[Ian Stuart Forsyth]

So everytime people hear abour cameras, lenses that made of plastic material
most always complain
"Oh pls
Plastic is cheap, toy-ish
Plastic is not serious
Plastic isn't durable and will fall-apart soon

overall plastic is a joke, so deal-breaker"

what do you think? is plastic really that bad?

Its funny how people think that plastics are soo bad and that they are prone to failure. When people think of plastic being used in lenses they feel this as somehow reducing the quality built into the lense.

Now if we look at how successful pentax has been with their K7 thru to K1 line of cameras and how little of a problem they have had with those series of cameras, many may be in for a surprise to find out that the major part of the bodies chassis that transfers the load of the lens to the rest of the camera body is composed of plastic

With how little of a problem we have and how rugged they camera is thought of as being from how people think it is all metal construction ,knowing that a major part of the chassis is built from plastic does this make that series of camera any lower quality

[gofour3]

There are many types of plastics and it can be very durable if designed right. But it seems like the biggest motivation these days to use plasic is to cut cost, not to improve durability.

I have not had that many issues with plastics on my cameras or lenses, but the plastic cover on my K10D have cracked and a plastic part inside my MZ5n broke which killed the camera.

Yep very true. That's the main problem with the A50/1.7 & A50/2 is the plastic aperture ring assembly that jams. Or the PZ/Z bodies plastic bottom (cracking problems) and the last "made in China" plastic junk K1000's.

Phil.

[reh321]

Yep very true. That's the main problem with the A50/1.7 & A50/2 is the plastic aperture ring assembly that jams. Or the PZ/Z bodies plastic bottom (cracking problems) and the last "made in China" plastic junk K1000's.

The aperture ring of my A50/1.7 developed a "hitch", a place I had to carefully move past, shortly after it was kitted with my Super Program in 1983, but I used that combination for eleven years When I got my K-30 and came back to Pentax three years ago, I started using that lens again. Recently I had to "retire" that lens; the aperture ring still had that "hitch" that I still had to work my way past, but the lubrication seems to have dried up after 35 years, and focusing to the infinity end was becoming an issue, so I'm not convinced "plastics" were that bad of an issue with the "A" lenses.

[gofour3]

so I'm not convinced "plastics" were that bad of an issue with the "A" lenses.

It's just those two 50mm "A Series" lenses, all the rest have the older style metal aperture ring assemblies. I sent my A50/1.7 to Eric for a CLA, as the aperture ring was very stiff.
He said there is not much he could do as Pentax used plastic aperture parts on those "budget" 50mm standard lenses, which basically ruined an optically very good lens. If Pentax had used a metal aperture ring assembly, then the A50/1.7 & A50/2 would have been the same as the rest of the A Series lenses. Pentax was just being cheap and tried to save a few dollars on the cost of a couple lenses, unfortunately it back fired.

Phil.

[reh321]

It's just those two 50mm "A Series" lenses, all the rest have the older style metal aperture ring assemblies. I sent my A50/1.7 to Eric for a CLA, as the aperture ring was very stiff.
He said there is not much he could do as Pentax used plastic aperture parts on those "budget" 50mm standard lenses, which basically ruined an optically very good lens. If Pentax had used a metal aperture ring assembly, then the A50/1.7 & A50/2 would have been the same as the rest of the A Series lenses. Pentax was just being cheap and tried to save a few dollars on the cost of a couple lenses, unfortunately it back fired.

I used mine consistently for eleven years .... I hardly think that is a "backfire". Mine was optically very good and it most certainly was not ruined - at least as long as the lubrication held up!!!

[victormeldrew]

It's interesting how many people say that plastic mounts and barrels 'seem fragile' or 'feels flimsy' but nobody has said 'mine broke'. I wonder what the comparitive failure rates are...I bet an impact that would break a plastic mount would bend a metal one, and both will need replacing regardless.


The A 50 is a peculiar case...yes there is a plastic part that breaks (and is easily fixed with glue) but we're talking about a cheap kit lens that is getting on for 40 years old...there are precious few budget plastic consumer items from that era where a good proportion of them are either still working or easily fixed. If that part were metal, maybe it would not break so much, but you surely wouldn't find it so easy to fix when it did!

