What the big deal with megapixels?

Thank you? So today we were going to talk about digital cameras and specifically megapixels, right, and uh, here's something this is probably that we should call us like the podcast they don't want you to listen to. They being, you know, the digital camera manufacturers and shops, because megapixels.

That's one of those things that that a lot of manufacturers used to kind of differentiate their product from other other competitors, like you know, this camera has ten megapixels, or you'll see that in a lot of smartphones or cell phones even now, where you'll say, like this cell phone has three mega pixels, and there's a lot of confusion like what does that mean? Are the higher numbers automatically better? Um? Is there a point where the numbers

don't really matter anymore? So we're kinda gonna talk about that and sort of straighten these things out. Yeah, and and and to be honest, they probably wouldn't even care if you didn't know the truth. They just uh, you know, it's a number that gets that people attached themselves too, because they can they cann sort of compare it to other machines. I mean it's sort of like, uh, mega hurts, the mega hurts myth as they used to call it for computer chips, because you'd say, oh, well that's faster,

that means it's better. Well, you know, megapixels is the same way. Just because there are more megapixels in a camera's ability to shoot. Um, yeah, it doesn't necessarily make it a better camera. It just means it can capture an image of more area. Right. It doesn't mean that the pictures themselves will come out any clearer or sharper. Um. It's just that alone anyway, right right. I mean the megapixels do play a part in that. But here's the thing.

A lot of people have chosen the megapixel number as the way to define a digital camera. Right. It's like because it's easy. Yeah, It's like that's an easy number. You look at you're like, oh, well, this is a five megapixel camera. This is a seven megapixel camera. Therefore the seven one is better. That's not necessarily the case. It may turn out that you could use both of those cameras in similar lighting conditions to take a photo, and the five megapixel camera may end up giving you

a better picture. Because it's not all about megapixels. It's a lot about the lens of the camera, the sensor in the camera, the the software in the camera. All of these things play a major factor in how a picture looks once you've taken the photos. So just because a camera has the capacity to take more or to cram more pixels into a picture, doesn't mean that that picture is going to be better necessarily, that's true. Um. There was a semi famous experiment that David Pogue did

from the New York Times. He uh, he was on a Discovery Channel show called It's All Geek to Me, And basically they took three pictures, one that had been taken with a thirteen megapixel camera, another with an eight, and another with a five. Basically made all three pictures sixteen by twenty four and um, only one person that they showed, you know, they went out in public, and only one person that they showed could accurately figure out which one was which, and that might have even been

a guess. Yes, but I should point out, Um, there's one minor correction I need to make here. Okay, he did not use three different cameras. He used one camera and then used Adobe Photoshop to pull out mega to pull out pixels to give you the equivalent of a thirteen megapixel versus a seven versus a five. And his logic was that it doesn't really matter if you're taking pixels away or if you're using three different cameras that

capture three different uh amounts of megapixels. Um, it doesn't that that's immaterial because you end up with the same thing. It's the number of pixels in the image. Other people were saying, no, no, no, because you're using Adobe and you're artificially removing these pixels. That's what's affecting the image. By this point was that it doesn't affect the image.

You could you know, they all looked pretty much identical to one another, and as Chris pointed out, only one person noticed any difference at all, and even that might have been a guess. But here's here's why he did

not pick three different cameras. There was actually a good reason for it, and that's the reason I was mentioning before that things like the camera's lens and sensors can make a huge difference in what how a picture looks when it comes out, and there's no way of guaranteeing that three different cameras are gonna give you the same sort of image just because you know they're using different lenses,

they have different sensors, they have different software. So after hearing this objection, what happened was he actually got a photographer, a professional photographer wrote in and said, hey, I've got a way that might fix this problem where we can test this without you having to take megapixels out or any pixels out. I shouldn't use the word megapixels um

any pixels out. So what he did was he brought a camera I think it was a sixteen point seven megapixel professional camera, and then took the same picture three times from three different distances. Because the idea being that, uh, you know, essentially you crop out everything that's unnecessary in the larger picture and zoom in and you get the same effect as you would if you had a picture

