, it is going to be the choice of material and build quality that determines how good it is. I had a 3/4 inch drive impact wrench fail after about 5 years of heavy truck shop use. It was very lightweight, mostly composite plastics. It was the metal parts that failed. The plastic housing is as good as new (dirty but intact). It is always the friction in moving parts that wear out. Metals wear, a well known fact. Saying a metal lens is "better" than a plastic lens without knowing the quality of the materials and skill of the machinists doesn't make sense. A cheap metal lens made with less skilled labor (a lot of crap in the 60's and 70's) will probably be of a poorer quality than a plastic lens that is mostly made in an automated factory and just "assembled" on a line.

[jct us101]

Well, in 30 years we will have to dig up this thread and see if our plastic 18-55 kit lenses are still usable, assuming they have been "used" on a continual basis. The only way this issue will be truly resolved is to wait and see how long they last. I'll be 90 so I probably won't remember. Some plastics have a life span of centuries according to the environmentalists. Like any other product, it is going to be the choice of material and build quality that determines how good it is. I had a 3/4 inch drive impact wrench fail after about 5 years of heavy truck shop use. It was very lightweight, mostly composite plastics. It was the metal parts that failed. The plastic housing is as good as new (dirty but intact). It is always the friction in moving parts that wear out. Metals wear, a well known fact. Saying a metal lens is "better" than a plastic lens without knowing the quality of the materials and skill of the machinists doesn't make sense. A cheap metal lens made with less skilled labor (a lot of crap in the 60's and 70's) will probably be of a poorer quality than a plastic lens that is mostly made in an automated factory and just "assembled" on a line.

Well some of the Pentax lenses that were produced 30 years ago were plastic, just on a lot lower level. How are those ones doing?

[RioRico]

Well some of the Pentax lenses that were produced 30 years ago were plastic, just on a lot lower level. How are those ones doing?

I don't think Pentax made plastic lenses 30 years ago. Plastic rings, yes, on top of metal barrels. But the oldest Plastic Pentax lens I have is a SMC-A 35-80, a kit lens on my ZX-M (1997). Sadly, it's a POS -- optical plastic, cruddy optics, but nothing wrong mechanically. And sadly, a few metal-body glass-element Pentax lenses are in the POS category too. (I know, I have a couple. Ech.) Was Pentax making plastic lenses before the cheaper A-series? We know that modern zooms often have optical-plastic elements internally. Any signs of those deteriorating?

Well now, early one day in the month of May
I went down to the beach
There were cuties and beauties in little bathin' suities
And all of them within my reach
Now a 38-24-36 miss just happened to be walkin' my way
I said, "Please don't think me nervy but you look so very curvy
Tell me how you got that way"

She said, "It's plastic!
Oh, yes, it's plastic!
It's as pretty as can be,
But you know that it ain't me
Because it's plastic!
I said, it's plastic!"
Everything's gonna be plastic by and by!
--Shel Silverstein

[jct us101]

I don't think Pentax made plastic lenses 30 years ago. Plastic rings, yes, on top of metal barrels. But the oldest Plastic Pentax lens I have is a SMC-A 35-80, a kit lens on my ZX-M (1997). Sadly, it's a POS -- optical plastic, cruddy optics, but nothing wrong mechanically. And sadly, a few metal-body glass-element Pentax lenses are in the POS category too. (I know, I have a couple. Ech.) Was Pentax making plastic lenses before the cheaper A-series? We know that modern zooms often have optical-plastic elements internally. Any signs of those deteriorating?

Well now, early one day in the month of May
I went down to the beach
There were cuties and beauties in little bathin' suities
And all of them within my reach
Now a 38-24-36 miss just happened to be walkin' my way
I said, "Please don't think me nervy but you look so very curvy
Tell me how you got that way"

She said, "It's plastic!
Oh, yes, it's plastic!
It's as pretty as can be,
But you know that it ain't me
Because it's plastic!
I said, it's plastic!"
Everything's gonna be plastic by and by!
--Shel Silverstein

As a side note, first, I would like to say that I think it's kind of funny that you keep posting song lyrics after your posts, such an easy way to defeat that new algorithm for the contest. Maybe I'll start trying that instead of actually making full size posts like I've been trying to (not a stab at you, but at the contest, mostly, since your posts already have a lot in them already).

I thought that all of the A series lenses were made of metal though, at least the ones that I know of were. I was thinking of the oldest of the FA series that had autofocus and such. I'm also a bit curious to know if the AF has deteriorated with those lenses (did they have a built in motor back then, or was it still in the camera then too?) or things like the zooming and such. I think that's the only real fair comparison that can be made to the lenses that are being made now fairly cheaply.

[séamuis]

As a side note, first, I would like to say that I think it's kind of funny that you keep posting song lyrics after your posts, such an easy way to defeat that new algorithm for the contest. Maybe I'll start trying that instead of actually making full size posts like I've been trying to (not a stab at you, but at the contest, mostly, since your posts already have a lot in them already).

I thought that all of the A series lenses were made of metal though, at least the ones that I know of were. I was thinking of the oldest of the FA series that had autofocus and such. I'm also a bit curious to know if the AF has deteriorated with those lenses (did they have a built in motor back then, or was it still in the camera then too?) or things like the zooming and such. I think that's the only real fair comparison that can be made to the lenses that are being made now fairly cheaply.

the early A series and im sure the A*'s were metal bodied, but some later A series were plastic bodied. this heavily included the 'kit' A 50mm f2, common on the later (also plastic bodied) k1000's

[jct us101]

the early A series and im sure the A*'s were metal bodied, but some later A series were plastic bodied. this heavily included the 'kit' A 50mm f2, common on the later (also plastic bodied) k1000's

Were all of the A 50mm f/2s plastic? I had one but I thought that it was metal, it sure felt sturdy enough to be metal. I think there might have been one or two plastic pieces on it, but it sure felt heavy enough to be all metal though.

[séamuis]

Were all of the A 50mm f/2s plastic? I had one but I thought that it was metal, it sure felt sturdy enough to be metal. I think there might have been one or two plastic pieces on it, but it sure felt heavy enough to be all metal though.

no, not all. but the thing is, that you cant count all A series lenses as being '30 years old' because pentax kept making these lenses for a very long time, from when metal was common through to the era of all plastic lenses. (this long manufacture time was due to the long run of the K1000 among other things)

[RioRico]

As a side note, first, I would like to say that I think it's kind of funny that you keep posting song lyrics after your posts, such an easy way to defeat that new algorithm for the contest. Maybe I'll start trying that instead of actually making full size posts like I've been trying to (not a stab at you, but at the contest, mostly, since your posts already have a lot in them already).

I think that's the first full verse and chorus I've added, and I would have added that before the contest if I'd found it then. It just seems so appropriate here. "Everything's gonna be plastic by and by!" Mostly I'll pick out short quotes as tags, and I've been doing THAT since before the contest too. I never actually entered the contest. I'm just trying to continue with my obsession of writing content-filled posts, with waves of insanity and exegesis as needed. (You should see how much I write, then edit out.)

But back to plastic (not silicone). One of my favorite old lenses is a (Schneider) Isco-Gottingen Weston 35/2.8 that may have been one of the first German lenses to have a plastic housing around the metal body. It was criticized when released for being plastic (and RED plastic at that); but its superb optics make up for the cosmetic shortcoming. And it's one of those lenses designed to be thread-reversed or bellows-mounted for macro work, with a threaded jack on the side to take a control cable for aperture stop-down. A real class act.

A plastic German lens! And not Porst! Who could imagine... ???