Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Plastic binos

This topic has been archived. This means that you cannot reply to this topic.
4 replies to this topic

#1 Bill Huot

Bill Huot

    Sputnik

  • -----
  • topic starter
  • Posts: 38
  • Joined: 07 Aug 2005

Posted 10 August 2005 - 12:14 AM

When I was young, the word "plastic" (like the phrase "Made in Japan") was associated with cheap and shoddy merchandise. But now, carbon fibre, polycarbonate and other modern plastics are among the best materials for many high-tech applications.

My eyeglasses have hardened polycarbonate lenses -- they're lighter and tougher than glass. So, why aren't there high quality plastic binoculars?

#2 Claudio

Claudio

    Mariner 2

  • *****
  • Posts: 277
  • Joined: 26 Jul 2004

Posted 10 August 2005 - 02:30 AM

My eyeglasses have hardened polycarbonate lenses -- they're lighter and tougher than glass. So, why aren't there high quality plastic binoculars?


Many binoculars use plastic lenses when a low cost aspherical lens is required (field lenses in the eyepieces, for example). This is generally discovered with horror when one tries to clean those lenses: it is almost impossible to avoid micro-scratches that will be very obvious when looking through the binocular. Glass is still more durable than plastic…
Claudio

#3 Bill Huot

Bill Huot

    Sputnik

  • -----
  • topic starter
  • Posts: 38
  • Joined: 07 Aug 2005

Posted 10 August 2005 - 02:53 AM

Many binoculars use plastic lenses when a low cost aspherical lens is required (field lenses in the eyepieces, for example). This is generally discovered with horror when one tries to clean those lenses: it is almost impossible to avoid micro-scratches that will be very obvious when looking through the binocular. Glass is still more durable than plastic


I appreciate that cheap plastic would not produce a quality product, but when I buy my eyeglasses with the polycarbinate lenses I get them hardened. Its pricy, but they get all kinds of abuse and I've never had a scratch. I used to get scratches when I had glass lenses.

#4 Claudio

Claudio

    Mariner 2

  • *****
  • Posts: 277
  • Joined: 26 Jul 2004

Posted 10 August 2005 - 04:50 AM

Well, my experiences with polycarbonate lenses (Zeiss) for spectacles aren't so positive.
Anyway, coming back to binoculars, we have to consider that scratches on the field lens not visible with the naked eye are magnified by the eyepiece lens and become horrendous.

In micro mechanics polycarbonate is used successfully (sometimes armoured with metal or fibres) to reduce the weight and the cost of milling and lathing metals. It has many qualities, but the problem is when it is used where metals should be preferred. I have seen polycarbonate prism clusters even in expensive binoculars (high end in their category), and they weren’t able to maintain the axes alignment. The factory made that choice to reduce the weight and probably not the costs, but it has been a bad idea.
Another typical example of wrong use of polycarbonate are the ocular bridges of many cheap and medium priced binoculars, a few threads have already commented this theme.
Steiner has been maybe the first company who adopted a special polycarbonate (makrolon) for many parts of their binoculars, even for the military ones, in order to reduce weight and to get an easy waterproofness .
Optolyth’s misuse of polycarbonate and plastics has been already discussed in the past.
Swarovski adopted polycarbonate and other interesting synthetic materials in his SL series, obtaining much more interesting results.
As far as I know the overhauling of the mentioned Steiner and Swarovski devices was limited to the replacement of the half of the binocular that had been damaged.
However, the use of special polycarbonates is increasing in the mechanics of the recent versions of quite a few premium binoculars, as their reduced weight seems to suggest.
Claudio

#5 brocknroller

brocknroller

    Surveyor 1

  • *****
  • Posts: 1,985
  • Joined: 16 Oct 2003

Posted 10 August 2005 - 02:11 PM

Polycarbonate parts for binoculars may be useful if properly applied, but I agree that using polycarbonate for the optics is a bad idea. As the article on eyeglasses in the latest issue of Sky & Telescope points out, polycarbonate has the worst color correction of any material used to make glasses. Even regular plastic corrects better. Not knowing this, I had used my thin polycarbonate glasses w/ my Celestron/EO 10X50 ED binoculars, which defeated the purpose of the ED glass. After switching to glass lenses, which decreased the FOV since they were thicker and set back farther from my eyes, the vibrant colors of the ED glass came to life, and I could see what all the fuss was about with ED glass, at least for birders. I'm not sure binocular astronomers would appreciate the increased color saturation as much. While using ED glass for 8X-10X binoculars is often pooh-pahed, even by myself, I've seen the light, oh, I've seen the (color saturated) light...

I think the reason people discount ED glass in low to medium power binoculars is that the color correction isn't as good as one would expect, because of the short FL of small binoculars. Comparing the 10X50 EDs to my Nikon 8X32 SEs, the EDs correct CA better on-axis in high contrast situations, but off axis, the SE was just as good if not a tad better.

However, the real advantage of ED glass is the subtle color differences in bird feathers, whereby a solid red Cardinal in my SEs becomes a gradiation of shades of red with the EDs, and small field markings I hadn't seen before even with a 10X42 or 12X50 SE suddenly pop out. Considering this and many birders desire to ID different species or variatons of the same species by sometimes subtle differences in color or markings, I'm surprised that more high-end birding binoculars do not feature ED glass. I haven't tried 8X ED binoculars yet, so I can't speak to enhanced colors at lower power, but at 10X, the difference is "clear".


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics