Skip to main content

photo & video

Camera Buyer's Guide

Lesson 6 of 16

Sensor Size

John Greengo

Camera Buyer's Guide

John Greengo

buy this class


Sale Ends Soon!

starting under


Unlock this classplus 2000+ more >

Lesson Info

6. Sensor Size

Lesson Info

Sensor Size

The next important topic is sensor size. Once you start looking at these cameras you will realize that sensor size is a very important issue because there are a lot of different sensor sizes in these cameras and it has a big impact on the cost of the camera and all the features that you can use. So to understand these it's probably easist to talk about the largest of the common sizes. Which is known as a full frame sensor. This is based on 35 millimeter film. And 35 millimeter film was extremely popular in its day because it was just the Goldilocks right size. It was small enough that it could fit into a small camera, big enough that you could make a good enlargement from it. So as we moved into the world of digital, it was very convenient just to add a digital camera and use all your existing lenses on it. But those sensors were very expensive so camera manufacturers made smaller sensors in smaller cameras so that they could be more affordable and be smaller in size. Now they use a va...

riety of funky names that I'm not fond of and I'm not gonna get in to right here. But they do have a variety of different sensors out on the market. With different sizes you can see them listed there in millimeters to give a better idea of what they are. So I think a better way of measuring them would be just to measure them from corner to corner. It's a lot easier to compare from one size to the next. When we're talking about interchangeable lens cameras we're talking about these cameras that have the larger sensors which give them the greater capabilities 'cause they tend to do better with light. A lot of manufacturers are making full frame sensors that have what's called a crop factor of 1. which is to say it is exactly the same as 35 millimeter. In order to make more affordable and smaller size cameras some manufacturers have chosen to make a 1.5 crop sensor camera that crops in by a factor of 1.5. And that's how we get the 1.5. It's the relationship of 43 millimeters to 28 millimeters. Slightly smaller Canon chose 1.6. It's basically can be grouped in there with the 1. but it is slightly different. And then there are a couple of manufacturers, Panasonic and Olympus that specialist in making even smaller size sensors so their cameras and lenses can be even smaller in size. And so being aware of this crop factor is important because there's all these different photographers and they're using different formats. But we're trying to share information about lenses and techniques. And so we kind of all revert back to the full frame sensor in order to speak in a common language. So if we take a full frame sensor in this case. And we capture an image. And what would happen if we used a cropped frame camera in that same location with the same lens? Well we would be using a smaller sensor and we wouldn't be capturing quite as much of the area from side to side. So clearly that's not exactly the same photo. And so in this case the full frame sensor is capturing a larger scene which is probably the better of the two options in this particular case. So this full frame image was captured with a 16 millimeter lens on a full framed sensor. If you did want to capture that same image on a crop frame sensor you could do it but you would need a different lens because you have a different size sensor. You would in fact need a 10 to 22 millimeter lens. Now how do we know we need a 10 millimeter lens? Well it's because of the crop factor and a little math. 10 times the 1.6 gets us to 16. So these lenses are equivalent in their angle of view. And so that can be important for people understanding when we're talking about lenses. Now you might think that's a disadvantage to having a crop frame camera. Well let's look at it from another perspective. We're photographing some wildlife or it could be sports photography where our subject is not quite filling the frame with a full frame sensor. If we use a crop frame sensor the pixels on our sensor are now more on that subject. We've got our subject filling the frame more. Which is a better image in my opinion. If you're trying to see detail in that particular subject. If you wanted to get this close up shot you would probably need something like a 300 millimeter lens. All right there's some of the stats on the 300 millimeter lens. Now if you do want to step up from a crop frame sensor to a full frame sensor you need to step your lenses up as well. So let's figure out if you wanted to get the same shot on full frame, what would you need to do? Well you started with the 300 millimeter lens. You have a crop factor of 1.6. That puts you at 480 millimeters. Well you're in luck because they make a 500 millimeter lens. Unfortunately it's twice the length, it's three times the weight, and it's seven times the price. And that's because telephoto lenses are very expensive to make and when you want to upgrade the sensor, you're going to have to upgrade your lenses. And so there is definitely a compromise as to what size sensor you use. You will find that generally in the photography world the people who write the books, the people who make the videos, the people who make the classes like me. The people who make the videos online, a lot of them use the full frame sensor. And it's what all the quote unquote cool kids are doing in photography. But the fact of the matter is that I have crop frame cameras and sometimes I choose them over full frame cameras because I think they do a better job at what I'm trying to do. There's a lot of different trade offs. When you upgrade to a bigger sensor, everything gets more expensive. It does get better quality. It also gets bigger and it's not right for