Because when the aperture value is set large (F=2.0), only the subject in the photo is clear, and other foreground backgrounds are blurred. When the aperture value is set smaller (F=8.0), any object in the photo is clear. The setting of aperture value is selected according to the atmosphere you want to create. This setting can show the details of jewelry more clearly.

Supplement: The larger the aperture, the brighter the photo, and the smaller the aperture, the darker the photo. You can choose the appropriate aperture shutter combination according to the atmosphere you want to create. Iso: iso: the sensitivity of an iso camera. Ordinary cameras are: 5064 100200400800, etc. The bigger the number, the brighter and darker the photo. However, consumer DC does not control ISO very well. When ISO is above 200, there will be serious noise in the picture, which is very ugly. So generally speaking, ISO below 100 is used for shooting, and sufficient light is obtained through the combination of shutter, aperture and tripod.