Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Next PZ lens test report: Tokina AF 50-135mm f/2.8 AT-X Pro DX
[quote name='Frank' timestamp='1342760032' post='19478']

Can somebody answer my question? Or, is my question too silly? <img src='<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='Smile' />


I don't think it's silly...

"So, what kind of problems with the lens can make the precise AF system of the camera think that the image is in focus while the image on the sensor plane is not in focus?"

You exclude the optical problems like focus shift and field curvature and ask about other potential problems arising from the lens itself. If we eliminate the optical elements, what remains is the built-in AF motor of the lens. AFAIK, the camera body does the math for PDAF / CDAF and -incase of a lens with AF motor- tells the lens motor to move the focusing elements based on these calculations. So in general I believe the body itself is mostly to blame (either the calculations or data stored for lenses in the internal tables or even maybe the parts like misaligned AF sensor / back mirror etc...). But maybe there's the possibility that the built-in AF motor in the lens does not listen to the data provided by the body.


Messages In This Thread
Next PZ lens test report: Tokina AF 50-135mm f/2.8 AT-X Pro DX - by PuxaVida - 07-20-2012, 07:46 AM

Forum Jump:

Users browsing this thread:
2 Guest(s)