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Lesson 6 from: How to Choose Your First DSLR Camera

John Greengo

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Lesson Info

6. Pixels

Lesson Info


One of the most confusing aspects for people is how many pixels or mega pickles or what it was, what is it that I need in that camera? And so let's talk about pixels, what they are and how many u need for what you're going to be doing in photography? So pixels is, of course, the word that has been derived from picture element that's, the light sensitive cell that is capturing the light in the sensor. Now very common camera these days is going to have six thousand columns and four thousand rows of pixels, and if you remember six thousand times four thousand that's twenty four million, or what we call twenty four megapixels in the camera, so you'll often see cameras with a twenty four mp as the rating of how much summer, how many pixels they have in them. And so we're going to put this scale over here on the right hand side from zero up to fifty, which is where the top of the line camera is right now and let's, talk a little bit about how many pixels you need and what we're going to star...

t off with is talking about dp I dots parents, and this is important when it comes to computer monitors or when you're printing an image, how many dots per inch do you need to make a nice, clear image? So one dot two dots well, that's, more detailed. We want more dots per inch if you have ten dots. Well, you can still clearly discern that those air dots and not a continuous line we get up to fifty dots per inch. Ok, well, we can still see that's not quite a smooth line. Now, the limit of human vision in most people in most cases is going to be about three hundred dots per inch, so if you wanted to have six hundred or thousand or million dots per inch, it just doesn't do much good because our eyes can't see that different distance. And so three hundred d p I is really a pretty good standard if you want to print something out and you wanted super high quality so that anyone looking at it won't be able to discern the individual dots because they're too small to see for the I would have to go to around three hundred d p I and some of you have probably heard about apple's retina displays, and this is part of the technology that they're using is just a lot of dots per inch to achieve something that just looks realistic. It doesn't look like dots anymore now, having said this, there's some variables in here because some of us can focus up closer than other people. So if you were to hand up, say, two hundred eighty dots parents to somebody who could focus very closely, they might be able to discern those dots, and also we have different quality of vision some people can just see more sharply than others, but one of the most important things to think about when it comes to pixels in your final image is the viewing distance. How close is that subject to your eyes when you're looking at it? When you hold up a four by six photo that's going to be probably about as close as you can get it to your eyes so that you can see how sharp in detail that isthe when you're looking at a computer monitor that's going to be a little bit further away, and when you print out a photo to hang up on the wall, you're going to stand further from it. Now. How detailed does your print on the wall need to be? It depends on how close you're going to stand next to it, so normal printing is going to be at three hundred dots bridge because people hold that up really close? Does anyone have an idea at what billboards are printed at in dots per inch? Would you believe that they're printed it only nine dots per inch? Because they know no one is going to go up close to it? And so if you're going to print a picture and you going to put it up on the wall and you know that you're not going to go up real close to it, you could print it at two hundred dots per inch that's not a problem now there are some people and they just can't help themselves they got to go stand up right next to the print and look at it as closely as they can to see how detailed it is and this is what we call a pixel paper they're trying to peep at those pixels to see how sharp is this and it's nice to have an image that's that sharp but it's not really necessary for the way most of us enjoy a photograph and so getting back to that question how many pixels do you need and the answer is is it depends on your output? It depends on what you're going to do with the photograph and the two factors you need to think about is what size is the picture and what's the viewing distance of the picture so let's go for some real world examples. All right you're going toe post a picture on the internet you're going to send a picture of a facebook or something like that you don't need very much you need a little tiny picture that's about six hundred by four hundred pixels and size, which is point two four megapixels now the camera we were talking about a few slides ago was twenty four megapixels, which is one hundred times more than this and so this is super easy to dio. Now let's say you have somebody who has a very fancy laptop computer with extremely high resolution on it and you want to send him a file that they can open up and look at their entire laptop screen and it fills the frame that's about eight megapixels the latest generation of monitors for home computers are what are known as five k monitors. They have five thousand pixels across the long side of it, which would mean you would need fifteen mega pixels to fill that up entirely. So if you said this is how I mainly use my pictures, you would need a fifteen mega pixel camera or more but fifteen would do the job now another way that we can use our cameras is for putting them onto tv so standard tvs which still many people around the world have but many of us have upgraded to the hd tvs use extremely small resolutions. The standard right now around most of the world is an hd tv nineteen twenty by ten eighty and pixel resolution, which is two point five megapixels very, very easy to do with modern cameras the next generation of tv, the tvs that are right now in there they're down at the tv shops there those one special ones off in the corner there might be two of them there they sell for two three four five thousand dollars and you can walk right up to the screens and go wow look how sharp it is and they're pretty amazing tvs and they're probably what we're going to be buying in five to ten years and I'll be honest with you I'm not really excited about him they're better but I know in my house when I sit down to watch tv I'm about twelve feet away from the tv and in order for me to see this distance I have to walk up really close to the tv to see that it's a eight k or in this case of four k tv and if you're not viewing your tv really close up it doesn't make any difference and so there's going to be a point of diminishing returns we're adding more pixels to our tvs just doesn't help because there are already people talking about eight k which is eight thousand pixels