Sensor Size: Basics
So the sensor in the camera has a huge impact on the final image and there's a lot of different things going on and this is the time to talk about those different aspects. So we're gonna talk about the size of the sensor. I got lots of comparison photos shot with different size image sensors. And then we'll get to pixels and setting the ISO, which is what we're gonna be doing ultimately in our camera all the time. Alright, inside your camera behind the lens, if you have an SLR behind the mirror, behind the shutter in there is the image sensor to your camera. And this is the all important mighty piece in the camera recording the information. Now there's a lot of arguments and debates as to what the perfect sensor is because there are different needs that different people have. And you'll see that some people argue that you should have more pixels and other people argue that you should have less pixels. And we'll talk about why that is as we go through this section here. Some people thin...
k a bigger sensor is better and other people think well no, a bigger sensor means a bigger camera and that doesn't work for me. So some people want a smaller sensor and so the camera, the sensor is kinda like automobiles. Some people want and need to drive a big truck and other people just need a little tiny car to get to work and back and they don't need to carry very many things. So it's personal according to your needs. We all want accurate color. We all want a greater dynamic range. We'll talk about the dynamic range, which is the range of brightness that your cameras can handle. Of course it's good to have faster processing so that it can process all those images very very quickly. And that's part of the sensor as well. And it's of course, good to have things that are low cost. Now there's gonna be a lot of compromises. In this as well as a lot of other things in photography. And it's a matter of really knowing what's important to you and how you wanna use a camera and the results that you wanna get from it. So let's go back and talk about sensor size. We hinted at it a little bit earlier. There's different cameras. There's different size sensors and it plays a large part into what they can do, what their best attributes are, and a big part into the types of lenses that you can use with them. So with the sensor, the most popular size for quite a while was 35 millimeter film. And that was because 35 millimeter film was this happy medium of a film that was large enough that we could make, say a poster size enlargement, but it was small enough that we could walk around Europe for weeks on end and we could have a bag full of interchangeable lenses. It was just a really convenient size. Now of course, they made cameras and film that were smaller and bigger but this was the happy medium. So when we transition from film to digital, all the serious photographers said I want a sensor that's the same size that I currently have so I can use all my lenses, which is where a lot of the money ends up being spent, is on the lenses not on the cameras. So, that's where many of us wanted to go, but it's difficult to make a large sensor. And that's considered a relatively large sensor. So they started making sensors that are smaller in size. And so you'll find a lot of cameras out there that have the smaller APS-C sensor. Now APS-C refers to a film that was based in the 90s, and I'm actually gonna talk more about that, comparison to full frame. Nikon, Canon have slightly different sizes, which we're not gonna worry about right now. The micro four thirds system from Olympus and Panasonic are using this smaller size sensor yet. And then there is these one inch sensors and all these compact cameras that have really small sensors and then down at the very bottom of the list, you have your phone. Your top of the line new current phone is gonna have the smallest sensor on it because it's a really small device and it has to be kept small. Now, I hate the names of these sensors. We have words, letters, numbers. Pick one and go with it. And that's just where the industry really isn't controlled by any one person. But if I could change one thing, it would be these ridiculous names that somebody who's new to photography makes no sense. Imagine if the engine in your car, well this is a 450. And that's the platypus car. And that's the XYZ car. It's like, well how does that compare. And so I think looking at the actual size of the sensors would be better. To tell you how ridiculous this is, a one inch sensor which is being used in a lot of the high end point and shoots, it's called a one inch type sensor. And what that means is that it's nine millimeters in height, 13 millimeters across, and 16 millimeters diagonally. Can anyone tell me where the one inch comes from? It's not from the measurements of the sensor. And it's called a one inch type sensor in the sense that this is a cheese food. It's not actually food, but we call it cheese food to let you know that you can eat it. It's not a one inch sensor, but it goes back, it's a long story we're not gonna get into. It goes back to TV tubes and what type sensors needed to be used in a TV tube for a certain size. And so this is considered a one inch type sensor. Nothing one inch about it. Completely misleading. It is not one inch in any dimension at all. And it's just misleading what some of these names are. And so, if I could change something in photography, it would be the sizing of the sensors. We would measure it like any other conventional thing that we do. Let's just measure it diagonally like our TV screens or our computer screens. And now we can reference, oh this is eight, that's 16. I know what that difference is. 28, 43, okay I have an idea of what the difference is between these. Now, there is kind of a little secret formula if you know what size sensor is in your camera, to figure out what lenses do on your camera. And I'm not gonna talk officially about lenses in a moment, but I know a lot of you already know things about lenses. And here's a rule of thumb when it comes to your sensor size. If you have a lens on that is about the same number as your sensor size, that's gonna be a normal lens. If we go to our full frame camera, 43. 