DSLR camera used a technology called phase detection and its work quiet similarly to that of a rangefinder. When the subject or scene is out of focus, the AF module detects a split image. Mirrorless camera used contrast detection to detect the highest contrast. Contrast detection is slower than phase detection when light condition is low. So DSLR have the advantage here. Now few mirrorless camera have both phase and contrast detection sensor (Hybrid Sensor) built into image sensor and can be used both to refine their auto focus.
A DSLR optical view finder shows to you what the camera will capture. Mirrorless camera shows the object preview through LCD and EVF (Electronic View Finder). DSLR Camera light passing through the lens is reflected off a mirror and into the viewfinder, which enables you to shoot while viewing the actual image. The advantage of this is that you can track moving objects more easily, and also have a more accurate view of colors. On the other hand, since the mirror is necessary for reflecting light, there is a limit on how compact the camera can be made. EVF Projects the image captured by the image sensor onto a small LCD panel. So, if you are shooting in good light, both types camera will perform well. If you are often shooting in low light or other challenging conditions, though, a DSLR will be easier to shoot with.
Both types of camera can capture high quality image with similar resolution and amount of noise.
DSLRs can’t use phase detection sensor while capturing the vedio.So this time camera use less accurate slower contrast detection method. Some DSLR camera has option phase detection on the sensor, they are Canon 80D and Rebel T6s
Increasingly, mirrorless cameras can capture 4K, or Ultra HD, video with four times the resolution of HD footage. Currently, only higher-end DSLRs, such as the Nikon D7500 and Canon EOS 5D Mark IV shoot 4K/Ultra HD video. Still, video professionals, if they use a still-photo camera at all, tend to prefer DSLRs, because the cameras have access to a huge range of high-end lenses.
DSLRs offer longer battery life than mirrorless.DSLR can shoot without LCD or an electronic view finder.LCD and electronic view finder consume a lot of power, hence mirrorless camera battery life is too short. Mirrorless camera are looking small, so battery cell are small.
With DSLR can use variety of lens and price as low to as high. But mirrorless camera has few lens and all are expensive.
Size and Weight
DSLR camera body and weight are comparatively lager then mirrorless camera. DSLR camera are use mirror and prism, hence body size and weight are larger. A Mirrorless camera body and weight are smaller and easy for carry anywhere. Now some DSLR offer smaller body and light weight like Nikon D3500