1/2/2023 0 Comments Digital works photographyA digital sensor's true power comes from its ability to integrate, or collect, photons over much longer time periods than the eye. It is the time sampling with long exposures that really makes the magic of digital astrophotography possible. A digital camera is almost as sensitive as the eye, and both are much more sensitive than film, which requires many photons for a detection. It requires several photons for a detection to be sent to the brain. It can detect a single photon, but this information is not sent along to the brain because it does not exceed the minimum signal-to-noise ratio threshold of the noise filtering circuitry in the visual system. The eye is a relatively sensitive detector. This is why we can see more details through a telescope if we stare at a faint object for a period of time. Under low light conditions, the eye's exposure, or Integration time can increase to several seconds. Our eyes also sample the world in a way that can be thought of as a "time exposure", usually on a relatively short basis of a few tenths of a second when the light levels are high as in the daytime. Time sampling means we make an exposure of a given duration. If there are enough samples, both spatially and tonally, we perceive it as faithful representation of the original scene. Tonal sampling means the continuously varying tones of brightness in nature are broken down into individual discrete steps of tone. Spatial sampling means the angle of view that the camera sees is broken down into the rectangular grid of pixels. There are millions of these individual pixels in the sensor of a DSLR camera.ĭigital cameras sample light from our world, or outer space, spatially, tonally and by time. Each photosite is usually called a pixel, a contraction of "picture element". It is made up of a grid of tiny photosites that are sensitive to light. Photons from the sky are gathered by a telescope and focused on the sensor of a digital camera where photo-electrons are created, stored during an exposure, and finally digitized and turned into numbers that we work with on a computer.Ī digital camera takes light and focuses it via the lens onto a sensor made out of silicon.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |