Fern by themselves should not be a problem around camellias. Autumn Ferns for example will probably look nice around camellias. I have some un-named varieties around several camellias right now.

However, I would look at the planting instructions for the ferns and find out how far they should be planted from other ferns. Then keep apart that distance from the camellias too. Some distance between plants improves the air flow between them and this in turn helps minimize fungal problems. After all, camellias are slow growers and you do not want the ferns to overwhelm the camellia bush to the point where you cannot see much of the bottom.