Saturday, December 9, 2017

Further refinements

A quick post to announce a few updates associated with my Focus Bar and Toggler scripts.

The Focus Bar now displays the sensor-limited focus area on the focus bar. Thus the cyan area is the focus field where the defocus blur is less than or equal to twice the sensor pixel size.

The near and far depths of field are the distances where the defocus blur satisfies the SQRT[MLCoC^2 - Diffraction^2].

The following shows what the FB looks like with the new sensor-limited info.

We see ML is reporting we are focused at 81cm and at this distance (at 12mm and F/6.4) the near and far DoFs are 56cm and 1.52cm respectively. This DoF information is shown twice in the above, because I haven't taken an image yet. Once an image is taken, and focus stacking is on, the DoF info at the bottom will show the DoFs of the last image taken, whilst the focus bar will show the live DoFs.

The (14), in the middle of the two DoFs at the bottom, shows the defocus blur criterion, in microns, based on the ML set Circle of Confusion you have set, ie adjusted for diffraction, assuming you have set it on (which you should have).

The [2] to the right of the near DoF at the top shows that you will need to take at least 2 focus brackets from this point to the hyperfocal. More if you wish to have good focus overlap.

To illustrate the power of this simple feedback, ie image to image focus overlap and the sensor limited zone, let's look at the next two screen captures, where we have moved focus from the first image (at 81cm) towards the macro end.

Note the bottom DoF now shows the DoFs of the last image taken, ie  56cm to 1.52cm. This information will remain as long as you don't take a new image.

The top images shows that although we have focus overlap (the magenta zone) this overlap is above the sensor limited zone. The new information that is provided after the near DoF (12) tells us that the blur at the overlap is 12 microns. Healthy, but not the highest quality you can achieve, which is the sensor limit, ie twice the pixel size.

In the lower screen capture we see that the overlap blur is reported as 9, ie (9) to the right of the near DoF on the focus bar.

Also we see that the number of brackets to the hyperfocal is 3, as we have moved away from the first image towards the macro end.

The Focus Bar script now saves the state it is in at camera shut down. So once you have configured the Focus Bar to way you like it, the camera will remember this.

As for the Toggler, I've created an alternative data arrangement in the script, which I hope makes it easier for others to tweak. Also, I've enhanced the UI so that Toggler shows you the state of the element you are about to toggler, eg on (green) or off (red).

As usual I welcome feedback.


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