How many photos can my digital camera take?
By Alfred DeBat

“How many photos can my digital camera take?” That sounds like a simple question, but it isn’t. Since digital cameras employ memory cards, rather than film, three important factors are involved in the number of pictures that can be taken by a particular camera.

1.	Your camera sensor’s maximum resolution.
2.	The setting of the camera’s resolution for your pictures.
3.	The “size” of your camera’s memory card.

    Let’s use a typical point-and-shoot digital camera as an example. The Canon PowerShot A95 is a 5-megapixel sensor digital camera. That means the sensor has 5,000,000 pixels. If you shot every photo at the maximum resolution of 2,592-by-1,944 pixels, at the most detailed image setting, that would provide the sharpest possible picture and allow you to make prints larger than 11-by-14 inches. But, the actual number of pictures possible also depends upon the other two factors.
    When the camera is at its maximum resolution of 2,592-by-1,944 and on the “Super-fine” setting, you could take 11 photos on the 32 MB memory card that comes with the camera. Changing the setting to “Fine,” you could take 21 pictures, and at the “Normal” setting you would have space on the card for 43 images.
    However, you can reduce the sensor resolution to 2,048-by-1,536, 1,600-by-1,200, and 640-by-480 pixels on this camera. Each time the resolution is lowered, you limit the sharpness and the maximum size of print enlargements that can be made. For example, again, with a 32 MB card, if you set the resolution at 640-by-480 pixels and Normal detail, you could take 672 pictures. But, unfortunately, really sharp prints of these pictures could only be about 2-by-3 inches.
    Why would anyone want 640-by-480-pixel resolution photos? If you aren’t interested in making prints, the resulting images will look okay on most computer screens, which operate on much lower resolutions than photo-quality printers. Also, the smaller size image files are easy to send by e-mail.
If you want large, sharp prints, what can you do to increase the number of photos? Purchase a new memory card with more “real estate,” since memory cards are available in bigger sizes.
    Check your camera’s specifications online at the manufacturer’s website and locate information on how many photos can be made at specific resolutions for a memory card. Then, it only takes a little math to learn what a card upgrade will give you. For example, with the Canon PowerShot A95 in Super-fine resolution you can capture 11 photos on a 32 MB memory card. That translates to 22 photos with a 64 MB card, 44 photos with a 128 MB card, 88 photos with a 256 MB card, and 176 photos with a 512 MB card. Or, it could mean thousands of photos at lower resolution settings.
In any case, don’t make the mistake of one digital photographer, who set his camera for the minimum resolution and could only create a dollhouse size photo album of all his vacation pictures.