I have been experimenting trying to find out how many images I need to stack to produce front-to-back sharpness in my small insect images with around f5.6. I concluded that only 7 of the series of 15 images I traditionally use contain any elements that are in focus for my very small subjects so I have been stacking just those frames and get much cleaner images without haloing. I have now set the stack number to 10 though will still only stack those frames with something in focus. With single shots, I tried high aperture number eg f18 or F22 (last 4 images) but the quality certainly falls off when fully closed down (last image). Lucky to have some great models for my experiments particularly the Tachina fera mating pair mating comfortably in a folded leaf and the Dung Fly exuding a droplet of water which is reflecting the spurge flowers it is resting on.
