Optix v5 AF-Confirm chip Focus Tuning Guide
Basic Knowledge
(1)On Canon EOS cameras the points of lens’ focusing ring at which focus assist indicator lights up are different when you approach the target by turning the ring from nearest distance side and infinity side. Very often you get more consistent result with focusing ring start from nearest focus distance mark so we always take this side as our reference of focus tuning.
(2)When handling focusing at big aperture size (e.g. f/1.4) the depth of field is so thin such that very
tiny further movement of the focusing ring after you get the indicator might induce a significant off-focus result. Hence it is good to practise well a technique of stop turning the focusing ring once the indicator shines.
Focus Tuning Operation
(1)Our Optix v5 AF-Confirm chip allows change of focus shift factor in the range 00-99. New chips are all initialized to the middle value of 50. If you find that value 50 is not giving you correct focus with you manual focus lens you may tune this factor according to your liking. For details on how to input this value please refer to the Optix v5 AF-Confirm Chip User Guide.
(2)You might need a focus test chart from Internet to start your focus tuning work. Start the test with value 50 and check if there is focus shift to nearer or farther side. Values 00-49 shift the actual focus point nearer to the camera while values 51-99 shift it farther away. The further away from 50 you choose the value the more intense is the shifting effect. So values 00 and 99 are the nearest shift and farthest shift respectively. Binary search (taking new value halfway on the good side) is a sensible way to get the correct value quick. If value 50 gives a focus nearer than expected, choose 75 on next try. On the other hand if it shows a farther than expected sharp point, try 25. Iterate this way until you get the ideal value. Every time you set the focus shift factor it becomes permanent.
