EF 400 f/4 L IS USM

[Jon Ruyle]

How does plastic do with chromatic abberation? I would guess terrible, but I don't know.

[Bob]

<p class="MsoNormal" style="margin: 0in 0in 10pt;"]<span style="line-height: 115%; font-family: 'Arial','sans-serif'; font-size: 12pt;"]<o></o>
<p class="MsoNormal" style="margin: 0in 0in 10pt;"]<span style="line-height: 115%; font-family: 'Arial','sans-serif'; color: black; font-size: 12pt;"]Alan,


<span style="line-height: 115%; font-family: 'Arial','sans-serif'; color: black; font-size: 12pt;"]
<p class="MsoNormal" style="margin: 0in 0in 10pt;"]<span style="font-family: 'Arial','sans-serif'; color: black;"]Don&rsquo;t want to burst your bubble, but optical "plastics" are already used by the military.<span style="mso-spacerun: yes;"] The remarks you stated can be true for old types of non optical &ldquo;plastics&rdquo;. The chemistry of "plastics" has had many developments over the past 5 years. By the way, a &ldquo;Hybrid Lens&rdquo; uses both plastics and glass.<span style="mso-spacerun: yes;"] What is glass &ndash; many different things?<span style="line-height: 115%; font-family: 'Arial','sans-serif'; font-size: 12pt;"]<o></o>

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[Alan]

<p class="MsoNormal" style="margin: 0in 0in 10pt;"]<span style="line-height: 115%; font-size: 12pt; font-family: 'Arial','sans-serif';"]
<p class="MsoNormal" style="margin: 0in 0in 10pt;"]<span style="line-height: 115%; font-size: 12pt; font-family: 'Arial','sans-serif'; color: black;"]Alan,


<span style="line-height: 115%; font-size: 12pt; font-family: 'Arial','sans-serif'; color: black;"]
<p class="MsoNormal" style="margin: 0in 0in 10pt;"]<span style="font-family: 'Arial','sans-serif'; color: black;"]Don&rsquo;t want to burst your bubble, but optical "plastics" are already used by the military.<span> The remarks you stated can be true for old types of non optical &ldquo;plastics&rdquo;. The chemistry of "plastics" has had many developments over the past 5 years. By the way, a &ldquo;Hybrid Lens&rdquo; uses both plastics and glass.<span> What is glass &ndash; many different things?<span style="line-height: 115%; font-size: 12pt; font-family: 'Arial','sans-serif';"]

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I'm not doubting that they use optical plastics in the military. For precision optics, I question the use in lenses, in the field, where the average joe is using them.


Glass is a generic term, but the average person understands this term to be glass, as in window glass. It's amorphous, but it is essentially (though, not exclusively) one thing: silicon dioxide. Plastics, on the other hand, are synthesized from small molecules, and have other components in them, such as plasticizers, flexibilizers, stabilizers. All of these contribute to give the plastic its characteristic (flexibility, processing temp., etc.)


Glass in lenses is just not as complicated. It's purity of the glass, and it's formation to give optically clear devices that matters highly.


Another thing to consider is refractive index of the two materials.


They might well make a hybrid, but what part is the glass, and what part is the plastic?


I'm not holding my breath on the changeover. Until then, I'm sticking with glass.