Lead And Arsenic Is A Good Thing!! (1 Viewer)

[SUPPRESSOR]

Well, it is when its in optical glass.Having owned most of the top roof prism binoculars I have come to realize that we have taken a backward step in the quality of the view since eco-glass has been introduced or to put it another way since lead and arsenic have been removed from optical glass.The backward step is increased CA,more CA in the ultravids than in the trinovid bn, more in the bn's than in the early ba's when lead and arsenic were used . I had an early pair of Leica Trinovid BA's which showed no more ca than the Zeiss fl's do now. The very reason Zeiss are using the FL glass is to reduce the excessive CA caused by utilising eco-glass.My current pride and joy is a pair of pre 2002 Nikon 8x42 HG with the lead and arsenic in the glass,apart from all of the other atributes these binoculars have, CA is so well controlled as to be virtually non existant something that can't be said about the latest model.
For those people who can't see CA don't be too smug the effects will still be there the view will not be as "pure" as it would or could have been if proper optical glass had been used.I lay some of the blame on the punters that moan about the weight of binoculars,trpods and scopes,forever wanting lighter and lighter kit well,the price to pay for this light kit can be inferior performance in a number of ways.Maybe for some , knitting might be a more suitable hobby.
..............fiddler.

 

[John Russell]

Yes, it does seem strange that optical manufacturers advertise lead and arsenic-free glass and manufacturers of quality drinking glasses emphasise the high lead content.
I don't know about the ecological issues in manufacture, but cannot imagine that the disposal or recycling of glass containing lead or arsenic poses a problem.

John

 

[jad29]

interesting, I have the 8x42LX which is superb, bought the new LXL, while really nice, the view was a 1/4 step behind, I attributed it to sample variation thinking I have a really great LX... maybe it was the glass.

 

[AlanFrench]

Anyone have any indices for the modern eco-glasses to contrast with the glasses they replaced? Or simply the glasses involved - this glass replaced this glass?

Thanks.

Clear skies, Alan

 

[FrankD]

interesting, I have the 8x42LX which is superb, bought the new LXL, while really nice, the view was a 1/4 step behind, I attributed it to sample variation thinking I have a really great LX... maybe it was the glass.

In truth, I had much the same experience. I, too, have a fairly early model of the LX and must say that the image does look somewhat "cleaner' than that of the LXL I tried at the store this past year. I also attributed it to sample variation but your hypothesis about the lead and arsenic and CA makes perfect sense.

It would also tend to explain the comments about the LXL and color fringing in the Cornell study.

Is it cheaper to make glass without lead/arsenic or is this just an environmental issue?

 

[Lewie]

But isn't there less lead and arsenic waste when eco-glass is used, and isn't this better for the environment? I am not sure that the lack affect the quality of the view, but even if it does I am willing to accept that if it is better for the environment.

If we are going to argue for the use of lead, we should also be arguing for the use of lead in paints. There is no way that non-lead paints last as long or protect as well as the old lead-based paints. (I am not pushing for bringing back lead-based paints; just making a point.)

Lew

 

[clschmalz]

But isn't there less lead and arsenic waste when eco-glass is used, and isn't this better for the environment? I am not sure that the lack affect the quality of the view, but even if it does I am willing to accept that if it is better for the environment.

If we are going to argue for the use of lead, we should also be arguing for the use of lead in paints. There is no way that non-lead paints last as long or protect as well as the old lead-based paints. (I am not pushing for bringing back lead-based paints; just making a point.)

Lew

In the course of a 40+ year chemical career I was involved in a number of reagent replcements in the name of ecology. Almost without exception the replacement's performance was poorer. Obviously the original compounds had been chosen because they gave the best results.

One has to be careful and weigh the cost/benefits when making such decisions. In the case of optical glass I think the issue may be overstated and clouded with emotion. The ecological cost of producing the glass can be controlled with modern emmission and waste management technology. The finished product is essentialy inert with the toxic elements firmly bound in the glass matrix. Additionally the original formulation performs better than the substitute. I suspect the drivers for change in this case are more public relations than engineering based.

Remember Grandma used lard in her pie crust because it worked beter than Crisco.

Charlie

 

[Tero]

The binocular makers only make the lenses, not the glass. They are dependent on what is available to them in glass raw material. The coatings are another matter, those they work with.

 

[SUPPRESSOR]

The lead and arsenic was put in the glass to make it denser serving the same purpose as ED glass ie help in keeping CA to a minimum.Removing the lead and arsenic makes the glass lighter this goes towards making the binocular lighter.More and more people are taking up birding, alot of them are getting on in years they will not buy a binocular if it is too heavy for them, binoculer makers need to sell lots of binoculars hence lighter glass,lighter bodies, lighter rubber armour etc,they are even thinking about plastic lenses all of this can have its price and not just in cash terms.If like me you appreciate those deep rich colours and the very best clean,crisp view, hang on to those early Leica Trinovid BAs and the pre 2002 Nikon HG/LX,neither model a gramme to heavy for the image they give and worth alot more money than you can get for selling them on the second hand market.
.............................................fiddler.

