Basket Star Revisited - With and Without Backscatter

In June of 2009 I had two posts, both had a picture of a basket star. The main reason I used it initially was to promote or talk about night diving. In this case, it is to continue my last post talking about lighting underwater and the issue of backscatter. We had weather issues on our recent dive trip to the Carribean which was the reason to offer an explanation.

The purpose of this post is to show an example of backscatter( particles in the water reflecting the strobe lighting back to the lens of the camera) and how trashy it makes the images. It is a tedious process cleaning the images but in most cases they can be cleaned to a useable state. Those examples can be found in the first two pictures. The third picture has been cleaned up to be much more visually appealing.

So far this post has been about capturing the image and post processing. Now I want to talk about the subject of the image, the basket star. Some of this was covered in that earlier 2009 post. The images in this post are successive, meaning there is an order. The first picture is the star as I first found it on the dark reef. After my modeling light was introduced to the star and the surrounding area it became a draw for many little organisms that are drawn to the light much like your porch light drawing moths and other things to your door. The star stretches itself out into the current to feed on those organisms that float past its tenicles. In the middle picture, beween the addition of my light and the immediate feeding of the star with those drawn organisms, the star begins to take on a narled looking state and reduces itself to a form you would normally see during the daylight hours. Its continued regression from its feeding state continues in the final picture. I hope it is interesting seeing the pictures and hearing about it, but it is even better in real time!

Paradise Reef Night Dive

Well, I've been told since I started shooting underwater, if you think your close, get closer. For those that are unfamiliar with underwater photography, a good strobe is a huge must have. The color spectrum is lost as you go deeper so to bring it back, you need to add white light. But water has particles generally not visible to the naked eye. As the light is added the risk of experiencing what is called "backscatter". This is where the particles reflect the light back to the lense creating pictures with white spots and requiring a great deal of cleaning with software to gain a useable image.
Another factor is the magnification of the water, where things appear 25% larger or closer than they really are.This causes one to think they are more intimate with their subject than they really are.
Putting everything together, getting closer reduces the particles between you and the subject and using a strobe up and away allows the light to be directed at an angle where the reflected light will be away from the lense, eliminating or reducing the backscatter.
Now, why am I telling all of this? Well, because at the time we were in the islands, we met Irene as a tropical storm, before becoming a hurricane. She dumped quite a lot of rain on the islands as she passed to the south of us and provided a great deal of run-off into the Caribbean reducing the visability for our diving for the week and added alot of extra particles to have to avoid. The images below were shot up close and personal on a night dive later in that week.