"WEBVTTKind: captionsLanguage: enjoin us now on Flickr at flickr.com slrps slart of Photography welcome to the Art of Photography I'm Ted Forbes today we're going to do part two in our lens discussion here and today what I want to do is talk about what lenses are made up if you were to open a lens what are you going to find inside okay now lenses are made up of a series of op called elements and elements look like oh little lenses themselves and uh basically uh there are two types of classifications um when you're talking about lens elements the first classification is what you what's known as a simple lens and a simple lens contains only one element and these are usually found on cheaper lowbudget cameras plastic cameras old box cameras the hogga is a single element lens it's a simple lens and then you have the compound lenses which contain more than one element okay now how many elements can these contain well it depends from lens to lens some of the more expensive zoom lenses uh contain up to 20 elements or sometimes more now why would you use more than one element in a lens well lenses by nature in theory you can project and refract light onto your focal plane using only one element and that in theory is why hogas work which is why box cameras work all those kinds of things but uh you know in reality they're kind of guilty of every lens Distortion you're possibly going to be able to find in photography which is kind of cool and at the same time kind of weird too because if you're looking for a perfect photo that you're going to put on a magazine cover something like that maybe it's not what you're going for but if you're going for kind of an Arty style and you really want to embrace a lot of those imperfections and distortions uh the that's why the hogo is right up a lot of people's alley because it it tends to Showcase all of those now um lenses are not lens elements are not ever Perfect by Design because you get these distortions so there are different kinds of lens elements and when you group and combine these elements you can such bend the light so you get get rid of a lot of those imperfections and you create you correct a lot of those distortions so what I want to do is take a minute here and let's talk about the various types of lens elements okay so we're going to look at a website here um to use for our illustration of U of ly's elements here and I am on the Canon camera Museum website which is a page on Canon's website and the URL to get there is canon.com camera- Museum and this is a great resource for all things Canon and they have obviously a lot of specifications and stuff on both Uh current currently in production products and stuff that they don't make anymore which is kind of a nice resource but if I go over here to camera Hall and uh we go down and select lenses we'll go by series name here I'm going to select EF Mount this is what's currently in production and let's select uh standard medium telephoto and I'll pick just the standard 1.4 50 mm lens and we get a page for this with some specifications on it and you see down here in this list of specs that there are two that we're going to talk about today there's lens construction and groups and lens construction by element and we can see that there are six groups to this lens and seven elements now what does this mean well let's go to the block diagram here and we get a cross-section of the lens since I don't actually have a lens that I'm willing to rip open for this demonstration but you can see that if you took the lens apart uh there are indeed seven lens elements and they all line up on this on the lens axis which runs down the middle now when we get into aspherical lenses uh there are ways to craft lenses where the axis is not directly down the middle that can be really handy for correcting distortions too but for our purposes here you can see that indeed there are seven elements running across uh running through the lens here and they're made out of glass usually I'm sure they are in this case and you can see that towards the back here you have these two elements that're stuck together and they're probably cemented together there's no air in between them and this is uh known as a lens grouping okay uh where you take more than one element and you combine them to make a group now it's also a group can be a lens on its own so you can see here that we have seven elements but they're in six groups groups because these two are connected together and they're connected together to u to manipulate the refraction and take care of some of the distortions you might find in a lens so let's look at Lens elements specifically and I have an EPS document that I put together here and you can see that these are these six basic types of lens elements that can be combined now what happens is if you look at a lens element light will come through the front side of the element and the lens element manipulates that light and refracts it and bends it and it comes out the backside in a different configuration and we're going to get more into this in a second but let's look at what the basic types are um you have basically they're they're kind of named by the type of side they have so if you you know you're looking at this from its side uh if this if you have a uh concave surface or excuse me a convex surface it bends out concave surfaces Bend IN like this last element here if you remember from high school geometry it bends in like a cave so that would be concave so the first element on the far left here this is what's known as a bioc convex element because there are two convex sides so bio convex this next one here is a Plano convex it has one convex side and one plane so it's Plano convex let's skip over these middle two for just a second we're going to come back these are the meniscus lenses uh then you have a Plano concave obviously