The benefits are reduced file sizes and the ability to calculate the zoom level from the image's dimensions, if not included in its meta data. Some camera firmwares store lossily digitally zoomed images with accordingly reduced dimensions (width and height) rather than upscaling it to the original raster resolution. Magnification in deteriorated digital zoom zone is 72×: 10 = 7.2×, the bigger the number, the worse the image Zoom 72×, Optical zoom 10× and Digital zoom 7.2× taken in full resolution 16 MP, but resize to 2 MP for uploading, ISO 800, 1/680, F/14.0, more noise, but the detail is more clear. The table below shows the not-deteriorated zoom limit for some megapixel (MP) image sizes of a particular camera with optical zoom 24x, and digital zoom 4x for its maximum capability:
By reducing the image size, digital zoom occurs without image deterioration of the output image, and some cameras have a "not-deteriorated image" mode or an image deterioration indicator. Digital zoom uses the centre area of the optical image to enlarge the image.
Not-deteriorated zoom limit Īn optical zoom camera can be zoomed to its optical limit, and further zooming is sometimes allowed by digital zoom. Professional cameras generally do not feature digital zoom. Full-sized cameras generally have an optical zoom lens, but some apply digital zoom automatically once the longest optical focal length possible has been reached. Lower-end camera phones use only digital zoom and do not have optical zoom, while many higher-end phones have additional rear cameras, including fixed telephoto lenses that allow for the simulation of optical zoom. In cameras that save in a lossless format, resizing in post-production yields results equal or superior to digital zoom. In cameras that perform lossy compression, digital zoom is preferred to enlargement in post-processing, as the zooming may be applied before detail is lost to compression. Digital zooming may be enhanced by computationally expensive algorithms which sometimes involves artificial intelligence. It is accomplished electronically, so no optical resolution is gained. It is accomplished by cropping an image down to an area with the same aspect ratio as the original, and scaling the image up to the dimensions of the original. Typically, the digital zoom is not available until the optical zoom has been exhausted.ĭigital zoom is a method of decreasing the precise angle of view of a digital photograph or video image. No quality is lost however, with the lens zoomed-in optically for the bottom photo. Digital zoom has been used to create the middle photo from within the top photo.
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