Thank you.
I was under the impression ring flashes are a great plus for macro photography? I just bought a RF 100mm. I was thinking I would need a ring flash. What would you recommend for macro photos?
The idea of a ring flash is attractive, but hardly any macro shooters use them because of the issues mentioned. It might still be OK for you depending on your needs and subjects.
Most macro shooters including me use diffused flash. There are MANY ways of doing this, and you will find hundreds of arrangements online.
For shooting bugs hand-held, I use a regular speedlite mounted in the camera hot shoe firing into a diffuser. The diffuser can be any translucent plastic material. My favorite material is plastic stationery material sold as a portfolio or as dividers for 3-ring binders, available from Staples for little cost. Some folks use packing material. There are good diffusion sheets in old monitors and TVs too.
Don't put the diffuser right on the flash head. It needs to be some distance away to give the light from the flash an opportunity to spread. I mount mine on the front of the lens. You can use an elastic for this.
A lot of the light can be lost because the flash usually can't be aimed down enough, but a snoot lined with reflective material (aluminum foil) can help recover most of that light. Pic below.
In the macro studio, my setup is different, because now I can arrange little reflectors and diffusers with way more control. Paper works well for this. Usually I use continuous sources (LED lights) instead of flash. So the setup depends on what and how you are shooting.
Here is a rig I put together a few years ago. My current bug rig is still about the same.
It helps to have a fairly powerful speedlite, because then you can turn the power down to 1/4 or 1/8, and that shortens the flash duration. That helps to freeze motion. You can shoot manual or TTL - either works, but sometimes one will be preferred over the other.