Black background

[RDRINK25]

How to get one? Is this done is post editing? I am shooting a Canon T2I with 60mm and 2 Ys-D1's.

 

[James R]

While you can do it in post, of course, you don't have to.

It comes down to using a relatively fast shutter, tight aperture, and strobe angle/position.

This Wire Coral Goby was shot in the middle of the day @ 1/250, F22, ISO200 with my Nikon D7000 and 105mm VR macro lens. Strobes facing back towards the housing.

 

[TSandM]

One of my super photography instructors, JP Bresser, likes to say, "Aperture for foreground, shutter speed for background.". To get a black background, you have to use a fast shutter speed to minimize ambient light to the sensor. You make up for it with your strobe light on the foreground, so you can also use a fairly tight aperture, again to minimize total light through the lens. But it's surprising how big an aperture you can use if the shutter speed is fast, and still keep that black.

 

[Interceptor121]

In order to have a black background you need to shoot against the water column or use a snoot.
If you shoot against the reef or bottom no matter how fast your shutter speed is the strobe will light the whole frame
Example pedersen shrimp on reef shot 1/500 still can see the sand behind it
Pedersen Shrimp by Interceptor121, on Flickr
Quite large turtle (5 ft) shot against water column shot at 1/2000
Portrait by Interceptor121, on Flickr

What turns black is the water not the reef or sand

Addition: as the op has an SLR with a max sync speed probably around 1/320 you definitely need to shoot against the water as 1/320 is relatively slow

 

[James R]

Great point about the water column, I forgot to add that!

Even black sand, like what is common in Lembeh, wont be completely black.

 

[diver 85]

2 good articles about getting UW black background results........

(1)Black Backgrounds - a tutorial|Underwater Photography Guide

(2)--on strobe(s) position....Underwater Strobe Positions|Underwater Photography Guide