I tested the AstrHori 25mm f/2.8 2–5x Ultra Macro as a dedicated extreme close-up lens, and it genuinely feels like a microscope once you hit 5x. It’s fully manual, built all out of metal, and the image quality I got was razor sharp even around f/4—just be ready to bring a lot of light.
Pros
+2x to 5x magnification for extreme detail
+Razor-sharp results around f/4
+All-metal build quality
+No visible vignetting on full-frame in my shots
+Minimal chromatic aberration once stopped down
Cons
-Fully manual focus (not for everyone)
-Very hungry for light, especially at higher magnification
-Extremely shallow depth of field makes shooting tricky
-Not practical for portraits or general photography due to close working distance