Photographing a candle flame will not normally damage your camera, sensor, or lens. A candle is nowhere near bright enough to harm the sensor through normal shooting.

The real risks are physical, not optical: getting close enough to the flame to heat the lens, burn something, or leave soot on the front element. Keep a sensible distance and you should be fine.

A longer lens can help because it lets you fill the frame without moving the camera close to the flame. Based on the community answer, your Tamron 70-300mm is a good option, especially if it has a close-focus or macro setting.

So yes, it’s a legitimate question, but in practice candle photography is generally safe for your equipment as long as you avoid excessive proximity to the fire.