approximately on the long side and so long term thirty years down the road we're going to be watching eight k tvs which you would need thirty nine mega pixels to really fill that frame but you would also have to be a really close with which would be kind of uncomfortable watching a large tv monitor so when it gets down to this if you want to put your cameras on the tv right now all you need is more than ten megapixels the way that I'm figuring out these numbers is that there's a slightly different shape in cameras versus tvs and I wanted to make sure that we were filling the frame in order to get the size is correct. One of the other ways of utilizing your pictures is by printing them so let's say you want to make a small four by six inch print you only need two megapixels in order to do that very easy to do let's say you wanted a medium size print that could be put saying a large book you've seen those nice big coffee table books suppose you wantto print that goes in there that looks really good you get maybe a copy of national geographic magazine you see it a beautiful photo I would like to take a photo of that quality you're going to need a camera that she was somewhere between six and nine megapixels. Now the reason I have some different numbers in here between six and nine is I put one at three hundred d p I which is kind of the highest standard that most people print by and two forty which is where a lot of people print out in order to get a slightly larger size and it compromises the quality ever so slightly but there's a lot of people who printed two hundred twenty dots per inch or two hundred or even one hundred eighty dot's bridge in order to get an even larger size. Now if you want to get something bigger than this and well I guess I should mention first that most cameras that we're gonna be talking about on the market today are between twelve and twenty four megapixels so there's more than enough for making small and medium sized prints and doing everything on screen if you want to make a poster size enlargement two foot by three foot in size that's where you're going to need massive numbers of pixels now I know that there are many photographers who will make a thirty six by twenty four inch print and they will do it from a twelve megapixel camera and because it's a good photograph they used to good lands that good lighting good composition and everything else was working for him they were able to make a thirty six inch by twenty four inch print from a twelve megapixel camera by just up president and using a little bit of computer software in order to do this so ideally you would want to have fifty to seventy five megapixels but it can be done with far less than that and so what is the biggest picture that you think that you will ever print and that is something to think about when trying to figure out how many megapixels you need now I do have to admit there is an x factor in all this and that is these photos that you take today maybe with you or your family or your friends for decades to come and it's always going to be nice to have more resolution and so if I can choose a twenty four megapixel camera over a twenty and everything else is equal I would go for it but everything is not equal and so there's a balance that we need to have for most people if you have a twenty four megapixel sensor you're going to be able to make ahh beautiful seventeen inch by twenty five inch print for your home that's a nice big print to put in your house if you have a twelve megapixel it's going to be a little bit smaller it's going to be around eleven by eighteen which is still a really nice photo and so if you wanted to decorate your home with your own photographs you could do that with a twelve megapixel camera and most of the ones we're talking about here are twenty four and so when it comes to mega pixels I guess what I would like to say more than anything else is get over it it's not that big a deal most of the cameras are grouped fairly close together the difference between sixteen and eighteen is completely insignificant the difference between twenty and twenty four is minuscule. It hardly makes any difference at all. I want to share with you some of the most popular sought after talked about lusted after cameras on the market. All right, the sony a seven r is a thirty six megapixel camera. It's, one of the it is the highest megapixel camera from sony out on the market right now sells for about two grand the nikon d eight ten another favorite choice of a lot of landscape architectural photographers, product photographers, people wanting very high resolution. It is nigh cons highest resolution camera that's three thousand dollars cannon just introduced the new five d s, which is at fifty megapixels. So this is the top in yes, there are a couple of cameras that do go beyond this, but they go into different realms of photography that we're not even going to touch. This is still almost a four thousand dollars camera for somebody who wants the ultimate in detail. All right. So now, while these cameras are very, very popular, let me share with you three more cameras that are also highly sought after. And this might seem a little bit strange when you start looking at the stats. Sony makes a companion camera called the sony a seven s, which is a sibling camera has a lot of the same features but they put a different sensor in there. What they did is they used a twelve megapixel sensor and this camera actually sells for more money and this is a special camera that is very good under low light conditions we're going to talk more about this going forward here ny khan's top of the line camera sells for twice the price of the nikon d a ten has one third the pixels with cannon it's kind of the same story same six thousand dollars price tag but on ly eighteen megapixels these cannon one d exes and nikon d for us is these are the picks for a lot of the photojournalists in sports photographers. Part of the advantage here is that they work under low light conditions really well and they shoot really quickly now also kind of a separate aside there also built a little bit differently in a little bit more rugged but these are the premier cameras down here between twelve and eighteen mega pixels that's where their sweet spot is for the types of uses because what happens when a sports photographer takes their picture? What where does it go? It goes on to the website it might go into into sports illustrated magazine or something like that it's not getting printed in posters in general and so what's better mohr less well that's so that's a really good question, maura less all right, so I'm going to give you an analogy here imagine that it's your turn to buy donuts for the office. Okay, you got a dozen people in the office, so you go to the donut store and you buy yourself a dozen donuts and right is they're ringing you up, they say, did you know that we have a special today and you can get twenty four donuts for the same price is twelve and you think, well, obviously that's a great deal give me the twenty four donuts and they pull out the same size box and