Some of these photos were taken with an expensive Sony macro lens and some were captured by a less expensive Tamron lens. There is not a huge difference between their qualities. It is not because Sony is over-priced. The main reason is: before the light can reach the camera sensor, the first piece of optics that the light had to travel through is the thick glass of the fish tank, which is not intended to be built for photography. If the glass is curved, the distortion will be even worse and no camera lens can overcome this type of obstacle. The only way to bypass the glass is to dive into the water. I am not a diver and thus this is the best I can do.