How big is the gap between telephoto and entry SLR?

The size of sensors varies greatly. The entry SLR is in APS format, and the sensor area is about 24 mm x16 mm, but the telephoto lens is usually only 1/2.3 inches, which is much worse in thermal noise suppression and diffraction effect control. The image processor of entry-level SLR is also more advanced, which is superior to telephoto lens in both speed and final imaging, so the continuous shooting performance of entry-level SLR is superior to telephoto lens and card machine. Needless to say, the lens is not only a problem that the aperture is not aperture, but the key point is that even the minimum aperture of the entry-level SLR head can be f22, f35 or even smaller, which can not be done by ordinary card machines and telephoto machines. Even the optical quality of low-end ferrule is better than that of ordinary card and telephoto. The longest shutter of ordinary telephoto lens and telephoto lens is 16s (some powerful machines can have 30s and 60s shutters), but the entry-level SLR has a B-door and a T-door, so both telephoto lens and telephoto lens are dumbfounded when shooting the orbit of stars. Also, when shooting all over the sky, do you dare to adjust the ISO of cards and telephoto machines to above 800? Then it's really all stars, and everything without stars becomes stars. However, the APS format photosensitive element for entry-level SLR can easily reach 800. ..... Entry-level SLR is also better in image quality, not to mention the low price of entry-level SLR, with more than 1,000 ordinary telephoto lenses and 3,000 to 4,000 cheap entry-level SLR. There is a price gap, but it is still worth it for those who plan to take entry-level photography. As for just a general pat, forget it .../kloc-more than 0/000 telephoto machines and card machines are enough.