immediately you notice you wait a minute, these donuts are smaller than the other donuts and they say, well, we only have one size box if you want more doughnuts, we've got to make them smaller donors because these air these air premium, don't you don't stack these donuts, you don't put him on in, they have their its own cubicle, okay? And so you're thinking, well, should I get twelve big donuts or twenty four small donations? And then you think about your company? Has a policy instituted this policy after last halloween's incident that will remain anonymous, but the company policy states that employees may only take one donut and so if you bring the box of twenty four and you know that everyone's going to get a smaller donut and they're gonna have to throw away all those extra donuts, they're not going to serve you any purpose at all. So in that case, if you on ly need twelve, you go with the twelve and this is kind of that quandary between what's more important size or quantity because when they sell cameras, they on lee talk about quantity, they don't talk about size and it's very easy to kind of manipulate the math with twenty megapixels in twenty four, and this is true whether you're talking about doughnuts or pixels, whether it's twelve pixels or twenty four pixels or as we like to talk about twelve megapixels and twenty four megapixels what's basically true on both donuts and pixels, mohr is better on lee if you need them and so you on ly want as many pixels as you need, so if you know that you don't need any more than sixteen mega pixels that's probably the right camera for you to get because all those extra pixels you're going to end up throwing them away and big pixels haven't advantage big pixels are like solar arrays collecting more light so it's very interesting to use sony as an example because they have three sibling cameras that are all very similar in size, shape menu functions and features, but they put on different sensors on each of their three cameras twelve, twenty four and thirty six megapixels. And so when you have more pixels in the same size sensor, they have to be smaller in size, just like the donuts that we talked about. If you have fewer pixels, they can be bigger in size. The bigger the pixel, the better it is at recording low light, and so if you shoot in a lot of low light situations, you want the biggest pixels, and this is something that is not advertised. When they advertise a camera, they you're going, you're going to be hard pressed to find the size of that pixel somebody's got it out on the internet somewhere, but it's not something that they advertise. They talk about quantity because that's an easy number that people can understand and that's what sells cameras. So I decided to run all three of these cameras through a test, shooting a little test object at different esos, and I'll be honest with you at the small size were looking at here on an hd tv it's not going to be easy to see the difference, and so I'm zoomed in a little bit on the left and a whole lot over on the right, and you can see that with the thirty six megapixel camera on the top the picture on the top right is more detailed than the picture in the bottom right and that's because we have three times as many pixels showing that information but as I get to higher and higher esos you'll notice that the image quality degrades mohr over with the thirty six megapixel picture and you'll notice it's really quite a bit here where the twenty four and the thirty six have really started to go a little bit walking in their color and their descriptions of the blacks in here and the twelve megapixel here it is so twenty five thousand which is a very high I s so it's done much better under low light conditions and so this is where you really have to be honest about how you are using the camera in good light versus low light situations and how many pixels you need because in a relatively small usage like this which for us is just on a computer screen or on a tv screen it's hard to tell the difference between twelve megapixels and thirty six even when we're shooting twelve megapixels at twenty five thousand sl and so in this whole debate when it comes down to pixels do I want more pixels or do I want less pixels? What are some things to consider when you're comparing the amount of pixels so more pixels is obviously greater resolution which means that you can make bigger enlargement, bigger prints from that that's important to you? You look for those higher resolution cameras, it does give you more ability to crop in and use a smaller selection later on. Now, this is something that we don't like to talk about and you're not supposed to crop in you're supposed to shoot it as you wanted, we all end up cropping in and it's always nice to have more resolution to crop in and so that's always a hand the advantage, of course, we like that the greater kind camera life span what I'm referring to there is cameras do have a life span, as I said, you know, three to five years that you're probably going to keep it with you, and then they're going to come out with new cameras higher resolution that have better processing that are better at low light conditions and you're going to want upgrade. But this having a camera with more resolution means that you're probably get a little bit more life out of that particular camera. Less pixels means you're going to be able to do better under low light conditions because you have fewer pixels. The file size is going to be smaller and your cameras going to be able to process that in that information faster and it's going to be able to shoot faster, so if you shoot sports photography you want less pixels because the camera is faster at processing that information you khun storm or images on a card and you could transfer faster from camera to camera. So for instance, let's see over here on the cameras. Where is it may be down here. So the cannon seven d has twenty megapixel, which is fairly moderate these days, but because it has twenty and not twenty four or thirty six, it can shoot it ten frames per second, which makes it a really good sports camera. It's not as good a resolution is this camera here, which uses a full frame sensor in twenty two megapixels. And one of the things that has really happened with cameras more and more over the last year last few years is they've really become compartmentalized. They've specialists in certain things, this camera is really good at this. This camera is really good at that. And so it's not which cameras better it's just what is it exactly good, for in some ways, the analogy that I like to use is going to the shoe store. Would you ever walk into a shoe store and say, hey, bring out the best parachutes you got? Well, you going out to dinner or you working in the yard? You're going to run a marathon or you playing basketball and what size of foot do you have, by the way? Because if they just bring out a random parrish shoes, the most expensive pair of shoes, it could be totally wrong for what you're doing. And so figuring out the pixels is one of most important things in that regards.

