Lessons

Lesson Info

Sensor Sizes: The Basics

Let's talk about the sensor. It's a continuation of section one on the camera, but there's a lot of information going on here, and there's a lot to talk about. So inside of all of our digital cameras, if we were to take off the lens, and look behind the mirror, if we happen to have that. Behind the shutter is the sensor. And this is what is recording light in lieu of the old days of film. The sensor. What is the best sensor in the world? What is the most perfect sensor that we could possibly imagine? Imagine we were designing a new camera here, and we were trying to design the most perfect camera in the world, and we're working on the sensor right now. Some of you might say, well we should have a lot of pixels. More pixels. Whatever the other competition has, we want more pixels on our sensor. That's gonna give it more resolution, and that would be nice to have. But some of you might smartly argue in the opposite direction. We should have less pixels. Because those pixels will be bigge...

r in size, and will be able to be better working under low light conditions. And that's a debate that can go on forever, whether more or less is better. Another option is that we could have a bigger sensor. A bigger sensor means we've got more room for more pixels and bigger pixels at the same time. That would make a really, really high quality image, is having a huge sensor. But you know what, a huge sensor makes the camera bigger, it makes the whole system more expensive. Maybe we should make a smaller sensor, so we could have a more portable, convenient camera to use. Another option that we could go for, in trying to get the best sensor out there, would be better color. And there's pretty much no one that's gonna be arguing about worse color; we all want better color. And so that's a no brainer. Unanimous vote there. As well as we want a greater dynamic range. We wanna be able to see into the shadows, into the bright highlights, as well as possible. Something else we'd wanna look for, is something with faster processing. And so this kinda goes along with the sensors. All that information needs to get processed and put onto the memory card. We want that to happen as quickly as possible so that we can shoot and do a lot of things with those images. And then we, of course, we want something that has less cost. Now the problem is, is that I would like all of these things in my next sensor. And obviously these things conflict with each other. You can't have a bigger sensor at less cost under most situations. Just not gonna happen. And so you've gotta start making these compromises. So there is no perfect sensor. They're all getting better and better. And you just need to find one that fits your needs. So let's take a closer look at what we have going on here. So the first thing, and we talked about this very briefly before, is the sensor size. And this is something that you should absolutely know about your camera. And so we have different sensor sizes that have different capabilities. And the largest of these is based off of the old standard 35mm film. Now what is magic, and wonderful, and perfect about 35 mm film? Nothing. It just happened to be really, really popular. And so it's the standard that a lot of us kind of put out there as, "Okay, yeah, I know what that is." And so when digital came around, a lot of us who were shooting photos said, "Whoah it'd be really nice to have a full frame camera so that all my lenses do exactly the same thing." The problem was, is making those sensors at that time, and even now, is still a relatively expensive process. And so the camera manufacturers made a smaller size sensor called APS. And other manufacturers chose slightly different sizes, according to their own needs and capabilities. And so we've ended up here today with cameras of many different size sensors, and this affects the type of lenses that we use on them, and the type of results that we're gonna get from them. And so they go by a lot of different, unusual names, which really troubles me. Because sometimes they're words, sometimes they're letters, sometimes they're numbers. And if you're new to photography, and this doesn't make a lot of sense, I'm with ya. It doesn't make any sense, and I don't like it at all. And one of the things that I dislike about this entire thing, is that it's extremely misleading. Alright, so this Nikon camera uses a sensor called a CX sensor; that's Nikon's name for it. But in the industry, it is commonly called a one inch type sensor. You know what one inch type sensor means? Not one inch. It's a "like" it's a one inch sensor. If you were to actually measure a one inch type sensor, what you would find is it's 9mm, and 13mm, heighth versus width. Now an inch is 25mm, for those of you who kind of forget your little conversion chart there. There is nothing one inch about that sensor. It has to do to a very old standard about making picture tubes back from the 1930s, 40s or 50s or sometime in that era. And it's about how big the actual tube needs to be before the area behind it will collect light. And it has nothing to do with the way we deal with modern sensors. And so it is completely misleading, and so when you see these numbers up here, these are all just flat-out lies from the manufacturers. Just complete lies. Now the numbers I put in blue here, these are accurate. Because I like to be as accurate as I can be, alright? And so, I think this naming system has got to go, but I'm not in charge of the photographic world, but I'm in charge of this class so we're changing the names in this class. And so I think sensors should be measured the same way we measure our TV sets and our computer monitors, with a simple number going from corner to corner. It makes it very simple. 43mm is a full frame sensor. APS is 28. And it's a whole lot easier to compare 28 versus than it is full frame versus APS. How big in relevance is one to the other? And so your phones are gonna have something like a little 6mm sensor. The big fancy cameras are gonna have somewhere around a 43mm sensor. And so this is terminology that you're only gonna find in my class. And so you still need to remember these other names because that's what everyone else in the world uses. But I think it's easier to understand what these are. Now if you know what size sensor you have; let's say you have a full frame camera, you have a 43mm sensor. Here's a great rule of thumb when it comes to lenses, is that if you take your sensor size, that is pretty equivalent to a normal lens. And so if you have a full frame camera, 43mm lens is a nice, normal lens. If you have a four thirds camera, a 22mm lens is a very normal, focal length lens. It has a normal perspective to it. If you were to divide your sensor size by two, that would make for a very nice landscape or wide angle lens. If you take your sensor size and you double it by two, it becomes a very nice portrait lens. And so if you're wondering what would make a good portrait lens; if you asked me the question-- Don't do this, because I'm gonna answer it for you. John, what would you recommend for a portrait lens? I would say, "What sensor size do you have? Let's double that, and that would make a nice lens." And so for full frame, 43 times 2 is 86. You know what, one of the most popular focal lengths is 85mm. Take that down to four thirds, that you end up pretty close to 50mm, and that makes for a very nice portrait lens there. Alright, you take your sensor size, you multiply it by four, that's gonna be a pretty good lens for a lot of sports and action type work. Depends on how far away your subject is, but in general, this is a rule of thumb. And if you were to take your sensor size, multiply it by eight, then it becomes a pretty good wildlife lens for something that's really far off of there. How big a lens do you need? And so, with full frame, that's gonna be around a 400mm lens. And so that's just kind of a simple way. And so when we start talking about lenses, which is the next big section after sensors, we need to talk about sensors as well. So this is a topic that we will continue talking about and discussing in the class. So we're gonna get rid of these little tiny ones because we're concentrating on the more serious cameras in this class. The ones that use the slightly larger size sensors. And so these are the most common of the cameras that you're gonna find with interchangeable lenses out there. The crop factor over here on the left on the Full Frame, is 1.0, which means it's the same size as 35mm film. Canon, Nikon, Sony, Leica, and someday soon, Pentax will have cameras that work with that full frame sensor. The APS is a smaller size sensor used in a lot of the manufacturers. The C version of it is used in Canons. And how did we get this crop factor of 1.5? Well we go back to these numbers, 43 and 28, and we can either divide, or we can multiply by various things, and we can end up with these numbers running back and forth. So it's just a mathematical formula. What area did we crop into, or what do we need to magnify to equal the other area. Canon is the only one using the 1.6. And then there's Olympus and Panasonic who are using the four thirds system. So know what camera you have, know what sensor is in your camera, because that's gonna have a strong impact as we go forward looking at what lenses are in the camera. Now what's the big deal with different sensors, different size sensors? It's that we can put different lenses on 'em. And in this example, we have a Full Frame sensor. And we have an image on our Full Frame sensor. What if we were to shoot this exact same photo from the exact same location, with a different size sensor? Everything's the same, we're just gonna swap out the sensor. Well tell you what, let's swap out the sensor in this camera, and put in a smaller size sensor. Now, what has changed about the photograph? Clearly we have cropped in on that photograph, and we have