Canon Lens Composition
so beyond kind of the standard glass can and developed ultra low dispersion glass. And so dispersion is when light hits a lens and it disperses it goes off somewhere else. And we don't like that because we're losing that light source. Okay, so they designed ud glass to correct for this chromatic aberration of light hitting glass and kind of taking off doing its own thing. And so there's a full list of lenses. And for those of you who by the class and get the pdf, you don't have to write all these numbers down. You go back and you can just look at this slide number and you can pull up the whole list of these air lenses that have ud glass and one of the things I really want to make sure getting this list right current and up to date of which ones have all this in here. So this is a significant improvement over normal glass because image quality, less chromatic aberration, less dispersion of the glass as we shooting images, improved contrast, improved sharpness because of this type of gla...
ss that is in there and there's a type of class we're going to talk about next called fluoride, and this is a much cheaper glass to use in that. So it's a relatively affordable way of improving the quality of the glass of our lenses. Now, this is originally called you D, and they have since made subsequent improvements to it and they now call it Super You d class. And so, if you see super you d that's this higher in type glass. But then along came fluoride. Alright, So fluoride is a rare earth element and it isn't in a fairly elite collection of lenses that you'll see listed here on the left of your screen. And fluoride is a rather interesting element is that you're going to get pretty much know chromatic aberration at all if you use it Excellent. Let's put in all of our lenses. One fluoride element has the power of to you d elements. Awesome. We just saved money and wait by reducing the number of elements in our lands, we're gonna make our land smaller now because we're using these fluoride elements. This is great news. Love to hear about this new technology. Very low refractive index, so refract Okay, what is refract reflect and we all know what reflect ISS. We see our reflection in a mere light bounces off of a surface. Okay, When you react to something, what happens, move along. Something happens. Okay, React to that. All right, So when light hits glass dispersion refraction, it takes often into a different direction. Very low refractive index, which means the light is going where it's supposed to go very low dispersion. This is all sounding really good. Here's a problem. Natural fluoride is too small for photographic lenses. So when you find natural floor, I I don't know what exactly looks like, but it's too small to just grind it and put it in a lance. It will work out for certain types of small microscopes, but it's not big enough toe work put in a regular lens. So Canon grows their own synthetic fluoride crystals that they put in their lenses. So in case you're wondering, why does this 200 to 400 lens cost $10,000 because they're growing Gloria class crystals to put in your lands? How long does that take? I don't know, but it can take quite some time. I know there are certain lenses that take more than 18 months from the beginning of the lens curing process. And so sometimes they're working on these lens elements, and they're in bats and heating up and cooling down, going through cycles for weeks at a time. And it takes four times longer to grind a fluoride element than it does a U. D or a standard glass element. They're very fragile, and they could be broken. And so they have to be able to be mounted in very strong lenses so that they don't get moved in the wrong way. And so imagine if you're breaking four times the amount of glass every time you're trying to grind it. That's gonna increase the cost of that lens quite a bit. And so the lenses, as I say, this is a pretty lofty line of lenses that are using these fluoride elements, but you will see it listed as one of the elements that is part of that lens design