Focus Merge Failure

[MikeFromMesa]

I have been testing the functionality on a new Olympus E-M1 Mk II and part of that is the automatic creation of a set of focus merge photos. The camera automatically changes the focus for a series of shots and does not stop until nothing is in focus. This works well, but using the set to create a Focus Merge image in APB gave me this:

 

 

I added all of the images from the set and clearly that caused this OOF issue with the assembled image. Picking fewer images fixed the issue but why would adding extra images where, presumably, the background items are in focus, cause this problem? What are the guidlines for adding images to a Focus Set? Does APB go astray if some of the images are OOF? Or if some have the main object of the image OOF, even if the background is in focus?

[billtils]

Mike

 

Some of my more successful focus merge results have come from 5 or fewer images.  Did you try this with a range that goes from one just in focus at the front of the object of interest to one just in focus at the rear of the target, with one in the middle and one between the middle and the two extremes?.   It may be that AP's algorithm needs something to define the start and end?

 

 

Bill

[MikeFromMesa]

Bill,

I shot the images at a reasonably high aperture so it really only took 2 or 3 images to cover the entire range of the flower. APB was successful with those images but lost its way with the entire set.

 

I do not know what algorithm they use for the blending but I assumed it involves sharpness of the contrast (and hence the focus) to determine which parts of the image are OK to use and which are not. I have written enough software to not be too critical of someone's algorithm because it is often the case that the the easiest way to speed and success under one set of circumstances leads to failure in another, and that may well be the case here. Still, I thought it was worth mentioning online so the moderators could report the state to the developers.

 

Mike