Fringeheads and Baby Seal Lobos Sunday April 6th dive

[limeyx]

Yes, it does, both manual and automatic. I'm not sure of the relationship, but the N1 setting let's in 1/4th of the light and the N2 setting let's thru 1/32nd of the light. So perhaps the N1 and N2 settings are the gross amount settings and the F stops for fine tuning?

The ND's are really meant for when you have used up the last (largest #) f-stop on your cam (or lens) and still have too much light.

Say your lens stops down to f/8 only, but you still have too much light (probably unlikely underwater), then you can enable ND1 to get an effective aperture of 2-stops less (which is equiv to 1/4 of the light)

I would always try to adjust the aperture first as then you dont have some filter in front of the lens, and if you then need an ND, add that in.

I usually leave aperture on auto when I shoot, but I am wondering if I need to start adjusting it per-shot. The 50W lights can really burn out the f/g but I dont know if it's better to use a smaller aperture or add diffusers (or maybe even both)

 

[DocWong]

Hi Doc,

I'd advise against using the ND controls in local waters except under very specific conditions. All they do is block light from entering the camera and with our visibility (ie lack of light) you never want that. I'd only use them if I was silhouetting a jellyfish against the sun in very shallow water. That might be necessary to avoid over-exposure shooting into the sun.

The aperture control should be sufficient to stop down enough to control the light against the sponges. Watch the zebra striping (unfortunately not viewable on the external monitor) to see what's getting blown out and dial down until there is only a minimum of striping on the display.

If the background looks to dark try shooting up rather than horizontally. Getting a balanced exposure with video is hard since the lights are on all the time rather than instantly like a flash so you can't use shutter speed to control the background. For local stuff I left the shutter fixed at 1/60th. Slower means the shutter is slower than the frame rate (well actually the field rate as every other line is 1/60th of a second). You can shoot with a faster shutter if necessary to reduce light but I never found a need locally. If you're in shallow water in the tropics you might want to shoot a faster shutter speed.

Clinton

Thanks! That clears up a lot for me!