Tom,
Beyond your question here, you seem to also have a misunderstanding about the megapixel rating of your camera and the related storage size a given image will occupy. So, here’s just a bit more info:
An RGB color image has a 24-bit (3 byte) per pixel color depth. So a 1×1 pixel image requires 3 bytes to store the data. A 3 megapixel camera provides approximately 3 million pixels of image data, thus each image requires 3 million x 3 bytes, or 9 million bytes to store the data. As 1 kilobyte (KB) is defined as 1024 bytes and 1 megabyte (MB) is 1024 KB, then your camera produces an image whose file size is 9,000,000 bytes x (1KB/1024 bytes) x (1MB/1024KB), or 8.58 MB. Take 30% off that, and you’ve got 6.15 MB. So, yes, I’d say you’re right in the ballpark with the file size you observed, and you either took of a little less (~26.5%) than you think or your camera produces a usable image of slightly more (~3.1MP) than 3 megapixels.
Regards,
Daryl
Hi Daryl,
Thanks for that very clear and informative explanation. My estimate of how much I cropped was just ballpark, so that file size seems to fall right in line.
