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AF Micro Adjustment

Focussing Concerns - Check Your Canon AF Micro Adjustment Settings
As we have reported previously here at Cameracal undertaking the number of calibrations that we do, we tend to come across a number of different problems, some on a regular basis some not.
The problem we are about to describe though has only been seen on perhaps 5 -10 separate occasions but nevertheless can explain some problems customers have experienced. Most customers when they contact us express their concern that their
images are not as sharp as they had hoped. Those who have investigated this further mention that the camera and lens combination seem to either exhibit front or back focusing problems. We normally run through the list of checks with them as we do with every customer, these being:

Front / Back Focussing Check List

  • Are you choosing the focus point manually and if so, did you place this over the intended shutter speed?
  • Was the chosen shutter speed sufficient to prevent camera shake for the chosen lens /genre, thus adhering to the minimum shutter speed rule.
  • If using an image stabilised lens was the camera positioned on a tripod and a cable release / self-timer used?
  • Has the equipment used been knocked or dropped?
  • Does the lens in question have a filter attached and if so, what is the make / model of said filter?
  • Have any of the in camera micro adjustment values been altered for said lens.
If all of the above can be answered, then this normally indicates there is either a lens optic or camera AF sensor displacement problem or both for which calibration can normally correct. Another check that we are to include in the list is as follows and is the
reason for this post. When attaching a lens to a Canon EOS body a micro adjustment value can sometimes be applied to ALL LENSES.....

Canon AF Micro Adjustment Applied To All Lenses

YES you did read right..
The first time we saw this, we assumed this had been an input by the customer in their attempts to correct their focus errors. The second, third and consequently all other examples I contacted the customer to ask if they had attempted to calibrate the camera / lens combo themselves and perhaps made an error. In all examples the customers reported they had not and in most cases
the customer was unaware of how to even apply calibration settings. Also in each example, the camera exhibited the same mirco adjustment value -8 on all lenses which meant that every lens used with the camera would effectively be FRONT focusing by 8 micro values. We contacted our colleagues at Reikan to report the problem and they had never heard of the problem and could not shed light on why the camera in question would default to this auto correction.
Our colleagues at Canon had not come across this either. In fact colleagues here at Cameracal dismissed this themselves until they came across the same problem. Included are three images as testimony that this problem does sometimes occur (note images were taken on three separate dates).
Canon AF Micro Adjustment Canon AF Micro Adjustment Canon AF Micro Adjustment
So in essence, if you are experiencing focus issues, please refer to the check list above and also check for this phenomena. The AF micro adjustment value can be found in the AF section of the camera. Please refer to your instruction book if required.