Lens Considerations: Focal Length
We are gonna be talking first about lens choices, okay? And the one thing about lenses that may surprise you to learn is that it could be argued, it could be argued, that your lens choice is actually more important than your camera body choice. So if you were to say to me, "Khara, I have some money "and I want to buy a camera, "a new camera body or a new lens, "what should I do?" I'd be like, ooh, get a good lens and I didn't always understand that. When I first was giving in to all of these and people would be like, "Ooh, my lens this and my lens that." I would be like, why do you need all these lenses. That's ridiculous. You know, I thought you're just, you should be able to do it all with one lens. Well, that is physically impossible just physics and optics it does, I don't know. I suppose maybe someone could invent a lens that would do it all. I'm sure it would cost far more than anyone could dream but it's just not the way it works realistically. So, you use different lenses to ac...
complish different things so it can really affect your image. For example, you might choose one lens if you're gonna be shooting a landscape and you might choose a different lens if you were going to be shooting a portrait. So, what do you look for when you are looking at a lens? How do you compare one lens to another? What kinds of different effects does it have on your images? So, the first thing we're gonna talk about is called focal length. That refers to how closeup or wide the lens is able to capture. So, look at it like this. A wide lens is gonna capture a wide angle of view, so something maybe bigger, a bigger area like this and that's gonna be the lower numbers. So, we might typically say that a 50 millimeter lens is kind of a standard. It's closer to how we see with our eyes. 50 millimeters so something a wide lens would be usually a number that's lower than 50. So, like a 24 millimeter lens would be considered a wide angle lens. So that would be something along those lines. Whereas a telephoto lens is gonna be very narrow and the higher the number the more closeup you're gonna be able to see with that lens. And that's gonna be higher numbers, usually much higher than more along the lines of 85, 100, even 300 and more millimeters. So, focal length is measured in millimeters and here is an example of one scene shot with two different lenses from the same position. So this was at my local zoo and I picked a spot and I just stood right there and I got the widest lens that I have, it's a zoom lens, a 16 to 35 millimeter so I zoomed all the way out to 16. And I stood there and shot the scene in front of me and I circled the bird because you can't really see him. It's such a wide shot that he's very tiny. And then I took that lens off my camera and I put another lens on and this is a much more telephoto lens, a 200 millimeter lens. And from that same position on the ground I was able to get that much more closeup shot of the bird. And it looks of course in the photo on the left, it looks like he is so far away from me but that's kind of a funny thing that wide angles do, they make things look far away and bigger and all of that which is why people use them like in real estate photography to fit a whole room into the frame. And then when you get there you're like, oh, this looks way bigger in the pictures because the lenses can create a lot of distortion and they can sort of trick that concept but. So there you see the difference. The smaller numbers are further back wider viewed and the higher numbers are closer up. So that's the main thing. That's what we're talking about when we talk about focal length. Measured in millimeters, the numbers are smaller, big and it relates to how much you're seeing in that frame. Okay. When we look at the lenses then we can buy lenses with focal length that are either set as in a prime lens as here. This is an example of a 50 millimeter prime lens which means it's only 50 millimeters. It doesn't zoom, that's it. It's one focal length. That's what prime means. In this case, 50 millimeters or these are my two zoom lenses that I use all the time. I have a 70 to 200, that's this big one on the right. That's the one I shot the close up of the bird with, zoomed in all the way. So that goes from 70 to 200 millimeters and then I have my wide angle zoom lens which goes from 16 millimeters to 35 millimeters, still wide. So, those three lenses, the 50, the 16-35 and the 70 to, we would say 70-200, what we mean is 70 to 200 zoom lens. That covers my general range that I like to operate in but it really depends on what you're doing, what kinds of things you're photographing. I lately for the past several years I focus exclusively on weddings so I really needed this range to cover the venues, right? I wanted a wide angle so when I'm shooting like the ballroom or some crammed hotel room or wherever, I wanted to have the option to get a nice, good wide shot but I also need of course to be able to capture the ceremony from the back of the aisle somewhere so I need a pretty good zoom lens. And then my favorite lens of choice is my 50 millimeter, this guy right here. That's the one that's on my camera all the time unless then I'm like, I guess I need a wide angle here. All right, I'll take this. That one's just my favorite. I love my 50. But depending on what kinds of things you're interested in photographing you may have totally different needs. You know, if you're a wildlife photographer you're probably gonna have some huge lenses like then you're really looking for those really high numbers so you can get up close to see those animals. Or if you're a sports photographer you see those guys on the side lines where the lens is so heavy they have like a monopod for the lens and then the camera's just floating on the back. Those are not inexpensive those lenses, they're really heavy and really just physically big. So, what