Yes, a macro lens with an SLR is a must. I am an old film photog from the old days.
With an SLR, either a macro lens or an extension tube is needed. An extension tube pulls the lens away from the focal plane, adding to its focus range. The lens will not focus except at very close to the lens. There is a loss of light gathering as the speed drops since the aperture value is only valid at infinity focus. Since the apeture says the same and the focal length increases, the f ratio (focal length to apeture) increases.
When the focal length increases, depth of field decreases, making focus critical. This is why you need an SLR. Focus.
Then we have depth of field. This also decreases with increasing focal length...and so does camera shake.
I've done some impressive stuff with just a 55 f 2.8 Micro Nikor and a PN-11 extension tube, shooting Ecktachrome 50. This makes greater than lifesize images...photograph a dime and the image on the slide is larger than a dime. Blow that up on a projector and 500x magnification is clearly available. But you better have a powerful flash and bright lights.