Auto Focus Calibration

Misaligned Guides

As soon as I looked at the images on my computer, I knew something was wrong.  I was out of time and energy for that day so I held the question in my mind.  I thought about it while I slept.  I knew by the next morning that I must reshoot for all lenses.

I checked the instructions on the back of Lens Align and discovered that I must line of the guides.  I soon discovered that I must do so while looked through the camera.  Carol was unavailable so I walked back and forth a lot.

The guides are located in the square on the left and are labeled "A", "B", "C".  I used "B".  "A" was for when you use the large focusing target which I did not.  "C" is for macro lenses.  I assumed that the lens must be in macro focusing range.  I was not setting macro focusing in this exercise.

Aligned Guides

The trick is to align the holes in the device.  The back holes are surrounded with a target of red and white circles.  The front hole must be lined up with the back hole.  I did this by moving the device up, down, right or left.   Once this is accomplished you can read the scale on the right.  You look for the sharpest numbers and adjust the camera calibration accordingly.  The settings in the camera, no doubt, vary by camera.  My camera has a menu item for micro adjusting the auto focus.  Adjust one way if the sharp number is forward of zero and the other way if the sharp number is behind the zero.

I found that my non pro lens were pretty pathetic.  I had to adjust to the extreme of the scale and that was insufficient.  I have two pro lenses and they adjusted better.  They were on the scale.  

I embarked on the effort to improve my wildlife shots with my Sigma 50-500 mm lens.  It is a 1999 model and 15 years old.  I was disappointed with the results for it.  It showed itself not to be as sharp as I had hoped.  I would like the test the newer Sigma 150-500mm lens which had optical stabilization.  I have requested a rent to own loan lens for this purpose.  I think that I would be greatly temped to buy it if it showed itself to be sharper than my old 50-500mm.

The images above are 100% views of the shots made with the Sigma 105mm Macro.  It is what I consider to be my sharpest lens.  The bottom image not only shows the guides aligned properly but the scale after micro adjustment in the camera.

The top image used the same lens but was shot on the first day where I did not align the guides.  Non- alignment makes the readings from the scale irrelevant. 

 

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