Wednesday, June 28, 2017

Focus Bar update

A short post today just flagging the latest version of the focus bar (FOCUS on the right) as been released.

This version has a clearer 'user manual' in the text of the script and introduces an additional way to 'see' the defocus blur.

In the default DoF mode, where the two extremes of the focus bar show the near and far DoFs and the grey shading provides an impression of the focus field, I have now added in 10% distances.

Also, at these 10% distance points the focus bar shows an impression of the defocus blur diameter (ie the total blur less the diffraction effect), which will be at a maximum at the DoFs.

A black defocus blur means the blur is above the sensor limit, ie 2 x sensor pitch. A red defocus blur means the blur is below the sensor limit. Obviously at the point of focus the defocus blur becomes zero. The green dot, between the two DoFs, is, of course, the point of focus.

This version of the focus bar completely handles DoF, so switch off the DoF display in the ML DoF menu, but switch on the ML diffraction aware setting.

The DoF feedback at the bottom, ie above the ISO feedback, represents the near and far (defocus) DoF distances, with the defocus blur in the middle in microns, ie the total blur criterion less diffraction. The DoFs are zero because I haven't taken an image yet. Once an image is taken, these DoFs record the last image's DoFs, which is useful to know when focus bracketing. 

Here is what things now look like in the default DoF mode. BTW the red dots are simply from the cropmarks overlay I use, ie they have nothing to do with the focus bar.

As usual I welcome any feedback, especially ideas to make the focus bar more useful. BTW for those using the focus bar on an IR converted camera, you should change the diffraction frequency at line 150 in the script, eg from 550nm to, say, 850nm.

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