43 millimeters is a normal lens. Round that up to 50. That's a normal lens for a full frame camera. If you were to take your sensor size and divide it by two, that would make for a very nice wide angle landscape lens. With our full frame user 23 or 43 divided by two gets us around 21, 22 millimeters. Yeah, that's a pretty good solid wide angle lens for it. If you have a smaller size sensor like in a four thirds sensor, you're gonna need an 11 millimeter lens for a nice wide angle lens. If you wanna shoot portraits, 43 millimeters times two is 86 millimeters. Most people's favorite portrait lens is an 85 millimeter lens. And so this works no matter what size sensor you have. You wanna multiply by four, that's probably gonna be pretty good for a lot of different sports photography. You multiply it by eight. That's probably gonna be a pretty good wildlife lens. And so if we were to take out full frame, let's just round it up to 50 for simple math. I like simple math. 50 times eight gets us up to 400 millimeters. That's a good place to be for a lot of wildlife photography. So sensor size will affect lenses. And we're gonna talk lot more about that in future sections. Now I have found that most people who are getting into photography and wanting to learn how to do manual generally are using these four different sensor sizes. Anything from full frame, the APS-C crop down to the four thirds system. If you want a full frame camera, you can get 'em from Canon, Leica, Nikon, Pentax, and Sony. There's some very good options. They tend to be a little bit on the spendy side because these larger sensors are more difficult to manufacture. The smaller size sensors. This is probably where I have more students than anywhere else. Shooting on this 28 millimeter APS-C sensor. Fuji, Leica, Nikon, Pentax, Sony. These are all making a lot of different cameras. This is kind of I don't know, the bread and butter. This is the heart and soul of where most photographers have their cameras these days. Canon is, well actually we should mention, 28 millimeters 43. Why do we call it 1.5 crop? I'm gonna talk more about it, but it's the relationship between 43 and 28. If you multiply 28 by 1.5, you end up to 43. And it's the relationship between the two. And this is important because 35 millimeter film was the most popular film of all time and it's kind of a standard that we adhere to. So we like to have a common standard that we can talk about when we go talk about lenses and angle of view and so forth. The Canon, they chose just something a little bit different. It's 1.6. It's kinda the same thing as the 1.5, but just a tiny bit smaller. And then the four thirds is notably smaller at a two times crop factor here. And so they're working together on their own system right there. Now the sensor size and the difference between them is one of the most confusing things to new people in photography. And it's confusing because well, it's a little bit odd. And why does everyone have to adhere to one standard? And so, let's think about it this way. We have a full frame sensor. We're capturing an image on our full frame sensor. And that's all well and good. But what if we don't have a full frame sensor? What if we're shooting this with the same lens in the same position with a cropped frame sensor? What happens to the image? Well, we're using a smaller sensor. And it's this area in the middle. And is this the exact same shot as the previous image? It's similar. It's of the same thing, but it's not the same shot 'cuz we're getting a different angle of view 'cuz we're using a smaller size sensor. And so lenses and sensors are very much related. And you need to know one before you really wanna start talking about the other in some ways. Now this was originally a problem on the early digital cameras 'cuz we didn't have really wide angle lenses for these new small sensors. We had wide angles for the full frame. And if we wanted to do it on a cropped frame, well it took a while for the manufacturers to start producing lenses. But finally they have produced a good number of lenses in order to get the same shot with a cropped frame sensor. So yes, you can get the same shot with a crop frame sensor. But because you have a different sensor, you're gonna need a different lens that has a different number to it. Now you're gonna need a 10 millimeter lens in this case because 10 times the crop factor of that sensor gets us to 16 millimeters. And I know some of you right now are probably saying what. Don't worry. Hang with me. We'll get this figured out. And so different sensors need different lenses. That's the main thing that you need to know about. Now as I say, in the early days this was a real disadvantage for the crop frame sensors. They didn't have a lot of wide angle options. They still don't have as many as you do in full frame now, but we'll get to that. They are there and they can do the job. But there was a secret advantage of these cropped frame cameras. Alright, so let's go out and shoot some wildlife here. So we got a wild tiger in India with a full frame. That's a nice little shot there. What about our buddy next to us who has a cropped frame camera with the exact same lens? What are they getting in their photograph? Well they have a smaller sensor. Same lens. Their tiger is gonna fill up more pixels on their sensor. And this is gonna do a better job 'cuz you're using up those pixels on a sensor, which is good. And so it's not the same angle of view because we have a different sensor in there. And so to capture that sort of image, you're gonna need something like a 300 millimeter lens. Alright, that's a big lens, but you know, that's something that can be doable by a lot of photographers. And as we talk about sensors, I know some of you, I know a lot of you probably own smaller size sensors and you're gonna be thinking wow, maybe I really need to up my game and get myself a full frame camera. Well when you get a full frame camera, you need to upgrade your lenses as well. So let's check in with our photographer who shot with a 300 millimeter lens on the crop frame and figure out what they need to do to upgrade to full