If checking that the calculator matches your cameras Div8 dimensions, the specifications for megapixels and aspect ratio are rounded nominal numerals which will be close, but might not compute the exact precise image size in pixels (due to rounding - camera specifications are rounded values.) If not exact, the best try the significant digits is to first enter the second option of actual sensor dimensions in pixels instead of Megapixels to compute the actual precise megapixels and aspect ratio values for your camera. It will show at least four significant digits, if applicable (fractional trailing zeros are not shown or needed). The calculator is written for megapixels (first option), but to aid seeing at least four accurate significant digits, the Image Size option was added to determine actual precise values of megapixels and aspect ratio for your camera. So the computed pixel dimensions could be just a few pixels off, but a few tenths of a percent will certainly be close enough for practical purposes. To recompute those four exact digits of pixel dimensions likely requires Megapixels and Aspect Ratio to also be four significant digits because in math, the final answer can only contain as many accurate significant digits as the least precise value computing it. Whereas megapixels and aspect ratio are rounded specifications, only two or sometimes maybe three significant digits (not totally precise). Pixel dimensions are exactly known and are typically 4 significant digits. It computes actual megapixels and Aspect Ratio with greater precision. The second option (Image Size) is provided when pixel dimensions are already known, and might be all you know with any precision.Likewise, Aspect ratio is rounded to a nominal value too, but the precise actual value is image width / height, in pixels. The camera specifications round off megapixels, but the precise value is image width × height in pixels. And then actual camera sensors typically round to multiples of 8 pixels (evenly divisible by 8). Adding or Subtracting one pixel to width or height can be thousands of pixels in the other dimension, so the rounded result necessarily can affect the megapixel total somewhat. Since images cannot be dimensioned in fractions of pixels, the result rounded to whole numbers is then shown (in green). Calculated pixel dimensions (in gray text) are excessively shown out to a few decimal places (even if pixels cannot have fractions), to show that the megapixels come out exact, matching the same as entered. The first option (Megapixels) calculation is the regular option.There are two calculator options, and the results for each case are: But pixel dimensions of images cropped or resampled in your editor have low odds to be evenly divisible by 8. Image pixel dimensions of the actual camera images should be Div8, however specifications for megapixels or aspect ratio are rounded. But resampled or cropped images might have any dimensions, likely Not divisible by 8.ĭiv8 - Images resized in photo editors can be any dimensions, but camera sensors actually use pixel dimensions which are evenly divisible by 8, no doubt to match the JPG 8x8 compression blocks (I'll call that value Div8 here).
Cameras create pixel dimensions evenly divisible by 8 (I will call it Div8, and is only size shown if already Div8 is specified). One pixel difference of width might affect a few thousand rows of height.ģ. Dimensions rounded to whole pixels, necessary for real pixels, but which changes megapixels a little. Exact computed dimensions (matches specified megapixels exactly, even if pixels cannot be fractional).Ģ. Three values of pixel dimensions may be shown, in the order of:ġ. Your results will come out closer if entering your actual real numbers instead of the rounded camera specifications.īut there are ifs and buts about everything, so this is trying to explain why the result megapixels may not exactly match your camera's specified megapixels. Megapixels use the conventional 1K = 1000, and NOT the 1K = 1024 used by memory chips.Īspect Ratio is exactly computed by image dimensions in pixels, Aspect Ratio = Width / Height. Megapixels are exactly computed by image dimensions in pixels, megapixels = Width × Height. The calculator will show the precise format, as like 1.3315:1 format. Aspect ratio 4:3 is 4/3 = 1.333, which can be entered here as:Ĥ:3 or 1.333:1 or 1.333, or as 1.338 if and when more precise.
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