Digital Cameras -- How much does the Pixilation REALLY matter?

Question

I will be purchasing a Digital camera in the near future. i have been told that you really only need about 4 or 5 megapixels for pretty much anything. The only time you would need more is if you plan to plow up the pictures to a poster size print. is this the case?
If I want to crop a picture and enhance only a certain portion, is this where I will need more megapixels. I do not understand this concept and am trying to get all the feedback possible. I want a camera (point and shoot) that will give me the best pictures possible. Any thing you have to offer or suggest will be greatly appreciated.
Thanks!

Answer 1

It all has to do with the size you want to print. More pixels gives you more flexibility to print bigger. Or more flexibility to crop out a portion of an image and still be able to print it larger.

Most home and commercial printers need at least 200 pixels per inch (ppi). So if you want 8x10 in prints, you need

8x200=1600 pixels wide by 10x200=2000 pixels high

That's 1600x2000=3,200,000 pixels or 3.2 megapixels.

So for 8x10's you need a minimum of a 3.2 MP camera. Printing any bigger than that will start to get blurry.

You need at least 7 MP to print 11x17's. So the limits occur long before "poster size". Still, most people don't print even that big, so 4 or 6 MP works out just fine for them.

Here's another view:

Digital pictures are made out of small rectangles called pixels. Our eyes cannot see the individual pixels as long as they are small, about 1/300th of an inch or smaller.

If you take a picture with a certain number of pixels, say 3.2 MP, then that is the most clear pixels you will ever have in that picture. The number of pixels is set.

When you make large prints, the software will stretch out those pixels to fit the size you requested. As the pixels stretch out they get bigger. If the print is so big that the pixels get bigger than 1/200th inch, it starts to look blurry to our eyes.

If you make the print big enough, you will actually be able to see the individual pixel rectangles.

Bottom line: Buy enough MP in your new camera to accomodate the likely print sizes you will use. If you want to do a lot of cropping, buy more.

More MP's are not much more expensive, although they do take up more space on your memory card and hard drive.

But MP's are not the primary contributor to picture quality. The lens, focusing capability, exposure capability, and internal processing are much more important. MP's only let you print bigger and crop more. Period

Good Luck

Answer 2

Well, if you want to print up to say a size of 8 by 11, then a 5 megapix camera is fine.

You can not expect to infinitely blow up any image. There is always a limt beyond which images get quite blurry.

You could go for a zoom lens or telephoto lens. These are available both for SLR and for some Point and Shoot.

To figure the camera assume between 15o to 300 dpi (dots per inch) to compute the size of image required.

At 150 dpi, you need an image size of 1200 by 1650 pixels.

At 300 dpi you would need an image size of 2400 by 3300

The higher the dpi the clearer the print..

Answer 3

well ...5.5 Megapixels is good enough up to 8x10" (inch) print size. Most of the photo lab printers (Noritsu for instance) are using 300 dpi to 400 dpi. Where dpi stand for dots per inch.

So you may want to have more pixels if you plan to print much bigger sizes (so called "enlargements") or if you intend to crop the picture (so you will loose some pixels).

If you want to know if your camera has enough pixels, keep in mind that a photolab printer is asking for at least 300 dpi (dots per inch). So that you can aproximate the maximum paper size what you can cover :
H pixels / 300 dpi and W pixels / 300dpi
if H=8inch W=10 inch
8x10" you will need at least:
8x300pixels=2400pixels per 10x300=3000pixels =>
2400pixels x 3000pixels = 5.5Megapixels camera.

5x7" = 5x300dpi per 7x300dpi => 1500x2100pixels = 5 Megapixels is good enough.

Answer 4

The more pixels, the higher the resolution. Pixels are getting cheaper and cheaper. Yes, if you want to crop and enhance, the more pixels the better. Note that 'digital zoom' is about the same as doing that, but without any enhancing. Go for more optical zoom. If you plan on having prints larger than 4"x6", I'd go for 6+ megapixels

Answer 5

More mega-pixels is generally better.
3MP is plenty for a 5x7 inch print.
6MP is good enough for an 8x10 inch print.
For poster size prints, you'd really want at least 10MP.
With regard to cropping, say you have a 6MP camera. That means that every picture you take will consist of six million (mega) colored dots (pixels). If you have a specific picture where you only want to use the central 50% of the image, you'd only be using 3 million dots... and that reduces the recommended maximum print size.
So MP limits the print size.
Image quality on the other hand, is determined by the quality of the lens. And unfortunately, there is no way to quantify that... you'll have to read reviews. Two great sites for reviews are:
http://www.steves-digicams.com/hardware_reviews.html
and http://www.dpreview.com/reviews/default.asp?view=alpha
and in general, everything by Kodak and Canon is very good. I'd start by looking at some of their cameras in your price range.

Answer 6

Well it does matters, it is perceptible if you compare a picture taken by a 2.5 megapixels and a 5 megapixels, not a difference if you compare higher from 5 by now...

Answer 7

Depending on where you going to use your pictures ...

e.g. Web or Hard copy?

~ 3.5 and below for web purposes ...

~ 3.5 and up for Hard copy ...