everyone. So be aware that there's different size sensors and it's finding the one that's right for you. The bigger size sensors will in general have bigger pixels which are better at gathering light. For better image quality, better work under low light. They will generally have more pixels for those who need higher resolution. Overall they generally have better image quality. You do have to dig pretty deep into an image to see that image quality difference but it is there. And they are also better under low light conditions. And finally they are better with shallow depth of field. So if you're a portrait photographer you want your background out of focus and your subject in a really shallow depth of field, it's easier to do because of the type of lenses that you use on those large sensors. The smaller sensor can be put into a smaller size camera which means the lenses are also going to be smaller. The weight is going to be less. And you're going to be spending less money on these. And so as I say it's a compromise to figure out what is right for where you are. One of the biggest challenges is trying to figure out should I get a full frame sensor or this smaller 28 millimeter 1.5 crop sensor? 'Cause this is where a lot of cameras and a lot of lenses are. It's kind of a big tipping point. Do I go smaller or do I go larger? And so I wanted to compare these two at a couple of different ways to give you a different feeling on what you are getting with these two sensors. They go by a bunch of different names. Here are the specifications on how large they are. The larger sensor is more than twice the surface area. So there is a pretty significant step up when it comes to that sensor. And so there is a lot of area to work with. It's not just a tiny bit bigger. It is quite a bit bigger in surface area. And so that's what can have a pretty notable impact going forward in the images that you get from it. We're going to take a look at an example from Sony. And so if you were looking Sony cameras, if you were looking at the crop sensor, you might end up with the Sony A6500. Which currently is their top of the line in the crop sensor cameras. And if you thought well what if I was to go full frame? Probably the next jump you would look at is the Sony A7III which is a fantastic camera that has gotten wonderful reviews. Comparing the price on them you will see that getting to that larger size sensor nearly doubles the price of the camera. But we need to also factor in the price of the lenses as well. What sort of lenses would be appropriate on that type of camera? I'm not trying to get exact same lenses. I'm trying to get lenses that are appropriate for that system. So we have a basic zoom, we have a telephoto zoom. Overall price of $3300 roughly right now the way it is on the market. If you're going to step up to a full frame camera you're going to need some different lenses. And you're going to spend almost twice as much money on your final package. And so yeah the camera is only $900 more but you're spending almost $3000, $2500 more in that case to step up from crop to full frame. Let's look at it from a different point of view. In this case we're gonna look at Canon. And I'm choosing seven degree angle to view at f/2.8. Now that might seem kind of strange. But for anybody who shoots sports photography, you need a narrow angle of use so you can shoot subjects that are far away. And if you have an aperture of 2.8 it's going to allow you to work under low white conditions. And so this is a standard that a lot of photographers would like to have for shooting a lot of team sports, high school sports, college sports, even professional sports. If you were gonna do this with a crop camera, you would probably get the Canon 7D Mark II and you could get a 200 millimeter f/2.8 lens for a total package price of $2100. If you said okay let's step up. Let's compete with the big boys and girls. We're going to buy full frame. What would we get? Well I'm not even go with the top of the line. Let's just come down a step from Canon's top of the line. Go with the 5D Mark IV. But the lens price just shoots through the roof when you shoot with these fast telephotos. And so you are at more than triple the price because lenses get very expensive. And this is why a lot of bird photographers and a lot of sports photographers who are not doing this as their full time career are in to crop frame cameras. Because they are able to get good quality images, great quality images at much lower prices and lower weight levels. Let's compare this once again. This time we'll be looking at a Nikon D750 in the full frame and maybe this is a wedding photographer who wants two fast, professional zoom lenses. They want a normal fast zoom. And a telephoto fast zoom. How much money are they going to spend? And how much weight are they going to carry around? So we're looking at 6400 US dollars. Almost seven pounds. What if they were to step down in sensor size? Well let's just go with a completely different camera here. The Fuji X-T3. A lot of people consider this one of the best crop frame cameras out on the market. And so it's a good camera. It's not the same as the D but kind of similar in some ways. We have two fast zooms that have exactly the same range with exactly the same aperture. So you're going to end up shooting at the same shutter speeds and the same apertures in those same situations. How much does this cost? And how much does it weigh? Okay you'll notice it's notably less in both price and weight. Let's go one step further and go down to 4/3. The OM=D E-M5 II is a very good camera. It's not the same as the X-T3s. It's not the same as the 750. But I wanted to get a comparable camera that fits with those fast lenses. And when we look at the price here it comes down again a little bit in price. And quite a bit in weight. Because of that smaller size sensor, it ables you to get into these smaller lighter weight