Light Meter

[bluespotocto]

I have the nikon d300, but this a general question about wide angle. The camera has a built in light meter to use when you are on land. So you can adjust your f-stop and shutter speed accordingly. When shooting wide angle can I use this meter because most of the subjects will be to far away for my flashes to reach or does it not work underwater?

Thanks

 

[jdandvalerie]

I use the light meter all the time for wide angle shots on my slr. You would generally use wide angle to get as close to larger subjects as possible so the strobes can cover the full foreground of the scene (sharks, turtles, rays, tropicals etc...). If you are speaking specifically of wide angle shots of wrecks or larger scenes where you won't get strobe coverage, the light meter is still IMO the most integral part of the shot.

To give you an example, when I reach the depth I will be shooting, I take a meter off blue water and adjust my exposure accordingly to get the 'background' exposed how I want. The strobes will expose my foreground and I will manually adjust their power as needed. I use the light meter at depth not all that different than I do on land. You can experiment with metering and look at the results when you get home to see what ways work best for you. You just have to remember that if your composition changes, your settings will change. I had this happen today as I was taking a picture of a swimming Hawksbill turtle. I had metered my camera for the blue water in the turtle's background and was just using a touch of flash for the animal. The turtle then settled on a very sandy, light colored part of the reef and my next few shots were a bit overexposed as I adjusted to my 'backgound' no longer being blue water, but white sand. A good resource is: Wide-Angle Photography | Underwater Photography Guide.

Feel free to message or email me with questions.

 

[bluespotocto]

Thank you so much that answers my question. Now if I was going to take some pictures of a sharks and my strobes were going to be able to reach the subject should I still adjust to the light meter? Or should I just adjust my shutter speed accordingly to how much blue I want in the background and what will the f-stop just change the amount of light entering the camera?

 

[beautybelow]

What jdandvalerie gave you was a good description of what I was taught, called "metering the blue".

Usually done once on descent but as he noted that can end up being just a starting point depending on whether your subject ends up deep with darker water in the background or you end up shooting up at something with more sunlight in the background.

I always meter the blue with only the shutter speed leaving the f-stop on around 8. Then I use the f-stop to adjust the exposure of the strobes on whatever they hit.

This would be used for close focus wide angle.

Note that when metering the blue it should be the "middle blue" or the mid point between the bottom (or darkest part of the water if you are on a wall) and the surface taking into account where the sun is. Have a look around and quickly find the most neutral section of blue water and start there.

If you have a shot already set up like a sponge on a wall and know exactly where your background will be, then meter the middle blue and go minus 2 and that should be your exposure for the blue water.

 

[jdandvalerie]

Thank you so much that answers my question. Now if I was going to take some pictures of a sharks and my strobes were going to be able to reach the subject should I still adjust to the light meter? Or should I just adjust my shutter speed accordingly to how much blue I want in the background and what will the f-stop just change the amount of light entering the camera?

You should still use the light meter to get the appropriate color background. Generally speaking, the faster the shutter speed, the darker (bluer) the water will appear. You aperture should be adjusted depending on how much of the scene/animal you want in focus (depth of field). Again, generally speaking, your strobes probably have a maximum sync rate around 1/200th so your fastest strobe shutter speed will be limited by this. Use your ISO to give you more flexibility depending on the composition. For instance, when I dove today, I started at a base iso of 100 and found my blue background properly exposed was at 1/160th, f2.8. I wanted more depth of field than f2.8 so I bumped up my iso a few levels to allow for a smaller (higher number) aperture.

What I found works best for me is taking some practice shots at depth while using the light meter, then tweaking the exposure based on the subject. I change settings each time my subject or composition changes and will often bracket a scene a few exposures up and down if the opportunity presents to see the results. What looks good on the LCD screen isn't always what pops up full size. The beauty of digital is that it gives you the flexibility to take many shots and dial in your exposure just by pressing a few buttons.

Pick a stationary object first with a nice blue background and see what happens as you adjust your settings. But, I would trust your light meter to do most of the hard work and use the strobes as a means of splashing color on your subject just for a split second.