Why is the aperture of 2.8 so popular? My dog's head is not 2.8 aperture, can you make up a smaller aperture? The photo effect is the same?

1 is not a lens with a constant large aperture, but its advantage is only a large aperture. Because of the high production cost of large aperture lens, firstly, manufacturers have different positioning of large aperture lens. For large aperture lenses, they invest more, including lens groups, and the lens material is different from small aperture or floating aperture lenses.

2. If the aperture is used alone, the impact is nothing more than dark light exposure and depth of field. Of course, improving the sensitivity can make up for the problem of small aperture, but the image quality will definitely decline and the noise will increase, which will pay a price. Either use fill light photography, use a tripod, or fill light. The situation is different in different scenes. For example, small and important conference photography can not use flash, tripod is basically useless, because people's subtle movements have an impact, so we can only increase the aperture and improve the sensitivity. . . As for the depth of field, if the requirements are not high, post-processing can cope, or telephoto end or close-up can reduce the depth of field.

Generally speaking, according to personal needs, we usually buy suitable lenses for what we shoot.

I usually shoot this kind of meeting I mentioned, so I have no choice but to use a high-sensitivity camera and a large aperture pan/tilt.