Some cameras in the Sony Alpha range uses SLT (Single Lens Translucent) technology, while the majority of cameras above compact level use DSLR ( Digital Single Lens Reflex) or SLR. Another Choice of camera is the MILC (Mirrorless Iterchangeable Lens Camera or Electronic Viewfinder with Interchangeable Lens).

An SLR uses a mirror to reflect the image that will be captured in a viewfinder. The reflex mirror reflects the light into a pentaprism from the exact angle of 45 degrees. It is projected onto a matte focusing screen The image is then projected to the eyepiece via a condensing lens and the internal reflections from the roof of the pentaprism. When the shutter button is pressed, the mirror flips upwards, and projects the image through the shutter, onto the sensor, where it is captured. The shutter  then closes and the mirror returns to a position of 45 degrees.


DSLR  Advantages over SLT

  • more light enters sensor
  • brighter viewfinder
  • optical viewfinder
  • (generally) Longer battery life


  • Mirror is up so if scene changes slightly it will not be updated.
  • No viewfinder update at high shooting rates
  • Can cause eyestrain due to bright electronic viewfinder
  • mirror can become soiled, and SLT mirror can be taken out for cleaning
Sony SLT cameras have mirrors, but they are not articulating, and are semitransparent (translucent). This means that a third of the light is redirected to the viewfinder. The remaining light goes to the sensor


  • More resistant mirror
  • Good viewfinder brightness
  • more compact body
  • live view during video
  • less camera shake (no mirror movement)
  • potential for faster continuous shots (and as a direct result, high sports and action photography potential)


  • No optical viewfinder
  • Less light reaches sensor (theoretically, though users do not report noticing this)


There is a third player. It is time to get EVIL!!!!!

This camera is the intermediate between DSLRs and compact (point and shoot) cameras.

It has acquired various names, including Mirrorless interchangeable lens camera (MILC), Compact System Camera (CSC), Mirrorless System Camera (MSC), Digital Single Lens Mirrorless (DSLM) or Electronic Viewfinder with Interchangeable Lens (EVIL). The final name is misleading  because it does not mention the mirrorless system, and also the abbreviation does not give a very inviting effect. They are also called Micro Four Thirds Cameras.



  • small with large sensor (although not as large as DSLR sensor. Also, recently some new ones have been released with compact-camera-sized sensor)
  • Shutter activation is quieter
  • Sturdier (less moving parts)


  • Contrast detection autofocus (not as effective)
  • Incompatibility with most lenses
  • No optical viewfinder
  • smaller sensor
 Compact Camera (vs DSLR)
  • smaller
  • pocket size (mostly)
  • lighter
  • May or may not have optical viewfinder
  • smaller sensor
  • slower autofocus
  • Less control
  • fiddly
  • Many lack a manual exposure mode
 How do you feel about theses systems, which do you use, and why? Please comment below.