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    Help with AF micro adjustment

    Following The Black fox post on AF micro adjustment, i thought i will have a go and see if my new (old) 300mm f2.8 non IS need any adjustment

    Due to the poor weather, i was forced to do it indoor and i want to have the same light and hence went for flash on manual. So the setting was,

    1. Camera on tripod spot metering and single centre point focus, single shot one shot manual at 1/125, f8, ISO 100, subject was 12 foot away and the flash was wireless triggered with diffuser on at about a feet away zoomed to 105mm at full power.

    I have posed some 2 different picture after narrowing down from several picture and lots of time looking and starring at them by myself and my son.

    I obviously seen some difference between 0 and -20, +20 but cannot make much difference on between 0 and -20.

    My question is do you see any diffence on these two picture on 0 adjustment and -20 adjustment if not is it so on these type of lenses.

    All the images are straight out of camera in raw just converted into jpeg with no processing.

    1. 0 AF adjustment


    2. -20 AF adjustment


    3. 0 AF adjustment


    4. -20 AF adjustment


    Thanks
    Raj
    Raj
    Flickr

    #2
    Re: Help with AF micro adjustment

    Sorry about the smaller link, not sure why this is from Photobucket but if you click on the link it should take you to the full size image.
    Raj
    Flickr

    Comment


      #3
      Re: Help with AF micro adjustment

      Hi Raj - you need to shoot with the lens wide open i.e. f2.8 - there is too much DoF at f8 - Regards John

      Comment


        #4
        Re: Help with AF micro adjustment

        Thanks John, i will do it, the reason i choose f8 is, most of the time it is what i will be using it. My other question is is 12 ft too short for this kind of adjustment?
        Raj
        Flickr

        Comment


          #5
          Re: Help with AF micro adjustment

          I believe Canon recommend 50x the focal length - so 15m - Regards John

          Comment


            #6
            Re: Help with AF micro adjustment

            Thanks John i will try again tomorrow (outdoor) when the weather is better and brighter.
            Raj
            Flickr

            Comment


              #7
              Re: Help with AF micro adjustment

              I used to micro adjust at short range but I found that while close shots were perfect ,distant shots tended to be O.O.F ,my recent method is this ,I used a bus stop a hundred or so metres down the road as the target ,due to the fact it's got a bus drawing ,words and a grid on it .

              I set the camera on the tripod ,lens wide open ,single shot mode ,then went through from -20 to plus twenty in five point sections ,nine shots in total ,put them on computer and blew up the sign to 100 percent pick the sharpest and then did another 7 shots either side of the best one .its a painstaking job and you must remember to re.set for each shot it has seemed to work so far and I basically just chose a target at what I considered to be normal working distance ,whether this turns out to be a wise choice still needs finalising time permitting .

              I chose the bus stop sign as it's so similar to a eye test chart btw .might be worth your re.doing this to get it right

              P.s the lens MUST be wide open for correct micro adjust

              this it the target i used .
              664O6247 by blackfox wildlife and nature imaging, on Flickr

              and heres one from this afternoon ,my main fear was i might have altered the close focus ability ,this was outside my kitchen door today poor light and i forgot to re-set iso so 400mm f5.6 hand held at 1/200th sec ,pleased am i with the results yoda .
              NO FEAR ! by blackfox wildlife and nature imaging, on Flickr
              Last edited by the black fox; 19-07-2014, 19:48.

              Comment


                #8
                Re: Help with AF micro adjustment

                Thanks Jeff, I will be pleased with that short. I will have a go tomorrow and see. Now i need to find the bus stop with the sign on......

                I have been reading about it for some time now and thinking of borrowing my son ruler and setting it up at 45degree outdoor and see if i can do it that way in my garden.
                Raj
                Flickr

                Comment


                  #9
                  Re: Help with AF micro adjustment

                  I have the proper angled tester for doing the MA but your limited on range as I said ,from personal experience you need a compromise between dead sharp close up and dead sharp at distance ,the latter being what prompted me to try it out again .as I was getting blurred focus at distance .luckily I have two cameras 1d3 and 60d plus two 400mm lenses canon and sigma to swop around and establish whether there's a problem or not initially

                  Comment


                    #10
                    Help with AF micro adjustment

                    Thank you for the tips and help, after my diy technique of using line pegs as subject placed apart in few cm distance and then fine tuning with eos magazing on the cloth line, nailed it. Now my 300mm is spot on at 2.8 at both near and far distance. As i was predominantly using at f8 i never noticed this as a problem and only when i took it for test after seing Jeff post i realised the problem. Now that i got all set up,ran this with other newer lenses and none of them needed any adjustment apart from this older 300mm f2.8, non IS.
                    Raj
                    Flickr

                    Comment


                      #11
                      Re: Help with AF micro adjustment

                      glad to have been of help

                      Comment

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