lenses. And so you need to be thinking about the entire package that you want to end up with and what you are happier carrying around. And the thing that you have to come to grips with is that no matter what you buy, there is always going to be something else better than you had. Now granted you may have to spend two, three, four, 10 times as much to get better. But there's always going to be something better. So you have to draw a limit as to how much do you need. For instance when you buy a car. There's always going to be a car that's a little bit faster than the one you bought. And you have to realize how fast do I need this car to go? And so just be realistic about your needs. Now one of the things about these that I haven't talked real closely about that I want to address is that there is something that you can do more easily with full frame cameras. And you know it probably seems strange to people who aren't in photography. But the out of focus area in a photograph is very important to people who are in to photography. Okay? It's the bokeh. It's the aesthetic quality of the out of focus area. And this is more easily done with larger sensor cameras because of the types of lenses that they have on it. And so if you do a lot of portrait work or you want to isolate your subject while blurring the background, it can be very handy in a lot of very practical areas of photography. So we have our subject in focus. And our background is out of focus. Is this pleasing to your eye or not? This particular image was shot with a micro 4/3 sensor which is the smallest of the groupings that I've been talking about. And then we have it where the background is increasingly more out of focus with the larger frame sensor. So it depends a little bit on which lens you are using as to how much you'll be able to blur the background out. Now I do have an example of all of these lenses right here. So I'm going to grab these. I'm going to see if I can carry them all over at the same time so that you can see what these lenses look like. And so we'll line them up with full frame on the left. The 1.5 crop in the middle. And you know there is a very large lens hood on here so I'm gonna take off the lens hood so that you get a better idea on the actual size of the lens. And it doesn't look totally right because full frame is notably larger than the 1.5 crop. But the 4/3 crop is actually pretty large and I think that's just because they put a lot of glass and they really wanted to make this as great a lens as they could. Granted this Fuji lens is fantastic. But this 42.5 is very good for the micro 4/3 system. So all of these lenses are fantastic portrait lenses. They'll render your background out of focus. The larger you go up in sensor size, the more you will be able to blur that out. I think the throwing the background out of focus might've gotten a little out of hand in the last few years because that's not really how everybody shoots portraits. A lot of times when you're photographing somebody you don't want the nose and the ears out of focus. And a lot of portrait photographers are shooting at f/2.8 or four or five six. And only in some of those cases do you need that lens that goes all the way down to 1.2. So all of these lenses are shooting with the exact same angle of view and they are shooting with the exact same aperture which is 1.2, which is one of the fastest native lenses that you can get. There are some other ways of getting faster lenses and there's an interest in how fast a lens you can get. So there's always going to be some specialty items. But you can shoot shallow depth of field with all the systems. It's just a matter of how extreme do you need to get. All right so summing up on our sensor sizes. Which ones do you want to get? So if you want the absolute best in quality, that is going to be full frame sensors. Best in the light. There's a large system. That's where a lot of photographers are these days. And so it is a pro favorite. And while it is subjective on my part personally so you can disagree with me on this one which is perfectly fine. I think the top good ISO in most of these full frame cameras is around 12,800. If you go over that the noise level becomes really really heavy in that case. Which is extremely low light. I would rarely ever use 12,800. The 1.5 crop is probably a very good value for most people. There's a lot of options out there. I think it's extremely good for sports and wildlife. In many cases I will choose a 1.5 crop when I am shooting sports. And when I am shooting wildlife because it makes the lenses reach a little bit further and allows me to do more work out there in some ways with that. Because of the smaller size sensor the ISO is not as good. So it's not as good under low light conditions. So I think the top good ISO on most of those cameras is around 6400. So you come down a step in the size of the sensor, you come down a step in how hard and how far you can push the ISO. 4/3, it's going to be the most compact and lightest weight system. So if weight is a key issue, you're a light weight backpacker and you really want to have a lightweight system out there, 4/3 is probably what I would look at. Once again a step smaller in size means that the sensor is going to be about a stop less in image quality when you start pushing it. Now if you're familiar with ISOs, you'll know that shooting at ISO 3200, 6400, and 12, are some pretty low light conditions. And so you'll have to be an honest judge for yourself as to how low of light are you shooting in? If you're doing concert photography with low light to almost no light, then you want the largest size sensor possible. If you're out shooting your kids' soccer game on Saturday afternoons you're probably going to be fine with any one of these choices 'cause there's more than enough light to work with. And so something else to consider when trying to figure out what is the right camera for you.

