How many layers in a stack?

The ease of use of the Cognisys Stackshot means it's very simple to dial up a large number of shots and read the paper while the deed is done. But this does impose penalties of processing time and of storage, amplified by the fact I'm now using a 36MP D800E.

Given the time taken to find a subject, set up, get the tripod just right etc etc, I didn't want to find blurred slices where focus had been missed; better 20 too many than 1 too few. So my recent offerings have been 80-100x stacks.

I thought I'd experiment to see just how many shots I really needed. I used the D800E with 105mm micro and PN-11 extension tube, which should give a maximum magnification of about 1.5:1 with appropriately narrow depth of field.

Aperture was 5.6 (after extension) to bring out any blurring. I did four stacks in all: 10x, 20x, 40x and 60x.

The aim was purely to assess depth of field and number of stacks required; just as well, as there will be no prizes for lighting or framing. Start position was the tip of the anther, finish position was the tip of the leaf at 2 o'clock.

The 10x Stack:

The 20x Stack:

The 40x Stack:

The 60x Stack:

To my great amazement, the 10x stack is all that is needed even at this high magnification. This is going to make life a lot easier.