Sony Cyber-shot DSC-R1

Advantages

• since there is no mirror between the sensor and the lens, the lens can be positioned closer to the sensor, which improves the performance at wide angle. The back focal length of the DSC-R1 in wide-angle mode is 2.1 millimeters, which is much smaller than the wide angle back focal length found typically in DSLRs
• the image in the EVF and LCD screen is bright and the light is amplified. An optical viewfinder instead does not amplify the light, so that it becomes difficult to frame and manually focus when there is not sufficient light.
• Less dust problems, since the DSC-R1 can't change lens; nevertheless dust can enter while zooming for the volume change 'pumping' the air in and out.
• silent operation, as there is no swinging mirror or physical shutter system
• as there is no shutter system there is essentially no limit to flash sync; photographs can be taken in broad daylight with fill flash at speeds of 1/1,000" or faster
• fewer movable parts, therefore greater reliability
• With histogram screen display 'on' the screen/viewer displays the output from the processor, enabling very accurate exposure control - Full-time Live Preview.
• supports RAW

  Disadvantages

• no interchangeable lenses: the supplied lens only covers the 24–120 mm zoom range.
• no optical viewfinder. Furthermore, there is some small time shift, i.e. the image appears with a small delay.
• Low frame rate and slow contrast-detection autofocus.