Sharness -AND- Glow
But what if we want a sharp subject surrounded by a wider, but more subtle glow? Put another way, what if we want to increase the radius of the glow while reducing the density of the glow? Can we do that? Well, yes!
Since we are looking to control the "mix" of light passing through the center and the edge of our lens, we will need a more complex aperture that blocks some of the light passing through the outer part of the lens.
There are many possibilities for such an aperture. We'll start by borrowing from a classic commercial soft focus lens: the Rodenstock Imagon.
This photo shows my attempt at replicating the Imagon. The lens is the same 75 mm achromat used for the previous examples. It was purchased from Surplus Shed for under $10 and mounted in recycled filter rings for easy attachment to my bellows. The paper aperture rings are inserted in between the lens and the bellows.
This was the setup used for the previous two photos of the yellow dandelions. For the sake of discussion, I'll refer to the disks as disk 1 through 4 starting from the left. The first dandelion image (page 8) was taken without any disk and the second image (page 9) was taken with disk #1.