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Sigma Service Center Experiences?

Discussion in 'Lens Matters' started by Legojon, Jan 8, 2020.

  1. Bazarchie

    Bazarchie Well-Known Member

    I have a dock which I use for firmware updates. I agree lenses should work fine out of the box, but it seems this is not always the case. I tried to micro some of my Canon lenses last year but it was a tedious process and I am not sure I was correct.

    Returning to Sigma should give you more comfort than doing it yourself.

    Buying a dock for future use is still a good idea.
     
  2. PeteRob

    PeteRob Well-Known Member

    To judge focus and depth of field you need to measure. Usually a plane target is set up at the required distance with a ruler running at a slight upward angle normal to the target and camera. Focus on the target and the ruler graduations that are sharp delineate the depth of field.

    The swan picture doesn’t look very sharp to me but I’m only looking on an iPad.
     
  3. GeoffR

    GeoffR Well-Known Member

    The D500 allows you to make adjustments to the focusing system, if you look in the menu you should see something like AF Fine tune (as it is called in the D4) . This may achieve what you want very quickly, I would read the manual first though.
     
  4. nimbus

    nimbus Well-Known Member

    What you must bear in mind about depth of field is that it is not exact, the word "acceptable" is used in the definition, in other words it will not be quite as crisp elsewhere as the point on which you have focused. Other factors come into play, even at the aperture you are quoted for, such as diffraction starting to appear after around probably f8, reducing the resolution, which on modern lenses is highest at surprisingly wide apertures. That is before even considering an assembly issue, such as decentering.
     

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