I am a total newbie when it comes to any kind of photography.

I would like to invest in a digital camera, mostly for the usual family photos etc and to store on CD.

My question is can somebody give a summary of the ratio of images to memory (Mb for example) at different image qualities. When I mean different qualities, please dont get technical on me. I suppose it can be simplified down to catogories such as 1. Professional, 2. Home Printable, 3. Computer Viewable, 4. Web publishable, etc. Though this is rather crude, it gives a better idea to somebody like me.

One of the main reasons for this is that when I go on holiday or similar, I will know how many memory cards I'll need to take in relation to estimated pictures to be taken.

Any replies would be greatly appreciated.

Regards,

-- red (red@sevenk.force9.co.uk), April 09, 2000

Answers

I don't think you can be that general about it, since different cameras have different resolutions(640x480, 800x600, 1024x768, 1280x1024, 1600x1200, 1800x1200, 2000x1536 etc.) & compression ratios(like fine 1/4, normal 1/8, basic 1/16 for some cameras) and memory capacities vary based on the size of the card you buy.

How about trying the "teach a man to fish" approach?

H x V = Resolution Resolution * 3(bytes/pixel) = Raw File Size Raw File Size x Compression Ratio = File Size Capacity / File Size = Number of Images

Capacity = MB x 1024x1024 or 8MB x 1024x1024 = 8,388,608

For example:

1280x1024 = 1,310,720 1,310,720 x 3 = 3,932,160 3,932,160 x 1/16 = 3,932,160/16 = 245,760 8,388,608 / 245,760 = 34.13 images

1600x1200 = 1920000 1920000 x 3 = 5760000 5760000 x 1/16 = 360000 8388608 / 360000 = 23.30 images

Bear in mind that manufacturers tend to play fast and loose with the compression ratios and depending on the subject, you often end up with an even smaller file for a given compression ratio. For example, in 1/8 compression(normal) on my PDRM5, at 1600x1200 I should only get about 12 images, but it always ends up around 16 images or more like 1/11 (or more accurately, 11:1 )compression...

If you're interested in cameras reviewed by Imaging Resource, Dave usually (always?) provides a table of image sizes and capacities in his reviews. So you might start there and leave the hard work to Dave... :-)

Good Luck.

-- Gerald M. Payne (gmp@francomm.com), April 09, 2000.

Try going to the digital camera reviews on this site.. The reviews have spec sheets that will tell you how many pics you can get with a specific camera at the different resoulutions.

-- Chip (buflerchip@sisna.com), April 09, 2000.

Grrrrrr! I hate the formatting of this $%&#$% forum sometimes.

What I meant was:

H x V = Resolution

Resolution x 3 = Raw File Size

Raw File Size x Compression Ratio = File Size

Capacity / File Size = Number of Images per card

-- Gerald M. Payne (gmp@francomm.com), April 10, 2000.

Red, Gerald is right that there is no good, simple way to break image qualities down into the categories you asked for. there is just too much involved, especially size (e.g. size of the print and size you want the pic to be on the web). To help decipher Gerald's answer, this site has a very helpful article that includes what resolutions will be good for printing at various sizes and with various printers. the url is: http://www.imaging-resource.com/ARTS/DDARK/DDARK.HTM

-- Joel (jhb01@comp.uarkk.edu), April 10, 2000.