A teleconverter can increase magnification on a macro lens, but it’s usually not the best value if your goal is more than 1:1. It adds extra optical elements, which can reduce image quality, and you still lose light.

Extension tubes or a bellows are generally the better option for higher macro magnification because they don’t add glass, so they avoid that particular image-quality penalty. However, any method of increasing magnification also reduces the effective aperture, so light loss is unavoidable.

At higher magnifications, apparent depth of field becomes very shallow, so macro shooters often stop down further and then need even more light. That’s why dedicated macro lighting—such as a ring light or small flash setup—is commonly used, especially for live subjects where long shutter speeds are a problem.

So: yes, a teleconverter works, but if you’re unhappy with the image-quality tradeoff, extension tubes are usually the cheaper and better route for going beyond 1:1.