The Deceiver

I went over to Ennerdale (Bleach Green) for a wander about in the woodland by the river. I was hedging my bets - mushrooms, squirrels or birds. 
Mushrooms won the day,  I couldn't find any for a while then I spotted a couple of these , I think they are called Deceiver Mushrooms, apparently the are edible..
When I got down to mushroom level I realised there were loads.  I tried my hand using the 6700s focus stack mode.
I focused on the closest and then set it off and away it went and took about 20 shots. When I looked at them they individually all seemed pretty sharp, I stacked and merged them in photoshop but success was partial, you can see the closest group are not sharp even though there are individual images which are sharp for this group. I left them in the composition because I like the procession of them up and around to the tree hollow.
More practice required, I'll try some smaller apertures which should produce fewer images to stack and see if that makes any difference.
Would be interested to know if anyone else's experience with focus stacking.?