These are sprouting in fields and grass roadside verges here and in other parts of the UK just now. The plant is Cardamine pratensis, or more commonly, the Cuckoo flower because it appears about the same time as the arrival of the migrant Cuckoo bird. In some parts of Scotland it is also called the May flower and associated with the saying "Ne'er cast a cloot 'til the May be oot" which translates as "keep wearing your winter clothing until the Mayflower appears" (there is a more common version that goes " ... May be ...", referring to the Month).
The first image was taken unstacked with the 24-85mm lens at its maximum zoom, The flowers are approximately 8mm across.
Unfortunately the flower did not last long in the water, and the second image is of a dried and pressed head from the sprig, taken with the 50mm prime + 36mm tube, focused via tethering in CaptureOne, and processed in Zerene.
I did try a single petal with a different tube combo to get maximum magnification, but I need a bit more practice at that level ...