frame now. Alright. You can get the same thing on full frame, but here's what you need to do. Take your lens, multiply it by the crop factor, and you will get the new lens you need to go out and buy. And lucky for you, they make a 500. Okay. It's twice the length, three times the weight, and seven times the price. And you can do the exact same angle of view, but it'll be a little bit higher quality. Now how much of a difference is there between these two? Well that's hard to quantify. But it's not a lot. It's some. And if you're competing with other photographers and you're like, ah man I'm trying to compete with Sports Illustrated on getting the best photograph, well that's what they're using 'cuz that's the best equipment out there. And so if you're trying to compete with the very best out there, well you gotta use bigger guns against bigger guns. But personally this might be a lot easier to work with financially, weight wise. And so there are advantages to both systems. Personally I own both systems because there are advantages to both systems and you can work with them back and forth. You can get really good results with a lot of different size sensors. Now, full frame kinda sounds like that's the end all be all of everything. That's as good as it gets. Boy I hope for a full frame. Well in photography, you gotta be really careful about climbing the quality ladder because it gets really steep and really expensive as you get up there. So full frame is just the same as 35 millimeter film. There's nothing special about it these days. In fact, it's kind of quaint and antiquated that we're basing our cameras on film people shot 20, 30 years ago. If you want, you can get into medium format cameras. Alright. They have larger size sensors. Alright. Leica system. Fuji recently introduced a nice little system. Hasselblad, they have a great system. Pentax has another system that's been around for a long time. These are players that have been in the medium format world for a long time and they have larger image sensors. Which means you're gonna get better image quality on them. Cameras cost three times as much as do the lenses, but you know if you want better, you, oh you guys still want better. Okay, well we'll go up even larger. Hasselblad just introduced a camera that shoots at 400 megapixels. Alright. These cameras can run close to $50, lens not included. Alright, you know, three to 10 grand per lens. And so there's always another step up if you wanna spend that money. Now, there's all sorts of downsides to these larger cameras. The lenses are larger. There's less options. There's different shutter speeds that are available depending on what you're doing. And so commercial photographers on high end shoots are often times using these higher end ones and as great as they are, we're not gonna be addressing them for the rest of this class. Most of the people are not using these, but yes I do wanna acknowledge that they're out there and you can always keep sliding up that quality scale. And we're all gonna have to come a point where you know what, this is where I'm happy. And somebody's gonna come along and say oh, but you can do more. Yes, but it comes at diminishing returns. How much better is one of these than at $60,000 than a $10,000? It's a little bit better. Maybe a fair bit better in some special situations. You wanna get bigger? Well, they still make four by five view cameras if you wanna put film in them. Haven't figured out a way to make a sensor big enough to fit on the back of this, but if you want a larger image area. 43 you thought was a big image area. We're now up to 162. They make eight by 10. And yes they've gone beyond eight by 10. But this is kinda the largest of the standard sizes. This is something like Ansel Adams used to use here. Large image area. But we can now get very very high quality images in a full frame sensor. And so for most of the photographic world, it's gonna be on one of those intermediate to kinda larger size sensors that you're gonna be working with. So first thing to know is what do you have in your camera right now. And if you don't, go google it, look it up, find it in your camera. It's usually not listed on the front or on the bottom of your camera, but it was part of the literature when you bought your camera. So first thing, figure it out. And then follow through with the rest of the class to figure out how good that is at different things, but.
John, we did have a quick question from Steven who said about the different raw sizes for some cameras that has the large raw, the medium raw, small raw, does that do anything differently with your sensor when you shoot in the different formats?
No, that's a good question because what happens when you shoot in, let's call it a medium raw. What's gonna happen is it's gonna capture the entire information in the sensor and then it's gonna reduce the file size by whatever it needs to to fit that number. So let's just say you have a 24 megapixel sensor and you can reduce it down to a 12 medium. It doesn't crop it. It just takes the file size and gets rid of and combines the data and basically down samples it to the appropriate size. And so, if you know you don't need the extra data, the lenses and everything else in your camera is gonna act perfectly normally.
About the raw piece, does the sensor size impact the amount of recoverable clipping based, you know when you go into that raw? So is the raw from a micro four thirds different than the raw coming out of your larger sensors, your full frames?
In theory, yes it is. Because what generally happens and this gets to our next section, is that bigger sensors generally, not always, but generally have bigger pixels. Bigger pixels are better at recording a variety of light levels. But this can vary according to the manufacturer and how good a sensor they have and technology. Technology changes and there are some cameras that are micro four thirds right now that shoot better than full frame cameras from a few years in the past because new technology has come forward. And so there's a number of variables, but in theory the bigger is better. That generally holds true with equal settings of everything else.