ed,af-s dx,g gibi değişik lens kısaltmaları ne anlama geliyor

 Canon Specific Lens Types and Abbreviations 
   
  EF : Lens mount designation for Canon's current camera system. Stands for Electronic Focus. 
   
  EF-S : Lens mount designation for Canon's current APS-C digital SLRs (reduced sensor size), for example the 20D, 350D, and 300D models. The S stands for "short back focus," implying that the rear element of the lens is closer to the sensor than with regular EF lenses. EF-S lenses will not mount on Canon film SLRs or Digital SLRs that do not have an EF-S mount. 
   
  TS-E : Tilt-shift lens, for control of perspective and depth of field. 
   
  MP-E : Macro Photo Electronic. These lenses do not have autofocus, the "electronic" refers to the electronic aperture control. Specialised lenses designed for macro photography. 
   
  L Lenses : L refers to Canon's professional range of lenses. Many people take the L to stand for Luxury. Purchases of such lenses can lead to 'L Fever', a condition where all future lense purchases must be L class. 
   
  IS : IS refers to Image Stabilisation, Canon's anti-shake feature. Also known as VR (Vibration Reduction - Nikon), OS (Optical Stabilisation - Sigma). 
   
  USM : USM refers to the autofocus motor. Ultrasonic Motors (USM) are piezoelectric and offer very fast and silent autofocusing. There are two types: A standard cheaper micro-USM which just replaces the regular electromagnetic AFD motor, and a Ring USM (internal focus) which is much faster and also incorporates fulltime manual focus overide without leaving AF mode (or damaging the focus mechanism). 
   
  AFD : An older type of AF motor, AFD (Arc-Form drive) is generally slower and noisier than USM. 
   
  A note about the maximum aperture The maximum aperture in a 135mm F/2 lens is (135/2) = 67mm. This means the hole that lets the light in opens up to 67mm. This explains why lenses with larger apertures are more expensive: they require more glass inside larger barrels. 
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  Sigma Specific Lens Types and Abbreviations 
   
  EX : An abreviation for the "Excellence" range of lenses. These lenses are similar to Canon's L series, claimed to be superior in build and optical quality to regular lenses. Like the L series they have a distinctive exterior. 
   
  DG : A DG lens can be used with both 35mm SLR and digital SLR cameras. DG refers to additional optical coatings that are meant to minimize reflections of light off the sensor itself. 
   
  DC : A DC lens is designed so the image circle matches the smaller size of a digital SLR's image sensor compared to a 35mm frame. These are typically lighter than DG lenses but are not suitable for 35mm SLRs. 
   
  ASP: An aspherical lens, which is more compact than conventional lenses. 
   
  APO: APO or apochromatic lenses are made using a low dispersion glass to reduce chromatic aberration. 
   
  OS: Optical Stabiliser. More or less identical to Canon's IS and Nikon's VR. 
   
  HSM: "Hypersonic Motor," which in the same way as Canon's USM is used to power the autofocus mechanism and is generally quieter and faster than conventional electromagnetic motors. 
   
  RF: Rear focus lenses move the rear lens elements delivering faster, more quiet focusing. 
   
  IF: Inner focus lenses move the middle lens elements which does not change the lens' overall length when focusing. This results in better stability, which is useful for telephoto shooting. 
   
  DF: A dual focus lens. The focus ring on the lens pushes forward and backwards dis-engaging it so it does not rotate during autofocus. 
   
  Conv: These lenses are compatible with Sigma's teleconverters without and retain proper automatic exposure function. 
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  Tamron Specific Lens Types and Abbreviations 
   
  Di : Digitally Integrated Design. This is the same as sigma's DG lenses and simply has extra coatings on the glass. 
   
  Di II : Lenses for Digital SLR Cameras Only (cameras with a APS-C size sensor) The same as sigma's DC lenses. 
   
  XR : Extra Refractive Index Glass. 
   
  IF : Internal focus 
   
  ASL : Aspherical Glass used in the lens 
   
  LD : Low Dispersion Glass used in the lens 
   
  AD : Anomalous Dispersion - I got no idear...anyone??