Why is Window Glass So Bad to Shoot Through?

Started 3 months ago | Questions thread
Doug Haag Senior Member • Posts: 2,345
Re: Why is Window Glass So Bad to Shoot Through?

FrancoD wrote:

Doug Haag wrote:

Clickalot wrote:

I guess it's a lesson in why optical glass costs buckets of dough, but I've learned that even freshly cleaned, streak-free window glass destroys fine detail and creates haze in pix taken through it no matter how scrupulously one chooses outdoor light conditions that obviate room/clothing reflections.

It's probably got to to with molecules and crystalline structure and stuff, no?

Glass is a strange material in that even when cooled from its molten state to a solid it does not have a crystalline structure. Although not a perfect analogy, think of it as a liquid that, at room temperature, has become so viscous that it seems rigid. The reason this is not a perfect analogy is that it would appear to explain why some centuries old windows are thicker at the bottom than at the top -- the "liquid" having slumped over time. But that is not the explanation for that phenomenon which can be Googled.

Anyway https://www.google.com/search?client=firefox-b-d&sxsrf=ALeKk02EBerKbgFkDVPtThZWpgAagp98wQ%3A1603195959471&source=hp&ei=N9SOX42uGtGktQb88btA&q=does+glass+have+a+crystalline+structure&oq=does+glass+have&gs_lcp=CgZwc3ktYWIQARgAMgUIABDJAzICCAAyAggAMgIIADICCAAyAggAMgIIADICCAAyAggAMgIIADoECCMQJzoICC4QsQMQgwE6CAgAELEDEIMBOgsILhCxAxDHARCjAjoFCAAQsQM6CAgAELEDEMkDUOsOWJE_YNZWaABwAHgAgAFsiAHzCZIBBDE0LjGYAQCgAQGqAQdnd3Mtd2l6&sclient=psy-ab

No that is not true. Those glass panes were made like that.

Glass used to be span out by hand, so the outside became slightly thicker than the inside part. It seemed logical to put the thicker part always at the bottom.

Are you unable to read English and comprehend what you read?  I said that because glass at room temperature is like a very viscous fluid, that characteristic would "appear" to explain why ancient glass is thicker at the bottom."  I immediately followed that up by saying that is NOT the explanation for the phenomenon and that the real reason can be Googled.

You apparently did the Googling and discovered that I was correct about there being a different reason.  But then you bolded a portion of my text, ignored the rest of what I wrote, and proclaimed an error.  Brilliant.

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