One of the most beautiful hikes I've done in the Pyrenees. The lakes reminded me a lot of the Enchantments in Washington State, another of my favorite hikes.
This is a moderate hike, a 9.5mile / 16kms loop with some 2,500 feet / 800m of elevation gain. Rocky terrain, it was also a bit slippery due to the rain of the day before.
Photography wise, there are plenty of opportunities. The hike starts through a dense forest with some very beautiful trees, and then opens up once the lakes start. You get incredible views of Midi d'Ossau, and there are other peaks as well.
As always in the mountains, it's all about the light. Conditions can change quickly, especially on partly cloudy days. If you find a composition you like, it might pay off to wait a little bit to see if the light improves.