The two photos below have generated a lot of questions. They are both single in camera photos on film using natural light. They were not put together from two different shots in photoshop or otherwise manipulated.
Nikon F100 Camera
17-35mm f2.8 Nikkor Lens
Subal Split Diopter + 3/ND2 Filter (bullfrog only)
Subal Underwater Housing
Fuji Velvia Film
Bullfrog (Rana catesbeiana) on Lily Pad
The bullfrog photo cannot be accomplished in camera without using the split filter. Simply put, water magnifies, and a diopter is needed for the focus to be equal above and below the water’s surface. Since the light above the surface is usually brighter than below, the top half of the split needs darkening to balance the lighting across the entire image. This filter accomplishes that as well. As a side note, the diopter/neutral density optics come in different graduations of power for use in different situations.
Southern Stingray (Dasyatis americana) and Boat
The stingray photo, on the other hand, was taken without this filter because the ray and boat are two different subjects, not connected above and below the water. The distance between the ray and boat were about the same, the water magnified the scene, making it appear as though the ray was much closer. I also increased the depth of field by using a smaller aperture. The shallow, crystal clear water and white sand of Grand Cayman negated the need for a graduated split neutral density filter. Lighting above and below the water’s surface were about equal.
Other lessons learned in taking these photos: When a large bullfrog eats another, smaller frog, he tends to be too full to hop out of the frame, and stingrays have no problem making eye contact with the camera.