# REIKAN FOCAL Aperture Sharpness test results interpretation



## smi (Oct 11, 2013)

The latest version of FOCAL Pro includes an aperture sharpness test. I used it with for my 1DX and both 50 1.2 and 85 1.2. I run these tests with different AF micro focus adjustment settings. Can we assume that the micro adjustment settings with the highest numbers graphs, are the best ones? In most cases these settings did not agree with the results of the FOCAL auto calibration method.

Thank you...


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## Mt Spokane Photography (Oct 11, 2013)

It would help to give us your data or post the resulting curve.

The result of the aperture sharpness test is a plot that shows the relative sharpness at different apertures. It does not change AFMA, just aperture. The shape of the curve should not be different with AFMA changes.

I'd look at the shape of the curve, it should be fairly smooth with the sharpest (highest point on curve) occurring when the lens is stopped down by 2-3 stops, the exact amount depends on the lens model and is fixed due to the design of the lens. All 50mm f/1.2 lenses should give pretty much the same results if greatly different, there is a problem.

If the highest point on the curve is f/11, for example, your lens is defective.


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## smi (Oct 11, 2013)

I am attaching the two graphs. The 'smoother' graph with the highest numbers at the largest apertures is the one with 0 microadjustment.


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## smi (Oct 11, 2013)

I am also attaching two more examples with my 50 1.3 at 0 and +3 microadjustment


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## Mt Spokane Photography (Oct 12, 2013)

As you can see, the high point on both charts falls at the same aperture setting. A better AFMA means more sharpness, but the sharpest aperture stays the same.
f/2.5 for the 85mm lens and f/2.0 for the 50mm.
Its possible that a very well lit and careful test might change things, but not much if any.

You should see your sharpest images at those apertures for the distance you used to test the lens. Distances might change things as well.


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## smi (Oct 12, 2013)

Can i assume then that both lenses are sharpest with MFA of 0? The auto Focal test for the 85, shows that it needs a +4 adjustment, which is not what the above graph show...


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