and then a bio concave two concave sides now the two in the middle these are both meniscus lenses okay and so these are a lot like what you're going to see in eyeglasses and they're going to be what you see in single or simple lenses like that on a hulo or a box camera something like that that just contains one element and basically what they're going to do is the light comes through the front side and they have two concave sides um and the light will project back and all come to a center point that is the focal plane that's where your digital sensor is or your film sensor in the hogga or something like that excuse me film sensor is where your film is uh so anyway so that's your focal distance now when you focus the lens you move this back and forth and you can focus on different points of light that would be in your scene on the front side and so you can manipulate what that focal point is and you'll see on here that the uh front side on this one has a steeper curve than the back side so this is what's known as a positive meniscus lens the second lens is a negative meniscus lens the back side is a much steeper curve than the front side in this case so that's basically the six lens types um there's also a spherical lenses which we'll get into later because they are a little more advanced came along later but this is the uh six elements that we're going to be dealing with for our purposes here a lot of times it's real common when you see people that get really caught up in equipment especially when they're pouring a lot of money into their equipment uh that they're always looking for this perfect lens or this perfect thing and I will say this that there's a lot to be said for dealing with plastic cameras simple lenses uh you get kind of a soulle to your image that you don't get when everything is perfectly corrected and uh I just want to make sure that I I've made that point that that spending a lot of money on equipment doesn't always mean you're going to get their best results and certainly I don't think in any instance is it going to make you a better photographer I've seen very wonderful photos with with if you really look closely you're going to see problems with the lenses and distortions and things like that that may not be perfect but I will make the point too that that I've never ever seen an incredible shot and held that kind of thing against it I've also seen the opposite where you have these these beautiful shots because technically they're perfect the lens looks wonderful the camera looks wonderful the picture's sharp it's clean it's it's uh the colors are well saturated it's vibrant and it's just not a great picture and uh you don't tend to look back a second time at those so anyway with all this stuff taken with a grain of salt but uh anyway I hope that helps and we're going to talk some more about lenses in the next couple podcasts so this has been the Art of Photography and thanks for watchingjoin us now on Flickr at flickr.com slrps slart of Photography welcome to the Art of Photography I'm Ted Forbes today we're going to do part two in our lens discussion here and today what I want to do is talk about what lenses are made up if you were to open a lens what are you going to find inside okay now lenses are made up of a series of op called elements and elements look like oh little lenses themselves and uh basically uh there are two types of classifications um when you're talking about lens elements the first classification is what you what's known as a simple lens and a simple lens contains only one element and these are usually found on cheaper lowbudget cameras plastic cameras old box cameras the hogga is a single element lens it's a simple lens and then you have the compound lenses which contain more than one element okay now how many elements can these contain well it depends from lens to lens some of the more expensive zoom lenses uh contain up to 20 elements or sometimes more now why would you use more than one element in a lens well lenses by nature in theory you can project and refract light onto your focal plane using only one element and that in theory is why hogas work which is why box cameras work all those kinds of things but uh you know in reality they're kind of guilty of every lens Distortion you're possibly going to be able to find in photography which is kind of cool and at the same time kind of weird too because if you're looking for a perfect photo that you're going to put on a magazine cover something like that maybe it's not what you're going for but if you're going for kind of an Arty style and you really want to embrace a lot of those imperfections and distortions uh the that's why the hogo is right up a lot of people's alley because it it tends to Showcase all of those now um lenses are not lens elements are not ever Perfect by Design because you get these distortions so there are different kinds of lens elements and when you group and combine these elements you can such bend the light so you get get rid of a lot of those imperfections and you create you correct a lot of those distortions so what I want to do is take a minute here and let's talk about the various types of lens elements okay so we're going to look at a website here um to use for our illustration of U of ly's elements here and I am on the Canon camera Museum website which is a page on Canon's website and the URL to get there is canon.com camera- Museum and this is a great resource for all things Canon and they have obviously a lot of specifications and stuff on both Uh current currently in production products and stuff that they don't make anymore which is kind of a nice resource but if I go over here to camera Hall and uh we go down and select lenses we'll go by series name here I'm going to select EF Mount this is what's currently in production and let's select uh standard medium