 

[Atomic Chicken]

Fiddler,

The lead and arsenic was put in the glass to make it denser serving the same purpose as ED glass ie help in keeping CA to a minimum.Removing the lead and arsenic makes the glass lighter this goes towards making the binocular lighter.More and more people are taking up birding, alot of them are getting on in years they will not buy a binocular if it is too heavy for them, binoculer makers need to sell lots of binoculars hence lighter glass,lighter bodies, lighter rubber armour etc,they are even thinking about plastic lenses all of this can have its price and not just in cash terms.If like me you appreciate those deep rich colours and the very best clean,crisp view, hang on to those early Leica Trinovid BAs and the pre 2002 Nikon HG/LX,neither model a gramme to heavy for the image they give and worth alot more money than you can get for selling them on the second hand market.
.............................................fiddler.

I agree with your post - with the exception of the glass weight issue. I do not believe that adding Lead or Arsenic will increase the weight of the glass to any perceptible degree - the extra gram or two of weight for leaded glass is insignificant when compared to other binocular components like the frame and focus mechanism components.

I personally agree with user "clschmalz" in his earlier posting - that the decision to use "eco-friendly" glass is an emotionally based marketing decision, and not rooted in any kind of real health/environmental problem like leaded paint or Asbestos were.

Best wishes,
Bawko

 

[jad29]

I don't know if my LX are 2002 or earlier, just know they looked better then the LXL. out of curiosity any idea what serial # range were talking?

 

[Lewie]

Some interesting posts here. Posts about marketing make sense. I am also wondering if it was a purely cost decision, in that lead-free and arsenic-free optics are cheaper. Anyone know?

 

[AlanFrench]

No old glass, with or without lead and arsenic, had optical properties similar to fluorite or fluor-crown glasses. In order to make an objective that is well corrected for aberrations, of reasonably focal length, and with curves and tolerances that lend themselves to a production environment, you need to pick glasses with markedly different dispersions. Until the advent of ED (Extra-low Dispersion) materials such a choice meant a secondary spectrum of about 1 part in 2000.

Clear skies, Alan

 

[SUPPRESSOR]

Fiddler,




I agree with your post - with the exception of the glass weight issue. I do not believe that adding Lead or Arsenic will increase the weight of the glass to any perceptible degree - the extra gram or two of weight for leaded glass is insignificant when compared to other binocular components like the frame and focus mechanism components.

I personally agree with user "clschmalz" in his earlier posting - that the decision to use "eco-friendly" glass is an emotionally based marketing decision, and not rooted in any kind of real health/environmental problem like leaded paint or Asbestos were.

Best wishes,
Bawko[/QUOTE As far as I understand it the eco-glass lenses are also thinner so saving a bit of weight that way.Whatever the reasons for using it,I know which I prefer to look through.
.............................fiddler.

 

[elkcub]

Fiddler,




I agree with your post - with the exception of the glass weight issue. I do not believe that adding Lead or Arsenic will increase the weight of the glass to any perceptible degree - the extra gram or two of weight for leaded glass is insignificant when compared to other binocular components like the frame and focus mechanism components.

I personally agree with user "clschmalz" in his earlier posting - that the decision to use "eco-friendly" glass is an emotionally based marketing decision, and not rooted in any kind of real health/environmental problem like leaded paint or Asbestos were.

Best wishes,
Bawko[/QUOTE As far as I understand it the eco-glass lenses are also thinner so saving a bit of weight that way.Whatever the reasons for using it,I know which I prefer to look through.
.............................fiddler.

I respectfully disagree regarding the motivation for, and ecological advantages of, eco-friendly glass. I've attached a brief .pdf file by Nikon regarding their program, much of which simply doesn't square with earlier statements, either about the insubstantial bio-risk reduction or compromized performance of the new glass. Basically, the problem is in the glass manufacturing and optical fabrication processes, rather than the toxic residuals retained by the glass itself (which was stated before). I really don't believe for a minute that it's a sales gimmick or public over-reaction, but rather a poster child for socially responsible corporate behavior. Of course, I did live near the "Love Canal" in Buffalo, NY during the early 1960's, and have a very sober idea of how corporations can be completely irresponsibe. So, I for one think we owe a debt of gratitude to Nikon (and others).