kind of lenses you're gonna need is gonna depend on what you're shooting. If you do a lot of people and stuff then you probably don't need some really wide angles. They're not so flattering in portraits, they can be cool. I mean, I've shot some cool portraits with wide lenses and you would use those a lot I would think with like editorial photography and stuff like that where you're capturing someone in their environment, so you would need a wider angle. But if you're doing just straight up like headshots or something like that, you probably wouldn't need to spend money on a wider angle. So, it really just depends what kinds of things you're shooting but for landscapes you'd probably want a wider lens. Anyway, the effect of the lens that you choose, it can really make a big difference in your photos. So, not only of course as we saw here, I mean compositionally speaking we're either like seeing, barely seeing the bird which is so tiny or we're getting a nice shot of the bird so there is that. And I don't remem, I think these were both shot at f/2.8. So, here is another good example of how even though 2.8, that's an aperture setting and that is what controls your depth of field, when we're talking about such a wide angle, a 16 millimeter, the 2.8, the effect on the depth of field is really reduced. But at 200 millimeters shooting at 2.8, look at that yummy, blurry background, right? That's so delicious. So, those are both at 2.8 from the same position. Then this photo, this collection here, these are shot, one's at 35 millimeter so quite wide. The other at 200, also both at 2. but what makes the background look so different is the long lens and these I had to change my position, right? Because if I had stayed in one place and saw the same scene with these two different focal lengths they would be like the picture of the bird at the zoo. One would be really wide and one would be close but I wanted to be able to compare backgrounds equally so I changed my positioning so that the composition would more or less be the same. But you can see how the tree stumps and everything looked much closer to him, this is my son again. They look much close to him over here at the 200 millimeter focal length than they do at the wider one because of compression. So, the more telephoto lenses also have this thing called compression where they make the scene look more compressed this way, like depth-wise. So the background appears closer to him than it does over here. Kind of interesting. And this was sort of a tricky thing to set up so I had to get really up close and in his face at the 35 millimeter and then I had to back away far at 200 millimeter to try to get the same composition with two different focal lengths. So hopefully that makes sense but you can see that the background is not just more blurred but it actually looks closer. So it's kind of an interesting thing. Some people have heard about what's called the cropped sensor on your camera. So when you're shopping for lenses it would be simple if a 100 millimeter lens was always 100 millimeter lens. But in our world of technology and cameras that's not the case. So, you may have a camera that is called, it's called a cropped sensor camera and that simply means that your sensor is a different shape. That's all it really means. But the effect that that has when it comes to your lenses is that what might be on my camera and behave like a 100 millimeter lens, that same lens if we put it on your camera if you have a crop sensor it would behave as if it's for example maybe 150 millimeter lens which could be to your advantage, right? So, if you are someone whose photography interest would really make you want a lot of telephoto power, I'd say get a crop sensor camera because then that 200 millimeter lens might be more like a 350 millimeter lens on your camera. So, that's called a crop sensor. And here's what's happening in those cases. It took me a long time to really wrap my brain around what this, how this happens and why but if this circle is the lens and what the lens is seeing, the sensors on our cameras are basically rectangles. Some are longer and skinnier and some are shorter and fatter and all of that. So they come in different shapes and sizes. So, this orange shape, this orange rectangle represents what would be called a full-frame sensor so like my DSLR is a full-frame sensor. It's similar to 35 millimeter film back in the day. It's based on the 35 millimeter film. So, that's also what the lens focal lengths are based on. When you are shopping for lenses that's what that number is on a full-framed camera, okay? The orange rectangle represents what would be seen on a full-frame camera while the yellow one represents what a different camera, the same scene with a smaller cropped sensor, that's what that camera would see. So, it appears closer. It looks like it's a more closeup photo because of just the way the optics work in that camera body. Does that make sense? That's how, how that can be different. I just couldn't for the longest time I was like I don't get that, I don't understand why that happens so I wanted to try to make a little bit of a graphic to help people at least understand what's happening. The cropped sensor cameras are basically just, they're seeing a smaller piece of the whole picture and therefore, it looks cropped in. So it appears larger and that's why we call it a cropped sensor. The factor by which it varies, it varies from camera to camera. It's usually about 1.5 times more but it could be 1.3, it could be 1.4, it could be whatever and that's always in the documentation. So when you are shopping for cameras they'll tell you like, oh, it has a cropped sensor with a ratio of like 1.5 or something and then you kind of have an idea of how that works. And then you'll just know if you're buying 100 millimeter lens it's gonna act like 150 millimeter lens on your camera. So, that can be an advantage