Digital Camera Picture Quality
Mark Comon (Vice President, Paul's Photo, Torrance, CA) gives expert video advice on: Can a digital camera capture high-quality video?; Can a cell phone capture high-quality stills?; Can a video camcorder capture high-quality digital stills? and more...
What determines the quality of a digital photo?
What makes a great digital picture? First of all, it's photographer skill. You've got to know how to hold and point and capture the subject with the camera. That's number one. Number two, you need a lens quality. Lens quality is far more important than any other aspect in digital photography. And if you look, I can show you examples from three and four and five megapixel digital cameras with premium, excellent quality lenses that blow the doors right off the ten and eight megapixel cameras with lower quality lenses. So look for lens quality. Number two, you do need megapixels to be able to make enlargements. But megapixels only gives you picture size. That's all it does. Chip size is also huge. The bigger the imaging chip in the camera, the better the prints are going to be. That's why the SLR cameras take much better pictures than the compacts, because the imaging chip on the SLR is a little bit larger than a postage stamp, while the imaging chip on your compact cameras is a little bit bigger than the nail on my pinky.
What is the "lens"?
With digital camera picture quality, the camera lens is probably the most important single part or component of a camera that you own. Most people think a lot of times about buying a camera and then decide heavily on which camera they want. They look at the features and then they buy whatever lens is on sale, and I think that's a mistake, because the lens is clearly the most important part of a camera. It's the eyes to the camera. If you think about yourself and how you would react to the world with bad eyes versus good eyes; the lens is the eyes, and the better the eyes, the better the picture that you're going to take. The lens of a camera work just as our eyes do, there's a glass lens that focuses the light, the better the lens focuses the light, the clearer the picture you will have. It focuses the light of course to the imaging chip you have in your digital camera; otherwise it focuses on the film in a film camera.
What is "resolution" and how does it affect digital photo image quality?
With digital camera picture quality, when you buy a digital camera you have to choose the number of megapixels. The megapixels is the size of the imaging chip, some people call that the resolution. What you need to know about megapixels is this, to make a 4x6 size print of photo quality you need 1 megapixel, to make a 5x7 print you need 2 megapixels, to make an 8x1 print you need 4 megapixels and that will give you true photo quality. So, when you're buying a digital camera what you get when you buy more megapixels is the ability to make larger enlargements and the ability to crop the picture, it's just that simple. Once again though, remember that lens quality is far more important to your overall picture quality than how many megapixels you have, as long as you make sure you are in the range of what you can do with your digital camera.
What is a digital camera's "megapixel"?
With regards to megapixels in digital camera picture quality, "Mega" means "million" and "Pixel" means "picture element". So, when you buy the megapixels on your digital camera, it is how many million picture elements or dots it can take. If you take a look at the newspaper with a magnifying glass, or go right up next to the TV, you'll see that the pictures are made up of individual little dots, these are pixels. Therefore if you have a six megapixel digital camera, it means that the image is roughly 3 pixels wide and 2 pixels high, because 3 times 2 is 6, hence six megapixels.
How many megapixels should my digital camera have?
Now, you need four megapixels to make an eight-by-ten print. If I'm never going to make anything more than an eight-by-ten, why do I need anything more than four? Well, the reason is, the last time I took a perfect picture was: never. so, if I have a six-megapixel camera, that means I can crop my file image after I've taken it, and throw away a third of it. If I have an eight-megapixel camera, I can throw away half of it – and still have four megapixels that will give me an eight-by-ten quality when I make my enlargement, when I make the print for the wall. If I have a twelve-megapixel camera, I can throw away two-thirds of it. That's why you spend the money for more megapixels – it doesn't give you a clearer picture, it gives you the ability to crop and adjust the picture later on.
What is "ISO speed" and how does it affect my digital camera's photos?
It's just like the ISO speed was on your film. ISO tells us what sensitivity or how much light is required to make the picture. Now on film, ISO, higher ISO, gave us a grainier less clear picture; a lower ISO gave us better color and better clarity. The same happens in digital. As you turn down the ISO you're going to get clearer, crisper, better colored pictures. As you turn up the ISO, it needs less light to take the picture, but we get digital noise, looks like kinda snow on the TV set, you get these kinda colored artifacts, kinda freaky-deaky in the picture, thats what grain or noise is on your digital picture. My recommendation to you is: always set the digital camera to the lowest or next to the lowest for general purpose photography. If you shoot inside without a flash, indoors, you know, like a basketball game, hockey game, you know, indoor play or something like that, then you need to boost the ISO. But one thing I need to tell you is before you do that is you have to take a test on your camera because some cameras have a very low threshold for noise or the picture quality gets pretty bad, pretty quickly. So, you have to test with your individual cameras. You need to also note that the smaller cameras, the compacts, give more noise then the SLRs do, and that goes back again to the size of the imaging chip with a small imaging chip we get more noise or more grain, With the SLRs and the bigger imaging chip we get less noise and therefore we're able to boost the ISO higher and give you more low-light capability.
What ISO speed range should my digital camera have?
In general, for normal photography you need an ISO range of between 2 and 8 for general purpose photography. 2 for bright sunshine, outdoors and normal things. 4 for mixed light and low light family pictures. 8 for the occasional show, play or children's performance. You need higher ISOs for more specific low light kind of photography. If you are doing a lot of that kind of thing, you've got children in drama productions and playing indoor sports you may want something that goes to 16 or 32. If you are doing a lot of high quality, high colored landscape, tripod type of photography, you may want a camera that goes down in to the 5 to 1 range, but, those are more specific. So, in general, 2 to 8 is where you need to focus. All the digital cameras today have that.
Can a digital camera capture high-quality video?
With digital camera picture quality, most of your compact digital cameras today, still cameras are able to catch high-quality video as they do have a movie mode. This is ideal and cool for taking the occasional movie. Once again, just like the movie cameras don't do as well for still cameras, the still cameras do not do as well for movies, but do great still pictures. For someone's first steps or something unexpected, it's great to have the movie function with a compact still camera.
Can a cell phone capture high-quality stills?
Whenever I go anywhere, I see all kinds of people taking pictures with their cell phones. I just really question the quality of the pictures they're going to get. Because, even though the cell phones today have three, four or five megapixels, the quality of the lens and the size of the imaging chip is miniscule. I know it's very tempting and sexy to think that your cell phone can be everything to you, whether it's still or moving. Look at the movies you get off the cell phone. Have you ever printed a picture from a cell phone? Look at how low the quality is. I personally want more from my camera than what I'm going to get from a cell phone.
Can a video camcorder capture high-quality digital stills?
Today's digital video camcorders more often than not have a high-quality digital still capability. That is really good for capturing an occasional still picture. But digital video camcorders don't take as good a picture as still cameras for a couple of reasons. Number one, the lens quality; the lens quality on the camcorders is not as good as the lens quality on the still cameras. Number two, the imaging chip is still even smaller and they're designed for moving pictures. With moving pictures the human eye does not need to see resolution. The human eye builds in the resolution for you. With a still camera, we examine, we get in there and look for the fine details, so you need more detail with a still camera than you do with a camcorder. Maybe one day they'll be able to combine them both so that you get both in one, but not yet, we're not there yet.