using fewer pixels. For that same general area. So it's kind of you know, cutting away all the stuff you don't need in order to look at the stuff that you can compare you know, apples to apples. And once again, no one could really tell the difference. I think three people out of fifty we're able to correctly identify the three different images, but that means forty seven people couldn't. Yeah, yeah, well, um,

you know that's true. A lot of people did object to the methodology, uh, that that David Pogue used, and George Woo from zd net actually wrote a pretty substantive blog post in which he basically went through all the things that that uh, you know, David poke hadn't really taken into account, including down sampling, UM, you know, things like optical resolution test, which would give you a better

idea of the actual camera resolution. UM basically said, you can't just look, you know, take a picture of a random thing and compared to another picture of the same thing and say that's got better resolution. You need to actually use, um a card, an optical resolution card, and

and you know examine how the camera can can use that. Um. They use JPEGs, which is a lossy compression for mhat loses information when you save it, rather than that um who said that he should have used um tiff or the raw camera format, um, you know, and basically anything motion wise. UM yeah, I should have seen the flaw in my argument of about the three different cameras. Any motion at all, um, you know would affect the picture because it would show the limitations of the lens and

the shutter speed. So I mean there were a lot of things that you know, in the in the the process of putting together the three images, um, you know, could have been done differently to show the difference in the three different resolutions or I should say areas, because megapixels are actually area. Yeah, we should probably go into that a little bit. So you think, all right, I've got three megapixel camera, what does that mean? Okay? So

images digital images are made up of pixels. That's picture elements. It's little dots of light. And Uh, the way you figure out the megapixels is you multiply the number of pixels that go horizontally across an image and the number of pixels that go vertically across the image. Multiply those two numbers together, and the amount you get kind of gives you the idea of a how many megapixels that

camera has. So for an example, let's say you've got two thousand, forty eight pixels horizontally, uh, and you've got one thirty six pixels vertically, and multiply those two together you get a little over three million pixels. That's a three megapixel camera. So if you're talking about a ten megapixel camera, you have far more pixels horizontally and vertically, actually not far more, but more. Um when you when you start looking at it that way, with the area,

the increase is really not that significant. It sounds like it is, but when you think of how many are going horizontally versus vertically, it really isn't that significant. The only time it really comes into places when you're printing out enormous pictures. You know, um, if you're using anything like a four megapixel camera or around that area like a six by eight photos should be fine. Um. It's only when you start to say, hey, I want to cover this wall in a digital photo, know that you

have to start thinking, all right, I need enough. I need to I need to have a camera with enough megapixels so that it's not gonna look blocky when I printed out, but most of us, you know, for most

of us, I don't think that's an issue. I mean, I mean, if you're gonna shoot a three by five or four by six or even you know, eight and a half by eleven sized, you know, that's not like a five megapixel camera is good for pretty much anything up to poster size really, uh and and very few of us, at least on the amateur side of photography,

are going to print anything larger than that. Um. It's really when you're getting into the semi professional or professional where you'd have to worry about something where you need more pixels in your in your digital image. So the question then, is what's the most important thing for you to look for in a camera. If it's not megapixels, this is tricky. Yeah, here, this is this is not an easy question to answer. There's no easy answer. Unfortunately. It's not like we can tell you, oh, well, look

for this lens or look for this particular kind of sensor. Um. It really depends on how the manufacturer put the cameras together. And you may very well come up with a five megapixel camera and compared against a twelve megapixel camera and see that your pictures in the five one are are far better. But a lot of that depends on your skill as a photographer. The lighting, the composition of the shot, um, whether or not your your subject is moving, uh, you know,

and and the software that the cameras running on. I mean, all of that stuff plays a factor. So the best thing to do is probably test as many cameras as you possibly can before making a purchase. It would also probably help if you read uh professional reviews. Um. You know, people who do photography all the time are you know, certainly going to be more knowledgeable since they you know, that's what they do. Um, so they're going to have the experience that will help you, you know, figure this out.