when you want the focal length. If you're looking for a wide angle then it works against you because you'd have to have a super wide lens to get maybe the actual wide angle that you want. So, that's that. On a point and shoot it's a whole other ball game, okay? On a point and shoot in this example we have this PowerShot ELPH and the number is printed right there on the front of the lens. Obviously in a point and shoot you can't change the lens, it's built into the camera. So when you're shopping for the point and shoot you are at the same time shopping for the lens. So, you'd wanna know what kind of zoom you're getting. So, it's gonna tell you on the lens, physically it will say something like five to 40 millimeters and if you're thinking about what I just told you in terms of how that would be wide angle or telephoto, you'd be like that's crazy wide angle. That doesn't even make sense and it does sound like that. But with point and shoots it's a whole different scale. So, I don't know how this, I don't know why this stuff just doesn't all get converted. I'm gonna try to trust that there's a good reason behind it that I'm not aware of. So, nobody converted it on the front of the lens, it says five to 40 millimeters which kind of means nothing to most people. It doesn't mean anything to me because it's point and shoot scale. But often when you shot for point and shoots, in parenthesis it will then have the 35 millimeter equivalent. So, the 35 millimeter are equivalent of this five to 40 millimeters is actually 28 to 224. So it's hard if you're shopping for point and shoots, in my mind I'm like, I don't know what five to 40 millimeters would like be like. I don't know what kind of focal length that is. But then if I convert it then I'm like, oh, so 28's a pretty good wide and 224 is a really good telephoto so this lens has some pretty great zoom. So then I can make an informed decision. So you wanna make sure if you're shopping for point and shoots you wanna get the conversion or on our phones we have, well we have the digital zoom and not the same thing and we'll talk to that in a minute. But on the point and shoot here, so it's sometimes measured like this like five to 40 millimeters or sometimes they just tell you because those numbers don't mean anything to a lot of people. Sometimes they'll just say, "Oh, it has eight times zoom." Eight times optical zoom. So you know that you can get eight times closer than when you started I guess. So the higher the number there the more area you can cover in your focal length, okay? So, that's what it says over there in the corner, eight times zoom but you'll notice it says eight times optical zoom because there's another thing about point and shoot cameras that they try to sell you on called digital zoom, wah, wah, and I put a big thumbs down (lips vibrates) because it's as the British would say rubbish. It's just rubbish. That's a fun word I think we should all use more. So that is total rubbish. Here's what's happening. When you use optical zoom you are photographing your image with the optical components of the lens. Nothing is being, I wanna say inflated but that's wrong. Nothing is being manipulated, it's all just like true, okay? When you turn on your optic or your digital zoom you're taking the farthest optical zoom you can get and it's literally enlarging it on the camera sensor. So, this is an example of a lighthouse in Michigan, I have to think for a second, and from where we stood on the pier and this was, I don't remember what camera. It must have been my point and shoot obviously. So, I zoomed in as far as I could get with the optical zoom and then that only gets you so far. But if you continue with digital zoom you'll get closer but it might look like this when you go to print it because what's happening is it's just blowing it up on the sensor and it really is, well, here's what it really is. (chuckles) It's not good, okay? So, (laughs) there, we'll show that, yeah. And we see this all the time, it's perpetuated like the idea that it's okay, it's perpetuated in television and stuff because we see especially like my beloved Law and Order does this all time where they'll be like, "Oh, we can't quite make out "who the suspect is. "We have this grainy, bad footage of them at the ATM." And then they bring it to their tech people and they're like (mumbling) and then it zooms all in and it looks like poo, right? It looks like rubbish and then suddenly their computers are like oh, we can clean this up (mumbling) and then it all gets crystal clear and then, you know? I always say like, oh, then they can catch the guy because his name's tattooed on his neck or something. (laughs) It doesn't really work like that. So if you enlarge the image on the sensor just like we talked about in the previous segment about resolution, it doesn't work well, it just falls apart. So you're gonna start to see pixels. And digital zoom you can feel it on a point and shoot if you've ever been like zooming in and the camera is like, (buzzes) and then it stops, for a moment it pauses and then it continues. That second (buzzes), that's the digital zoom and often times on your display you may not notice this but if you look you'd probably see that actually it changes color. Like the little icon that tells you you're zooming would change from like green to red, like something visually will indicate that you've crossed the line somewhere. And it's basically telling you this is crap but okay, if you want it I'll make you happy. So I would just suggest turning that off. So in your settings usually there's a way to cancel your digital zoom so you just can't even do it then you don't have to worry. But it is, it's just garbage so you don't want your pictures to look like that. Okay, so optical zoom is where it's at. Don't buy a camera because it sold you on 40 times zoom, digital zoom. You want optical zoom, that's all that really matters.