lost the outside edge. And it is no longer exactly the same photograph. It's got a lot of the same stuff in it, but it's not exactly the same. There is a different angle of view that's happening to it. And so this is what talk about when we talk about crop frame cameras, is that they have an image that they are collecting kind of in the middle of where that full frame would have normally cropped it. Now this image was actually taken with a 16mm lens. And if I wanted to get this, which was taken with a full frame sensor by the way, and I wanted to get the exact same image on a crop frame sensor, I could do it. But I would need a different lens. In this case, I would need a 10mm lens. And the reason I know I would need a 10mm lens is because I can do just a little bit of math. And so the math is pretty easy. 10mm times 1.6 is 16mm. And that's what I used over here. And so two photographers standing side by side can get the same shot with different lenses because they have different size sensors. So this is why it's important to know the sensor, because then you're gonna need to know that for choosing the right lenses. Now, early on in the age of digital, this was a major disadvantage for the crop frame sensors. Because you lost your wide angle capability from your full frame, and there was little to know lenses that would give you the equivalent 10mm. But now the manufacturers have made several more lenses that will go down this wide. But there are still many more choices when it comes to the full frame. And we'll talk more about that later on in this section. Alright, let's try this once again. We're going full frame. We're capturing an image using the entire imaging area. But in this case, most of our information is right in the middle of the frame. We don't need all the extra information around the edges. So if we were using a crop frame camera with the same lens, that image is going to be concentrated on the pixels in this area. And this is actually the preferred image, because we are filling the frame with our subject. And so these crop frame cameras have more of a reach, and they have an advantage when it comes to telephoto needs. And so very good for wildlife and sports photography having these crop frame cameras. So if you wanted to capture that image, you'd need something like a 300mm lens, on this crop frame sensor. Nine inches length, two and half pounds, $1,400. And you're thinking, "How much would it cost me-- What would it take if I wanted to do this with a full frame camera?" 'Cause I'm guessing a lot of you have crop frame cameras. But a lot of you are probably lusting after full frame cameras. You really want those bigger sensors. Well, let's do a little math. We want the same image on that size sensor. So we started with a 300mm lens. We have a 1.6 crop factor. We're gonna need a 480mm. Lucky for you, several of the manufacturers make 500mm lenses. It's gonna be twice the length, three times the weight and seven times the price. And it will be a better image. How much better? Well, you would have to be the judge of the quality on that. It's a little bit better. But it's gonna cost you a lot to upgrade. And so the full frame sensors are great, they're wonderful, they're fantastic. But there is a price to be paid in weight, size, and dollars in order to get that. Especially in the telephoto range. So it is better in many situations, but it's a bit of a compromise as to what's actually best for you in what you do. Full frame sensor is not the largest sensor that you can get. Just in case you're thinking full frame is the end all, be all of it all. Leica makes a beautiful-- We don't really have a name for this sensor, but it's 54 compared to 43, so it's a bit larger in size. And they have some wonderful image quality that you can get out of that. We can go up a little bit higher. Pentax makes a 645 camera, which shoots with a larger size sensor yet. We're up to 55mm in size. Hasselblad has one that goes a little bit larger. And PhaseOne just introduced a 100 megapixel camera that has an even larger size sensor. So depending on the size of your pocketbook and your budget, you can continue to go up in size. And you know what, this isn't the largest image size you can get yet. If you wanted to, now granted it's gonna be a little bit harder to find a digital back for a four by five camera, but the imaging area of those old landscaping photographers who shot these cameras, that's 162mm. And they made this in larger sizes like an eight by ten. That's gonna be 320. So any thinking that full frame is the end all, be all of everything, it's just one stop along a long continuum of choices that you can make in choosing a camera. And so, just one simple choice. Alright, so that's the quick briefer, if you can call that quick. I'll hide sensor sizes in some of the importance. Now this is not the last that we're gonna talk about this because this affects the lenses that we use, and so we're gonna bring this back up in the lenses as well.