And there are many professional photography Matt magazines out there that that can help. And I'm sure that you know, would probably be in your interest to visit a professional camera store. You know, they they'd be happy to sell you have five megapixel camera, just as happy as they would be too, you know on Modus sixteen point seven megapixel camera. I didn't even know they made those. Well that's for professionals. Yeah yeah, no you guys, yeah, yeah, no,

you can you can find them. I mean they're really expensive because it relates for the professional who can afford to purchase it because it's part of a business. But um, yeah I have I have a ten megapixel camera and uh I got it because it was on sale and it takes great pictures. But you know what, I also have an older for megapixel camera that also takes great pictures. It's not as a sleek It's doesn't have all the features that my other camera has, so I don't use

it very often. But it the fact remains that for my purposes, I could have stuck with the old camera if I really wanted to. It's just that it's bulkier, uh, and it doesn't have some of the neat features, like some of the nice like nighttime shoot features things like that. Um. You should also remember that if you have a camera that has a lot of like goes on the high megapixel side, some people have found that shooting and low lighting UH tends to you tend to get these little

light specs um that sometimes pop up. That's not with every brand of camera, but it can happen. So again, don't just rush out and buy like the newest camera. Because they've talked about how many megapixels, it has really look into the other factors. Uh, you know, cost is definitely something you should look at. Reliability, battery life, I mean, all of these things are important as well as of course the quality of the pictures sure, and um, you know,

an image sensor, quality of the lens. You know, these are things that that you really should take a look at it. And it's you know, unfortunately, it's not gonna be something you can figure out in five minutes. Probably they might take a little research and and if it's gonna be something that you're gonna invest a couple hundred dollars in or more more, then you should. You know, you should really take the time to to look into it anyway. Um, besides, you don't really need all those

extra megapixels anyway. I mean, you know, Mike Elgin from Computer World was saying that if you're taking pictures with you know, tons and tons of information, as you know, these double digit megapixel cameras have, then you've got to

find a place to store all these things. And they slow down your camera, so you know, I can think of, yeah, exactly, do your camera it's slowly and the transfers really slow, like if you've got a lot of of pictures that you've taken with a ten megapixel camera, and you've taken them on the highest setting. It takes a while to pull those off, to rip those off of a smart card. But I can think of one other instance where you

might want a camera that has a lot of megapixels. Okay, let's say that you're taking a picture of a big group of people and you're looking at the picture later and you're like, Wow, that chick is cute. I really want to have a full size picture of that chick. But you know what, I don't want a restraining order. So what I'm gonna do is I'm going to crop everyone else out, and I'm gonna expand this picture so

that she takes up a full frame. Then you might need a lot of megapixels so that when you do crop everyone out and expand that section, there's enough resolution there so that you can still tell that that's a human being. I'm going to avoid asking you whether you know this from experience. I will neither confirm nor deny that. Okay, then Alice and Anakin call me, so all right, Well that's got it for myne Okay, excellent, Well, then you

know what I think. I think I've pretty much covered it too, so um, you know that brings us around to well, you know what time it is? Right, Yes, it's listener me. Seriously, I need to bring earplugs for that. Yeah, I know. Okay, So today's listener mail comes from Michelle Bell Me sham mom soon, I know. I'm sorry. Michelle says, I can't remember if this should go to how Stuff Works or tech Stuff Podcast, so I'll send it to

the generic address it got to us, so congrats. I think it was Chris and Jonathan who were talking about fun three D technology and how it works. A comment was made that the color spectrum three D glasses and technology wasn't something that really took off because the massive headaches and ice strain that were fairly common, and someone had wondered about the polarization three D glasses and tech

and if it worked any better. I just finished watching Coraline, awesome movie even if you haven't read the book, and yes, it's a good movie for grown ups too, and my husband and I were in a showing that was showing with polarized three D. It was amazing and I used the glasses through the whole movie. I'm happy to report no headaches or ice strain, and it was very much worth the experience, thank of Michelle. Um. I actually also saw Coraline in three D, and I with the polarized glasses,

I can also report no headaches. My wife's saying it was a great experience. Uh, I think we're in for a nice long future of three D films. It may not be, it may not dominate the industry, but I think I think it's more than a novelty. We'll see. Well, it's good that it didn't leave you flat right. It was a deep, deep film. So if any of you have any comments, questions, suggestions, corrections, anything like that, you can write to us at tech stuff at how stuff

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