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View Full Version : Digital camera question: How many pixels in a megapixel?



*Sparky*
25-06-2003, 10:47 PM
Howdy folks,

Got some junk mail today from Time magazine offering a free digital camera with a 1 year subscription. Thought it might be worth paying the $144 to get both. Obviously the camera will be a cheapy, but good for a play, being my first.

Camera details:
- High resolution 352 x 288 pixels
- 16mb memory
- Takes 19 images
- complete with software, USB connector cable etc

Question: Most digital cameras talk about mega pixel resolutions. Would I be correct in assuming that 352 x 288 is less than 1 mega pixel? and the quality of the snaps will be s**t?

Cheers.

Iain Walmsley
25-06-2003, 11:00 PM
The quality of a digital camera iamge is dependant on two things, the resolution, and the sheer number of pixels. For example, a 352 x 288 pixel image would be reasonable size (cm x cm) but crap quality if viewed at 25dpi (dots per inch). However the same image would be of excellent quality but miniscule if viewed at 1200dpi.

A Mega pixel is to the order of a million - I cant remember if digital imagery uses metric Mega (1,000,000) or the Binary million (2^10 or 1,048,576.

To compare this camera to a reasonable digital camera, the camera on offer is 101,376 pixels, or roughly 0.1 MegaPixel... A picture with no digital zooming, looks photographic at 2.7 MegaPixel for a 5x6 inch photograph.

Only you can decide if you think the camera is worth it ;-)

Iain

Elephant
25-06-2003, 11:12 PM
Simple answer here....

Don't buy it if you want to print images. I still have a 640x480 digital camera here. (Kodak DC20) which I don't use anymore now. Even a 6"x4" print looks very blocky. OK for an image over the Internet but don't even think about doing anything other than screen resolution like 72 dpi.

I now have a 2.1 Megapixel camera which does all I have to have. I would LIKE to have a 5 Megapixel camera but don't have the dollars.

YMMV.

*Sparky*
26-06-2003, 12:00 AM
Thanks guys for your prompt and informative replies. Good to see people who know what they are talking about.

I guess I'll put the $144 towards a $329 2.1 megapixel job, and miss out on free firelighters for a year.

Thanks again.

Iain Walmsley
26-06-2003, 12:22 AM
A 2.1 Megapixel job will give you standard sized photos that are virtually indestinguishable from actual photos - unless you have a very well trained eye - I can only sometimes spot the minute differences.

Another thing to look for is a reasonable optical zoom length. Any magnification given ie 5x, doesnt mean 5 x magnification, it means that the telephoto magnification is 5x the wide angle... but as most cameras have a wide angle equivalent to a 35mm lense, ie approximately 0.5x reality, a 5x zoom lense will let you take photos at 2.5x reality... give or take, its not quite accurate but close enough.

A high optical zoom, means you get a quality image at magnification, if you have low optical zoom, then you have to use digital zooming to enhance the zoom of the photo. The result is a lessening of quality, as digital zooming is forced to "make up" the extra information.

Enjoy your camera though, I wouldnt be without mine, one of the best purchases I ever made.

Iain

rsnic
26-06-2003, 12:27 AM
Im not exactly sure about this but it would make sense that the megapixel like a megabyte is 1,000,000 pixels. Therefore the largest image a camera can make is its rating e.g.
1280 x 1024 = 1310720 pixels = 1.31 mega pixel
since an image is measured by how many pixel it is high and wide.
therefore a 352 x 288 = 101376 pixels = .1 megapixels

*Sparky*
26-06-2003, 12:31 AM
Your getting me excited now. I cant wait to buy my camera now. At least with a digital there is no expense in buying and developing film anymore. Thats the hard part, remembering to get them developed.

Cheers Iain

Iain Walmsley
26-06-2003, 12:42 AM
Actually, a Megabyte ISNT 1,000,000 Bytes. That was my point. Binary prefixes relate to a base 2 number system, not base 10.

- Kilo in base 10 means 10^3, in base 2 it is 2^10.
- Mega in base 10 means 10^6, in base 2 it is 2^20.
- Giga in base 10 means 10^9, in base 2 it is 2^30.

Basically, the magic number to remember is 1000 for base 10, and 1024 for base 2, some computer references use base 10, some use base 2, and the decision is sometimes fairly arbitrary.

Iain

rsnic
26-06-2003, 01:19 AM
Pixels are not based on the binary digit though.

Poppa John
26-06-2003, 03:19 PM
Sparky. Go for it friend. We have a Kodak CX4200 with the camera dock to connect it to the computer. The software that goes with it is Magic. Tried another Brand but took it back, far too complicated with sort of English. Would not be without a Digital now. Maryann takes pictures of anything & everything, puts them in the computer, can Play/Adjust/etc & save them, delete them, print them on plain paper or photo paper, E-mail them!!! What more could you want?
Poppa John :D :D