I've been interested in photographing bees recently. Rather than buy a macro lens, I spent $32 on a 10mm and 16mm Meike extension tube. Photos are with an A9II + Sigma 35mm f/2, which normally offers a 0.18x magnification. All four are taken as close as the lens will focus. I'm very happy with image quality, especially given that this lens doesn't have a super flat focal plane at its minimum focal distance.
For anyone who tries an extension tube for their first time: you won't be able to focus very far in the distance (beyond about 1 foot in my case). Be ready to get up close and personal.
Like a magnifier that goes in front of the lens? I'll have to do some googling, thanks!
Yep, there can be a good amount of chromatic aberration especially on the thicker ones, but sometimes that looks cool.