Class Materials

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John Greengo - How To Choose Your First DSLR - Reference Guide.pdf

Ratings and Reviews


I have to thank John Greengo and the CreativeLive staff for another wonderful class. Mr. Greengo is a very good instructor (he has a nice Bob Ross ambiance), very knowledgeable and very technical with the camera and the terminologies. I am very grateful that he has material to download so I can continue to review and learn. I own a DSLR but I never truly understood the baseline technology. I am in the process of purchasing a new camera system and lens for some photography but mostly for filmmaking. With the knowledge I gain by watching this course, I can better choose and identify the features of the future cameras in my upcoming new passion. Thank you CreativeLive and Thank you Mr. Greengo. I am looking forward to attending future classes.


This was a great class. I already had an idea of the direction I wanted to go as I start my new business, but this class really helped me focus on the most important upgrades I need to make to my current system. I was particularly impressed with the visual graphics used to explain the technical functions of cameras and how those functions affect image quality and camera use. I would highly recommend this class to anyone who wants to up their camera system and I am looking forward to taking the classes that are specific to the camera systems I am using. I would love to see a class on image processing and getting the most out of editing software. Great Job! Glad I signed up for CreativeLive.

Bev Anne

Excellent course. I was happy to find out that I made a good choice when purchasing my entry level DSLR camera -- it does everything I need at the moment. I was also interested to find out that mirrorless is the wave of the future -- I really like the idea of the light weight because I am developing some arthritis in my wrists and when I am ready to move up in the future I will have great options. Meanwhile I also learned that there is an inexpensive lens that I can get that will upgrade my system enough for the immediate future. Thank you John Greengo for this informative class it was well worth the purchase price.

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