ED

 

[Blackstart]

I respectfully disagree regarding the motivation for, and ecological advantages of, eco-friendly glass. I've attached a brief .pdf file by Nikon regarding their program, much of which simply doesn't square with earlier statements, either about the substantial bio-risk reduction or compromized performance of the new glass. Basically, the problem is in the glass manufacturing and optical fabrication processes, rather than the toxic residuals retained by the glass itself (which was stated before). I really don't believe for a minute that it's a sales gimmick or public over-reaction, but rather a poster child for socially responsible corporate behavior. Of course, I did live near the "Love Canal" in Buffalo, NY during the early 1960's, and have a very sober idea of how corporations can be completely irresponsibe. So, I for one think we owe a debt of gratitude to Nikon (and others).

ED

Thanks for the file attachment, Ed. Whatever the motivation, the toxic substances in question have been removed from the manufacturing process, and that's a good thing no matter how you look at it.

Fiddler, I must say I've never once thought about any shortcomings of the eco-glass in my Nikon EII, nor about CA or corporate marketing decisions. Life's too short, and looking at birds is much more interesting.

Adam

 

[iporali]

The lead and arsenic was put in the glass to make it denser serving the same purpose as ED glass ie help in keeping CA to a minimum.

This is very interesting discussion, but I have a hard time believing that lead and arsenic would actually reduce CA or dispersion. I really can't call myself an expert, but I have seen some sloppy optics terminology (esp. in marketing materials of many manufacturers), which may have lead to confusion. Alan or anyone else may feel free to correct my facts if necessary, but anyway - I'll try to make a couple of points about glass properties and composition, which have been quite confusing to me.

Eg. Swarovski calls their ED glass a "HD", which I have often seen translated into "high density" (http://www.birds.cornell.edu/AllAboutBirds/gear/scopes/sc_review, www.njaudubon.org/NatureNotes/PickScopes05.pdf, http://www.optics4birding.com/ChScop.aspx) - which it is not (optically or physically). It should be "High Definition" which does not mean anything specific. For some reason this "density" is often associated with ED glasses.

You can increase refractive index of the glass (sometimes called "optical density") by adding up to 60% lead oxides (+ arsenium ?). This increases both optical and physical "density" (makes glass heavy) of the glass, but also its dispersion ("CA tendency"). Weight (density), refractive index (optical density) and dispersion (Abbe number) are thus independent factors which only have some correlation: Fluorite (=lightweight, low RI, extra low dispersion) in one end and "Dense Flint" SF (=heavy, lead containing, high RI, high CA/dispersion) in the other end of the RI/Abbe number scale. See http://en.wikipedia.org/wiki/Abbe_number.

When you have an achromatic doublet in a binocular objective, you may have a low dispersion crown lens (+) together with a high dispersion (lead-containing?) flint lens (-). Here you actually take advantage of "poor" dispersion properties of high-RI flint glass, by reversing the dispersion of the first lens with a second lens. The idea is that the second lens corrects CA more than it affects to the focal length.

IMO you can't get ED/HD-like glass by putting lead or arsene in it. You may get a high-dispersion (!) glass, which can be used as a "correcting" lens, but there is such a wide selection of optical glasses available that if you end up increasing CA with eco-glass (lead replaced with titanium etc.), it is a matter of poor design or manufacturing or something else. One hypothesis could be that greenish version of CA may be more difficult to see in older optics, which often have a yellow color cast due to older lens/mirror coating technologies.

Best regards,

Ilkka

 

[AlanFrench]

Ilkka,

It is little wonder that people are confused about "density" when it comes to optical glass. Pete Dunne has written, in at least two places, the ED stands for Extra Dense. Here on this forum Stephen Ingraham writes "The same density that gives it its low dispersion also makes it quite a bit heavier than other glass." If the perceived experts get it wrong, then it is little wonder that others make the same mistake.

I'd like to expand a little on what you wrote about optical density, which is what is really meant when opticians label glass as "dense." Optical density is a measure of how much the glass slows light down. Light takes longer to travel through a glass with high optical density. Since the refractive index is the ratio of the speed of light in a vacuum to the speed of light in the glass, it is, as you write, a measure of optical density.

Glasses with an index of refraction of 1.58 are called light flints. Glasses with an index of 1.66 are known as dense flints. One of the best ED materials, FPL 53, has an index of 1.44, so even calling it optically dense would be a mistake.

Clear skies, Alan

 

[Pileatus]

http://ec.europa.eu/comm/environment/waste/stakeholders/individual_bus/cooke/submission.pdf

 

[AlanFrench]

http://ec.europa.eu/comm/environment/waste/stakeholders/individual_bus/cooke/submission.pdf

John,

An interesting read. I will be seeing some folks this weekend who make a living designing and making optics, and I will ask if they find the move toward lead and cadmium free glasses has hampered their efforts.

Clear skies, Alan