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I have macro lens, extension tubes for Sigma, Minolta A mount, and bellows for Pentax M42 and Konica AR mount. Of the three I find a a true macro lens easiest to use in the field followed by a set of extension tubes, then a bellows. I don't recall ever seeing a bellows for an AF body, but I have used my M42 bellows and adaptor with a Sigma Sa 7 with good results. What mount and lens do you have on hand?
30years ago I was on a budget: cheap reverse adapter + a stepup ring + whatever Minolta lens I had
After switching to Canon I used the EF100 2.8 macro: great lens but extra weight in my bag and not so easy beyond 1:1
I sold it an bought me a reverse ring for EF mount and a set macro extenders
Together with some old manual prime f2.8 lenses I picked up for less then 20€
later on I did some research and bought the kit lens EFS18-55 IS for 25€: great for reverse macro from 1:1 to 5:1 !!!
at the moment I use different setups depending on the subject
as Canon users, we are blessed with the quit cheap Meike MK-C-UP for reverse handheld autofocus and aperture controle (AF usefull depending on camera, lens and available light)
with or without extension tubes between this adapter and the camera.
I prefer internal focusing fast prime lenses because AF will work better and the Meike cable will thank you
From 0: to 0.3:1 ; EF100-400 II for the distance on bigger insects
From 0.8 to 8.3:1 ; EF24-85USM reversed and frontlens removed
From 1.1:1 to 5:1 ; EF50 1.8STM reversed (for 5x you need 20cm extention!)
From 3.5:1 to 7:1 ; with EF24 2.8 IS reversed when distance is not important (AF works!!!)
and a self made very thin extention tube on the EFS10-22 not reversed for wideangle "macro" ; 0 to 0.55:1
experimenting at the moment with microscope objectives and tube lens
If you want to go there too search for allanwallsphotography articles and others
IMO "the lesser glass the better" (no extenders, filter, second lens, ...)