Calculations with Optical Instruments
Digital Camera
Calculate resolution and aspect ratio of photos made with a digital camera. Enter either the number of megapixels and the ratio or the number of pixels of the photo in length and width.
The formulas for the resolution in pixels x*y for format a:b and p pixels are:
x = √ p * a/b , y = p / x
Megapixels are the number of pixels in length times the number of pixels in width, divided by a million. An image measuring 3000x2000 therefore has 6 megapixels. Common formats for a digital camera are 3:2 and 4:3. 16:9 is less common. 3:1 is panoramic format.
Calculate the file size of a camera and how many photos will fit on the memory card. Please enter the number of megapixels of the camera. Size per megapixel for RAW and compression ratio RAW/JPG are predefined and can be adjusted. From these three values, the average size and maximum size of an image can be calculated. If you specify the space on the memory card, you can calculate how many images will fit on it.
Size and compression vary strongly with cameras and settings, here are given approximate values. The available size on a memory card often isn't identical to the indicated size, but smaller. Connect the card to your computer to see the real size. Size differences between images are due to different richness of detail. A photo with a large, monochromatic area (e.g. blue sky) has a smaller size. This difference is stronger for JPGs than for RAWs. Here, a ratio average to maximum size of 2:3 for JPG and 9:10 for RAW is used. With JPG & RAW, the photos are saved in both file formats, so the storage space required is the total of the JPG and RAW files.