Quick question about MWB?

[BDSC]

When I was in Bonaire a few weeks ago I was using one of those white writing tablets/slates as a WB reference. MY question is this:

When you do a MWB, should you hold the slate close enough to the lens to fill up the screen with the white from the slate or should you hold it a little farther back from the lens and then zoom in to fill the screen with white? Or does that even matter at all?

Thanks!

BDSC

 

[Drewski]

Hi BDSC:

Yes, it does matter.

I'd suggest a few things. First, in clearer water, with good natural light, I've had good results with a mounted slate about 12 inches from my port. This gives enough space for the slate to reflect the light. I'd try and keep the sun above and behind me when white balancing. Zooming in to get 100% of frame fill is also important. An alternative in bright clear water is to simply point the camera at the sun, zoom in and white balance using this as a source.

If you are using video lights, a close mounted slate will NOT work. In fact, you will probably get a red shift and be frustrated. The best thing to do in this case is to use a separated slate that someone can hold, or that you can set on structure or the bottom. I like between 3 and 5 ft of offset for the slate. I set my light ams as I need for the dive, move in and zoom on the slate with my video lights on, then MWB. You should see no red tinge on the edges of the lit area or in any of the objects illuminated.

Occasionally, I play with lighting techniques during a dive to produce certain effects. Here's a recent video from a training dive. Notice the illumination of the object at 00:51 in the video. I did a MWB with a red shift prior to shooting the clip to create the effect:

[vimeo]10196341[/vimeo]

Hope this helps...

Andy