I was curious about the importance of a flash for a Sigma 105mm macro lens? I'd like to photograph some insects, and some of them at night! There's quite a few choices out there. The ring lights, and then there's the ring lights with the flashes on either side as well. Then there's some with the LED lights. I see that the ones with the LED lights have the option to keep the lights on steady. Would probably come in handy when it's dark outside. Thoughts?