In reptile houses and aquariums (or aquaria if you prefer), the lighting is often low, or harsh and contrasty, which makes it difficult to get good photos. In this case, there was good lighting, plus I had a recently purchased a Manfrotto Lumimuse 6 led light on the camera (with the diffuser filter to make the light softer), which together made it easier for me to get a nice sharp photo of this beautiful iguana.