Class Description

Our Camera Buyer's guide will be your guide to figuring out the best digital camera for your needs.

Gear expert John Greengo dives into the major brands and lenses that are currently on the market.

John breaks down some of the more confusing aspects of mirrorless and DSLR's from focusing systems to sensor size; you'll get a better understanding of what the gear does so you can make an informed decision.

At the end of the class, John gives his recommendations for different types of photographers from the aspiring student to the filmmaker and everyone in between. If you're looking to purchase a camera or gift one to a budding photographer in your life- this free course will be your guide in making the best purchase.

Class Materials

Free Bonus Material

Camera Buyer's Guide Download

Ratings and Reviews

Student Work

Related Classes


Denise Watson

Another outstanding class by John Greengo, my favorite Creative Live instructor. John's delivery is entertaining and his info clear and very easy to understand. If you need more explanation, well, don't worry - he's got a slide or PDF for that! I'm a working photographer and I learn something new with each of John's classes. Don't hesitate to buy any of his classes - you won't regret it.

David Reichel

Yes - there is such a thing as a free lunch - this class is it! I enjoy landscape, seascape, architecture, portrait and travel photography. I've been a Canon user for decades (film and then digital full frame with the 5D Mark II then 5D Mark IV). Recently I got a Fujifilm mirrorless medium format GFX 50R and discovered some Fujifilm features (e.g., film simulation, menu system) that resonate with me. I now have over-kill on full frame format and because I like the Fujifilm so much, I've been thinking about moving from my Canon 5D Mark IV to a Fujifilm X-T3 as my walk-around camera. This class helped me better understand the trade-offs and alleviated my concerns about a crop format sensor in the X-T3. On top of that, this is a great refresher course on camera fundamentals.

Sherry Throughmyeyes Prater

There a thousands of reviews/guides/ floating around the internet, but this one is by far the best by far. I usually watch a portion and then move on because I simply lose interest, but I watched every single lesson. John gives a very unbiased explanation of cameras, functions for every type of shooter. Not only would I recommend it, but I am going to recommend. I am a member of multiple photography groups on FB and one of the most asked questions is camera buying advice. This is excellent!