Time to dive into the second big aspect of lenses as to why you would choose a particular lands or how you were going to use the lands that is, of course, the aperture of the lands it seems fairly intuitive it's something we talk about in basic photography we're going to cover a few of the basics in here, but there's a more advanced topics that we also want to talk about as well in here, and so I got a lot of different things that were going to be covering in this little section here, starting with the aperture range, so this is this is a little kind of review of photo one o one, you might say we have lenses that have aperture units, little openings that we can adjust in there, and we're going to use this aperture in order to control the amount of light coming in the camera. But this also controls our depth of field, so if we have a lens that goes down to one point for it's going to have the ability to shoot very shallow depth of field on your screen on the right side, you'll see those...
red hash marks are slowly growing in size. You might say, as we are stopping our appetizer down, we're getting mohr depth of field and between each one of these settings and the next it's really not that big difference, but when we start adding up the difference between one point four in f twenty two there's going to be a huge difference in what your lens sees and what it has in focus and so being familiar with this is, uh you know, part of that photo one one education that you should have and so in your lens there are all these different f stops that we're going to be setting and there's kind of different increments that we typically work in in the world of photography two point eight if we go from two point eight two two point oh, we are opening our lens up by one full stop, which means we are doubling the amount of light this is the increments that we usually kind of talk about when we are in photography is doubling the amount of light as a full stop up or we could close it down or stop it down and we're letting in a full stop less light in this case going from two eight two four is half the amount of light, so we have a lot of different lenses out there. For instance nikon makes a fifty millimeter one point four and they make a one point eight millimetre land so I questioned for our in studio audience is if each of these lenses air said it two point eight will they have the same exposure and the same depth of field and so the question really is a swell this one point four lands let's in more light but if they're said it two point eight are they the same or different so let's just get you to raise your hands if you think they will have the same exposure and the same depth of field who thinks that they will be different okay the correct answer is yes they will have the same exposure and the same depth of field and that is because they're both set at two point eight the fact that this is a one point four makes no difference once you've said it to two point eight and so it lets in more light but on lee when it's at one point four and this is one of the areas that I got mixed up because I thought when you bought a one point four lands it always let in more light no on lee when it was at that maximum setting now it may have better glass quality they have better focusing it may have other features that air nice that carry forward but when it comes to exposure and depth of field, the only thing that matters is what's the number that is set so when we are looking at purchasing lenses when we're trying to get that shallow depth of field, what we're really looking at is the maximum aperture on our lands mountain how much light doesn't let ian, at its maximum opening, really lets us know how it works under low light conditions. Some of the different types of lenses that you might see is a fixed or a prime lens is going to have one number because it doesn't have a zoom it's just gonna always have one number and one colon that's kind of the priest preamble to the actual number that we're getting to, which is a one it's a one point four lands in f one point for lands the zoom lenses typically have two numbers because we have a zoom setting on the white end and on the telephoto and or it one extreme to the other extreme, and the numbers very a little bit. These lenses are a little bit easier to make than the third option, which is a zoom lands that has just a single number. So in this case, it's an f four lens, no matter what focal length you choose so it's a twenty four to one twenty you can shoot it at twenty at f or you can shoot it at one twenty four. Where is this other lands? It's going to be a three point five maximum opening at sixteen and it's going to be a five point six opening at eighty five because it zooms back and forth various and so we're going to talk more about this. What? This is all confusing? Just hang with us will continue to talk about this now the fifty millimeter one point four lands is written as fifty. Mm one colon one point for every once in a while I have someone I'd ask someone what lens they have and they would say, I have a one point one point four, lads, no, no it's, a colon, and that part kind of doesn't matter. And so what the one colon means is it means the focal length over whatever number comes after. So in this case, the one represents fifty because it's fifty millimeter land. So we put the focal length over that number, and this allows us to write it in one line when we don't have a big chalkboard, write things on different lines, and so they can write it on one line of the lens right here, and so fifty millimeters, divided by one point four is thirty five millimeters, and what is thirty five millimeters about this lens is the opening across. Through which light travels it's not the outside diameter of the lands but if you were to hold the lens upto light and make sure the aperture was all the way open it's how much light would be getting through that lands? And so we can figure out how big of opening is in any lands with the focal length and the aperture so we know this is a thirty five millimeter opening what about that other lens? I was just talking about a moment ago. The fifty millimeter, one point eight lance fifty millimeters divided by one point eight is twenty eight millimeters so it's a little bit smaller opening this lens lets in more light than the fifty one eight. So nikon actually still makes a fifty millimeter one point two it's a manual focus lands but a one point two means it's going to let in more light it's got a forty two millimeter diameter it's all just simple math is how they figure out what this number is to be honest with you. What they do is they make their lands and they make it a certain size and then they know well that will be a one point two lands and so they almost kind of figured this out last in some ways we know what focal length now let's make it this big what's our aperture on it what about other lenses? Well a twenty four one point four let's in the same amount of light as a fifty but you'll notice that the opening on lee needs to be seventeen millimeters in size and that's because it's a very short focal length lens will you go up to a three hundred two point eight this is to stop slower so it lets in one quarter of the amount of light as the fifty but the opening needs to be huge because it is a very long three hundred millimeter focal length lands and so the length of the lens is gonna have a big determination of how easy or difficult it is to get light into that image sensor area. So with our prime lenses they are available in a wide variety of maximum apertures ranging all the way from one