None! Don't! Do not do it.
Buy a true macro lens. You have good reason to. Of course I don't need good reasons to buy a new lens but you got one anyway. A macro lens is way better than using a non-macro lens with x-tubes.
I agree. There is no substitute for a true macro lens. However, many lenses have fairly short MFDs, and your camera has the resolution for some fairly deep crops. What you my really want is the software to stack multiple photos into a single image.
Depending upon the lens you want to use and what you want to photograph, you can probably make do without one. If you use macro extension tubes, forget about using autofocus.
You will almost certainly will [want] to use a tripod. It was the middle of winter, 18 inches of snow on the ground. I had just received my EF 16-35mm f/2.8L II USM in the mail from the Canon Refurbished Store. Shot with a 6D2.
This image was constructed from 10 separate shots, with each shot focusing on different slice of the coin, working from top to bottom. However, each of the individual shots was created for several identical shots which were "stacked" to reduce noise, much like you would a shot of the Milky Way. I really wanted to shoot the night sky, but the weather was not cooperating!
WOW, that is a great shot!
I was thinking of testing it out with my 24-70 ii lens.
I was simply curious what it's like to play with Macro, especially with the lockdown these days, can't go out so might as well try something new.
Thanks. Give it a go with the 24-70. I needed 10 separate shots to get the entire dime in focus, and PS did the rest.
I had cabin fever, too. I wanted to get outside shoot some stars, and then try my hand at image stacking to reduce noise. I wound pulling a dime out of my pocket, setting in on a paper plate, and taking several dozen shots of it. I bumped the tripod at the top of the dime, so there is a soft spot that did not align as well as it could have.