Hi All

I was watching the latest episode from the "Underwater Photography Show" with Alex and Matt last night on Youtube. Alex just touched on using these types of filters for his underwater work at Lembeh. Is anyone else using these? can you help me understand the benefits of using these? Is there a specific filter manufacturer for underwater work? I do lots of shooting at the Blue Heron Bridge and it has a similar environment as Lembeh, so I'm looking for the benefits for me. Thanks

Hi Toque

I’m not sure that any specific manufacturer of ND filters makes them for underwater. Hoya filters are good and a reasonable price. The filters are pretty straightforward and underwater doesn’t make much, if any, difference.

Essentially they block light from entering the lens. So this means you can use a wider aperture at the same shutter speed, or reduce a high shutter speed - so keeping it inside the fastest sync speed - if in, say, bright, shallow water.

Thanks TimG. I dive plenty in shallow, sunny water. I'm planning on using it on the wet lens in front of my housing. I'm guessing that i should probably attach it underwater to get water in between the lens and filter.

Yep, for shallow, sunny water they can be helpful. HSS equipped strobes can be another way of achieving the similar results - although more expensively probably!

I'm not sure about the fitting. Usually ND filters screw directly on to the front of the lens and is therefore inside the housing/port combination and doesn't get wet. Hopefully!

If it is the case that the system you use has the filter in front of a wet lens - so effectively it is getting wet - my suggestion would be to install it before you enter the water and then "burp" it by unscrewing it and replacing to release air bubbles once you are at depth and settled. That way you know you have it, that it fits properly and won't disappear mysteriously from a BCD pocket as you descend.