At extreme close up, depth of field is a problem. At true macro magnification it stops being a problem and becomes physics. A trichome head is bigger than the focus zone available to you, even at the smallest aperture you can reasonably shoot. You can get the front of it sharp, or the back, but not both. Not in a single frame.
This is why focus stacking exists.
what stacking does
You shoot the same composition multiple times, advancing focus a hair between each frame. Twenty, thirty, sometimes a hundred plus frames depending on how deep the subject is. Software merges them into a single image where every plane is sharp. The result is a trichome shot where the resin head, the stalk, the calyx behind it, and the pistil curling out of frame are all readable. Not just the front edge.
what you lose without it
Three things, in order of how much they matter.
Density. A non stacked macro shot of a frosted bud shows you maybe ten percent of the trichome layer in focus. The rest is creamy bokeh that reads as soft. That’s fine for art. It’s wrong for proving genetics. A buyer looking at trichome density wants to count heads, not enjoy a watercolor.
Structure. Trichome stalks have shape. Some are tall and clear, some are short and amber, some are bent over from late ripen. You can’t see structure if only the top millimeter is in focus. Stacking puts the whole architecture on screen.
Cultivar character. This is the one people don’t think about. Different strains have different trichome behavior. Some are uniform glassy heads. Some are clustered. Some have visible secondary trichomes between the main ones. Without stacking, all of this collapses into "frosty" or "not frosty," and you’ve thrown away the part that distinguishes good genetics from average.
the tradeoffs are real
Stacking takes time. A serious stack is several minutes per shot. Subject can’t move. Lighting has to be locked. You can’t stack a live plant in any wind. You can’t stack melting resin or anything else changing during the capture window.
It also doubles your post production. Stacking software is fast, but it’s another step. Every stack needs a quality check for halos and ghosting from any subtle movement between frames.
when not to stack
Live grow shots where you want context. Hero colas where the depth itself is the story. Concentrate shots where you specifically want one plane of dripping resin in focus and the rest dreamy. Editorial work where the soft falloff is doing the heavy lifting.
For everything else where the subject is "show me the quality of this flower," stacking isn’t optional. Without it you’re showing one plane of a three dimensional thing and calling it macro.