These are the best camera phones under Rs. 20000. (You can also check the complete specs with links).
Oppo F3 Plus 6GB RAM - The Oppo F3 Plus provides a 16MP primary camera, which is accompanied by dual-color LED Flash and Exmor-RS CMOS sensor for superior quality photography. However, the principal attraction of the device is the 16MP+8MP dual camera setup up front, which offers a f/2.0 aperture and comes with screen flash to aid low-light selfies.
Nubia Z17 Mini Limited Edition - The Nubia Z17 Mini Limited Edition offers a great photography experience with its dual (13 MP + 13MP) primary cameras. Other camera features are an Exmor-RS CMOS sensor, phase detection autofocus, continuous shooting and High Dynamic Range mode (HDR). The 16 MP front camera that gets a 2.0f aperture which is capable of producing excellent quality selfies.
Asus Zenfone 3 ZE552KL - The device sports a 16MP rear camera that has OIS, phase detection as well as laser autofocus, RGB sensor, Exmor-RS CMOS Sensor, dual tone LED flash and has an aperture of f/2.0. Accompanied by an 8MP front-facing camera for selfies and video calls. Both, these cameras can capture brilliant quality shots in varied lighting condition.
The Huawei Nova 3i does not have a removable battery. The non-removable battery helps the manufacturer create a sleek design, lightweight and good looking product. It also helps with recovering a stolen phone. A removable battery can be taken out by a thief to stop the phone from tracking its movement. You need to visit the customer care to get the battery replaced.