telephoto and I'll pick just the standard 1.4 50 mm lens and we get a page for this with some specifications on it and you see down here in this list of specs that there are two that we're going to talk about today there's lens construction and groups and lens construction by element and we can see that there are six groups to this lens and seven elements now what does this mean well let's go to the block diagram here and we get a cross-section of the lens since I don't actually have a lens that I'm willing to rip open for this demonstration but you can see that if you took the lens apart uh there are indeed seven lens elements and they all line up on this on the lens axis which runs down the middle now when we get into aspherical lenses uh there are ways to craft lenses where the axis is not directly down the middle that can be really handy for correcting distortions too but for our purposes here you can see that indeed there are seven elements running across uh running through the lens here and they're made out of glass usually I'm sure they are in this case and you can see that towards the back here you have these two elements that're stuck together and they're probably cemented together there's no air in between them and this is uh known as a lens grouping okay uh where you take more than one element and you combine them to make a group now it's also a group can be a lens on its own so you can see here that we have seven elements but they're in six groups groups because these two are connected together and they're connected together to u to manipulate the refraction and take care of some of the distortions you might find in a lens so let's look at Lens elements specifically and I have an EPS document that I put together here and you can see that these are these six basic types of lens elements that can be combined now what happens is if you look at a lens element light will come through the front side of the element and the lens element manipulates that light and refracts it and bends it and it comes out the backside in a different configuration and we're going to get more into this in a second but let's look at what the basic types are um you have basically they're they're kind of named by the type of side they have so if you you know you're looking at this from its side uh if this if you have a uh concave surface or excuse me a convex surface it bends out concave surfaces Bend IN like this last element here if you remember from high school geometry it bends in like a cave so that would be concave so the first element on the far left here this is what's known as a bioc convex element because there are two convex sides so bio convex this next one here is a Plano convex it has one convex side and one plane so it's Plano convex let's skip over these middle two for just a second we're going to come back these are the meniscus lenses uh then you have a Plano concave obviously and then a bio concave two concave sides now the two in the middle these are both meniscus lenses okay and so these are a lot like what you're going to see in eyeglasses and they're going to be what you see in single or simple lenses like that on a hulo or a box camera something like that that just contains one element and basically what they're going to do is the light comes through the front side and they have two concave sides um and the light will project back and all come to a center point that is the focal plane that's where your digital sensor is or your film sensor in the hogga or something like that excuse me film sensor is where your film is uh so anyway so that's your focal distance now when you focus the lens you move this back and forth and you can focus on different points of light that would be in your scene on the front side and so you can manipulate what that focal point is and you'll see on here that the uh front side on this one has a steeper curve than the back side so this is what's known as a positive meniscus lens the second lens is a negative meniscus lens the back side is a much steeper curve than the front side in this case so that's basically the six lens types um there's also a spherical lenses which we'll get into later because they are a little more advanced came along later but this is the uh six elements that we're going to be dealing with for our purposes here a lot of times it's real common when you see people that get really caught up in equipment especially when they're pouring a lot of money into their equipment uh that they're always looking for this perfect lens or this perfect thing and I will say this that there's a lot to be said for dealing with plastic cameras simple lenses uh you get kind of a soulle to your image that you don't get when everything is perfectly corrected and uh I just want to make sure that I I've made that point that that spending a lot of money on equipment doesn't always mean you're going to get their best results and certainly I don't think in any instance is it going to make you a better photographer I've seen very wonderful photos with with if you really look closely you're going to see problems with the lenses and distortions and things like that that may not be perfect but I will make the point too that that I've never ever seen an incredible shot and held that kind of thing against it I've also seen the opposite where you have these these beautiful shots because technically they're perfect the lens looks wonderful the camera looks wonderful the picture's sharp it's clean it's it's uh the colors are well saturated it's vibrant and it's just not a great picture and uh you don't tend to look back a second time at those so anyway with all this stuff taken with a grain of salt but uh anyway I hope that helps and we're going to talk some more about lenses in the next couple podcasts so this has been the Art of Photography and thanks for watching\n"