how about in extreme temperatures like a hot sunny day in Middle East or cold winter in Russia ? will glass perform better ?
Last edited by Artosoft; 12th December 2006 at 12:18 PM. Reason: Not go to the moon, outer space.
When I do some holiday works in my uncle optical more than 15yrs ago, I was told that glass allows more lights to pass thru compare with plastic.
If I remember correctly, it's like 98% or 99% for glass lens,
but for plastic lens it's like less than 95%.
Dunno whether the above still true today but generally it coincide with my feeling when I look thru glass spectacle and plastic ones.. the glass always seems clearer and sharper..
Ok, here's some differences I can think of. I'm not a plastic or glass expert so I don't know whether the newest technology can overcome some/all of these differences:
hardness (resistance to scratching) - glass is ahead
aging (discolouration/brittleness) - glass is ahead
resistance to chemicals - glass is ahead
operating temperature range - glass is ahead
size/weight - ? plastic is lighter
distortion - ?
manufacturing process - those famous lens makers all have decades of experience with glass and have honed their processes thru the ages. If they move to plastic, they will need new tooling, new skills, new processes.
Feel free to discuss.
The fluorite elements might be more fragile as compared to glass... however if the problem is that serious, there would have more than it's fair share of "complaints" in online forums. Especially for those whom like to gaffer/camo their long whites.
Some light hearted discussions I've dug out Are fluorite lenses prone to cracking?
From FM'n Nikon forum...read the last post in page 1 Note about the comment regarding focus correction.
Read the portion on L lens IMHO is the more accurate reason why are longer lenses white even they might not have fluorite element in them.
1. As explained below.
2. Already got a very old discussion on this... I tot already pointed out that it's due to the red tapes in certification process that it's simpler to use something that's pre-approved then to put something new for approval for space flights. It's not only the lens the body too.
OT a bit... while trawling the net I came across this very nice pics.
*edit* and ohh... the one that made history.
Loss of coating can effect on picture quality. That's why cleaning fungus usually will remove the coating and the lens quality is affected.
I use a very high grade acrylic (call it plastic if you like) for framing my better artwork. The product is called Acrylite OP3 and it is made in the US. The optical quality is excellent, plus it is UV filtering.
The main reason why I use the OP3 is because it is:
2. Much lighter than glass
3. UV Filtering
Similar glass sheets would weigh too much, and to give it a UV filtering coat will skyrocket the price.
Incidentally, the cockpit of fighter planes are made of high grade acrylic as well... because glass shatters.
Don't know how does that do for your analysis, but thought you'd like to know.