[Alex645]

It's interesting how many people say that plastic mounts and barrels 'seem fragile' or 'feels flimsy' but nobody has said 'mine broke'.
I bet an impact that would break a plastic mount would bend a metal one, and both will need replacing regardless.

I was at a soccer field and someone kicked a ball full speed from behind me. The camera was on a tripod and the ball knocked the camera off the quick release plate and the impact on the grass broke the plastic lens mount. Similar things have happened to me with metal lens mounts which did not result in damage to either the lens nor the camera.

Arguably, the plastic mount might have saved the metal mount on the camera from misalignment....IDK. It would be interesting to do a series of tests blasting soccer balls at plastic and metal mount lenses and assessing the results. Those slow motion shots would go viral!!!! Anyone with a spare Canon?

[TheCousinDan]

There's no one-size-fits-all answer to this. Happy meal toys are made of plastic and so are front-line firearms and aeronautical components. All plastics are not created equal.

[wrench.doozer]

plastic snaps rather than bends.... I disagree, but I do materials testing. Get some uhmw or delrin, try to snap it. some gears are polymer for wear, sound/vibration, & sometimes planned failure. My p30t has a lot of polymer coating & is amazingly tough.
any product depends completely on manufacturing of the material. a company may change to a cheaper supplier & only do basic incoming inspection.

[reh321]

I was at a soccer field and someone kicked a ball full speed from behind me. The camera was on a tripod and the ball knocked the camera off the quick release plate and the impact on the grass broke the plastic lens mount. Similar things have happened to me with metal lens mounts which did not result in damage to either the lens nor the camera.

Arguably, the plastic mount might have saved the metal mount on the camera from misalignment....IDK. It would be interesting to do a series of tests blasting soccer balls at plastic and metal mount lenses and assessing the results. Those slow motion shots would go viral!!!! Anyone with a spare Canon?

I believe it Rupert who had a camera mount broken when the system fell. In his case, his wife purchased a K-1 for him, but not all are that fortunate. If I break a lens mount I can change lenses and keep going .... not so much with a camera mount.

[Wheatfield]

So everytime people hear abour cameras, lenses that made of plastic material
most always complain
"Oh pls
Plastic is cheap, toy-ish
Plastic is not serious
Plastic isn't durable and will fall-apart soon

overall plastic is a joke, so deal-breaker"

what do you think? is plastic really that bad?

I prefer the esthetics of metal, but at the same time I realize it is often the inferior material.

[leekil]

It's interesting how many people say that plastic mounts and barrels 'seem fragile' or 'feels flimsy' but nobody has said 'mine broke'. I wonder what the comparitive failure rates are...I bet an impact that would break a plastic mount would bend a metal one, and both will need replacing regardless.

I watched someone pick up their camera by the lens, and it somehow got stuck on their bag, and the lens mount broke off the lens. This was a Canon camera, and probably a cheap plastic as opposed to a better one, but they do break.

[sqrrl]

I have broken a plastic lens by dropping a camera (sigma 28-90 on a k10), I've also seen someone drop a metal SLR and bend the metal lens badly enough to make it non-functional. In both cases it took a fair whack.

[pathdoc]

I own two plastic-mount Pentax lenses. The first is the FA 28-90 3.5-5.6, and as a work of engineering it is abysmal (as a cheap go-to to give my K-1 flexibility for trips to the playground, it's optically more than good enough). The second is the DA50/1.8, and that inspires confidence. Plastics technology has come a long, LONG way since even the FA days.

Is the 50/1.4 S-M-C Takumar a more satisfying tactile experience (IMHO)? Heck, yeah! But metal is no longer the be-all and end-all, though it is certainly nice to have if you can afford the $$$ for a modern metal lens.

[Rondec]

I hope it's not wrong to say that I prefer some mixture of both. I wouldn't really want an old metal lens -- particularly not for very long focal lengths, but all plastic feels cheap and has poor tactile feels.