This is more a discussion than an in-depth scientific experiment, but from time-to-time people come on here looking for a cheap-ish macro option. The suggestions are usually a subset of:
* A new m43 macro lens (often expensive ones from people who missed "cheap" )
* A used m43 macro lens
* An AF adapter for a macro lens in another mount
* An MF adapter for an old macro lens
* Extension tubes
* (Plus if I'm posting) A macro adaptor on the front of a lens as an option to consider
This all dates back to when I had a Canon Powershot G7 and wanted to do macro shots. You could add a LensMate adaptor to give filter threads and then choose an add-on option. I had a little pile of bits, some of which will feature shortly, although (spoiler) the LenMate adaptor won't be appearing again.
Now I have some nice macro options for FF, which I could adapt, but I only have a SpeedBooster-alike, which isn't great here (less focal length not being ideal). I could buy a Metabones Smart Adaptor but it's a lot of money, plus the AF isn't inspiring.
Anyway, I bought a Fotodiox 62-58mm step-down ring (see on for why, BTW annoying as I have a ton of step up/down rings, but not this one) and tried the three G7 combos on my GH5 with the Oly 45/1.2 (as it's very sharp and a reasonable macro lens focal length of 90mm equiv.)
I literally shot these just across the road from the Post Office where I had just collected the adaptor.
Processed in C1P as the light was varying a lot and I wanted to even it out somewhat. Sharpness, Clarity and Structure are identical for all shots.
Shot with the 45/1.2 at just about its Minimum Focusing Distance. Should be about 0.1x macro ratio. Click "Original Size" below to see at full res.
Canon 500D close-up lens, 58mm version with step-down ring (they make several filter sizes of the 500D). There is the suggestion you should use the 250D at 45mm, but I don't have one. More: https://cpn.canon-europe.com/content/education/infobank/lenses/close-up_lenses.do
Raynox DCR-250. Will fit lenses with filter threads 52-67mm. Note the effect of the thinner DoF as the magnification increases. More: http://www.raynox.co.jp/english/dcr/dcr250/indexdcr250eg.htm
With the DCR-250 attached to the front of the 500D (always the most fun/challenging option on the G7)
You do get AF, although I mixed it with MF as the GH5 doesn't always focus where I want on this type of subject (part of the reason for choosing the 45/1.2, as the MF is great).
I don't have m43 extension tube at all, let along ones with the electrical contacts passed-through as you'd really want. So not appearing here, sorry.
I think my conclusion is just using the Raynox on its own is the one to start off with for me. Looking at all the photos I took I had the highest hit-rate for what I felt were good images with it. (Although do take the front lens cap off before going out, as it really likes staying where it is, however good fingernails you have... hmm, maybe I should buy a 49mm lens cap for it.)
Thoughts?
BTW no promises someone else's results will be in any way similar, these are just what I got. I have 2008 versions of both adaptors, no idea if they are the same/better/worse now. (I suspect there's a good chance they are very similar, if not identical. I'm pretty sure Canon would have used a mkII designation for any notable changes, if only to get people to upgrade.)