point to to a relatively slow five point six so there's a wide range that you can get with the primes and with zooms there's a fairly wide range as well not quite as wide there fastest zoom's the ones that let in the most amount of light are going to be these two eight two point eight apertures most common are going to be the zooms that have some sort of variable maximum aperture on it which means the aperture changes as you zoom lens back and forth a little bit at that maximum opening. They do also have some maximum apertures of f four that stay fixed therefore, but they zoom back and forth and those were some really nice lenses that I'm going to have some some nice things to say about later on in the class. Now you'll hear photographers talk about lenses being fast or slow, and what does that mean? And where is that cut off? Basically things above this dark grey little mountain in here are what most people would consider fast things below. It are going to be considered slow if you have a fifty millimeter lens that's f two that's not really going to impress your friends and neighbors that are into photography is being a fast lands it's it's pretty typical, but if you had a two hundred millimeter lands that was f two that would be considered very fast so fast lands depends on where it is on the scale of lenses your basic zooms we're talking about zooms that cell anywhere from one hundred fifty dollars to one thousand dollars. There are kind of on the lower end of the quality scale are going to be relatively slow lenses. If you want to buy the top of the line zooms, they're going to be faster, but there is a limit to how fast they can make them. If you want a lens that lets in a lot of light, even a basic prime lends a non zooming lens is going to get you a lens that is very fast. But there are a collection of really high end nice lenses from an icon that will give you some very fast apertures, but it will vary depending on what focal length you are. If you said well, I want a one point four lens that goes out to eight hundred, you're gonna have to wait because nobody makes when no one's even close to it right now, they don't make them, and so depends on the focal length as to what the maximum aperture can. Abby. Now you will hear photographers talk with great reverence about these fast lenses who have had eighty five one point four and it's the best. Why is it the best? Well, there's, a lot of things that go into these fast lenses that you may not think about right off the top of your head. The reason that they are called fast lenses is because they allow you to use faster shutter speeds, and that was kind of the first thing that photographer's notices. Well, we have this aperture well, now I can use a faster shutter speed, and this has a lot of long ranging effects. We could choose to use a lower I s so rather than a faster shutter speed that would be a valuable use of that extra light we will be able to shoot under lower light conditions or will be able to shoot with shallower depth of field with these lenses that are faster it will also result in a brighter viewfinder remember, what we see in the viewfinder is a direct result of what our lenses projecting into the camera and so having a significantly brighter lens can help us out in the viewfinder itself. In many cases it'll also allow our cameras which have auto focus systems built into them allow them to focus faster. There are autofocus sensing modules in the camera and the more light they have typically either the more accurate they khun b or the faster they'll be ableto work. And so if you have a two eight lens vs of five six lands I would good money that the two point eight lands is going to be able to focus faster on its subject than the five point six less and then in general they just tend to be built in better quality construction because they know a lot of pros or using these lenses and so they have wider focusing rings they have metal lens mouse there just have a lot of those better amenities that photographers come to appreciate as they use a wider variety of lenses so they have a lot of lenses that fall into this f three point five five point six aperture range this is most of their basic zoom lenses and these are great because they usually have a very versatile practical zoom range and so this is where a lot of people start out their photography I started off with two lenses in this general range and that's all I had and it was good until I kind of figured out what was important to me they tend to be less expensive they tend to be smaller and lighter in size and so if you're going to be using these, the things that you're most likely be using them on is just general purpose stuff maybe family photography or travel photography because there's a lot of different types of lenses that you might need for that type of photography and they're perfectly acceptable for that type of uses there are few linz is not a lot that have a maximum aperture of f four and they range between zoom lenses and prime lenses as well and so they're more affordable than the next ones. We're going to talk about which of the two point eight lenses they tend to be a little bit lighter and smaller and what's really nice on the ones that are f four is that you can zoom back and forth and if you set f or it stays there it doesn't switch to something else. So for those of you who have taken my advice from my fundamentals class and started to use a lot of manual exposure when you're out there setting your shutter speed, setting your aperture, you could get that whole exposure things set up, and then you can zoom back and forth for compositional reasons and you don't have to worry about that exposure changing. So I really liked, though, zooms that air at four or two point eight he's going to be good for travel, wildlife and landscape. A lot of people tend to really like these that force, and they're using them for this because they're a little bit lighter and a little bit smaller than the two eight lens we're talking about on the next slide. So f two point eight for me, that is kind of like go to number for serious photography. If you are a serious photog for chances are you probably wanted to point eight lands that was just kind of a great standard for all sorts of things because it allows us to shoot which faster shutter speeds to really stop fast action for sports photography for the portrait photographer it's gonna allow us to shoot in shallower depth of field so we can blur that background out of focus and it's very convenient for those zooms. Just to stay at two point eight the whole time. And so people who are going to be using this, they're going to be shooting action, a lot of sports wildlife events, whether it's a wedding or a corporate gig, where a lot of people are milling around or a trade show. Anything like that, where you got a lot of a little bit faster action where you need those faster shutter speeds. That two point is just a standard that the pros have. Next up are the really fast lenses. So f one point ford f two there's, a fair connect collection of these were out of the zoom range these air prime lenses. So when you really are under the very lowest light conditions and you are needing faster shutter speeds or extremely shallow depth of field, you could be using this kind of it's a continuation of the two point eight but low light portrait's event photography. So wedding photographer working in a dark reception hall gonna want one of these a news reporter whose assignment can vary from bright lights to really dim light areas to working at night time. One of these lenses can really saved the day.