I've recently started exploring with focus stacking. I have a macro slider rail with metric measurements that allow me to precisely adjust the camera distance to the subject. Depending on the depth of field and the lense being used, I will usually take photos between 2mm and 5mm apart. I'll end up with about 15 photos that I will then load into Photoshop CC that aligns the photos in the stack, picks out the portions in focus, and combines it into a single image.
When it works, it works great! However, sometimes Photoshop doesn't pick out portions that were in focus, and leaves the photo with random bits that were blurred. Here's an example from a session this morning:
There's a random bulb on the right that is out of focus, where every other one looks fine. Also, just to the right of the bulbs in the middle, the flower pedal starts out in focus, before suddenly going out of focus. Looking through my stack of photos, I had shots where these portions were all in perfect focus.
Is there a way I can fine tune the stacking process, giving photoshop hints of where it went wrong and correct them? I've read lots of tutorials on this topic, but none of them even hint that Photoshop could make a mistake or how to correct it. Anyone here with advice?