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easyrider003
01-29-2008, 20:37
I bought the canon underwater housing for the a570is. It is cracked so I am having to send it back to the company. Anyways, it came with a diffuser or whatever that snaps to the front of the housing in front of the flash. What exactly is that diffuser used for?

Puffer Fish
01-29-2008, 20:51
I bought the canon underwater housing for the a570is. It is cracked so I am having to send it back to the company. Anyways, it came with a diffuser or whatever that snaps to the front of the housing in front of the flash. What exactly is that diffuser used for?

You will see diffusers used on almost every P&S housing, and most strobes.

There are two reasons that I am aware of:

1. This is the biggest - due to the refractive index of water and air, the angle of the flash is reduced, so to get wider coverage, they uses a diffuser.

2. Spreading the beam out, also helps a bit with the degree of back scatter. The worst place for a flash in this regard, is near the lens, but that is exactly where the strobe is. reducing the intensity of the flash and spreading it out, means you may get back scatter, but each spot will be less intense.

easyrider003
01-29-2008, 21:15
O ok. Thanks for the help. I havent used it yet, of course, but I am gonna use it for the first time at ABWA. Maybe I will have enough time to fool around the camera and get used to it underwater before I head to the Bahamas in May

Puffer Fish
01-30-2008, 09:57
O ok. Thanks for the help. I havent used it yet, of course, but I am gonna use it for the first time at ABWA. Maybe I will have enough time to fool around the camera and get used to it underwater before I head to the Bahamas in May
If you get an external strobe (which you really should, by the way), that deffuser can now be used to make the light block / fiber optic holder. Mine has black plastic on the back and a 7mm hole for the fiber optic cable to plug in...