Inspired by Toby (Marshall, a NG member), and saw several pics on flickr, I finelly found a leonon 50mm f/2 with a L39 mount on ebay Japan.
https://nikongear.net/revival/index.php?topic=8218.0With about 1 meter of closest working distance, I had to pull the lens with devices in order to get closer from these flowers. So I used the Z/M42 adapter plus a M42.M39 ring adapter, which is about 15mm between the lens and the Z6.
# Spring snowflake (Leucojum vernum)
# Blue bell (Hyacinthoides hispanica)
You can notice some bubbles, at f/2, having the shape of the diaphragm which is unusual : each blade has a convex curve !
Thanks for looking
Francis.