After that bug I thought let's put the conchyl on the balcony and see what happens. I think my DoF is less than adequate here. Any comments would be very welcome.
I see what you mean. I guess that the back part of the shell (the contour against the sky) is also overexposed which makes the loss of focus even worse.
I think your focus could be slightly further back, to include the whole shell, Nick! Otherwise I like this one the best for the composition and uncluttered background. Dave.