Sunday, August 29, 2010

Auto White Balance -NO! …well, Maybe

Having lunch today at Whistling Willy’s (formerly Henry’s on the Hudson) in Cold Spring Harbor, I have come to realize that auto white balance is not necessarily the scary monster I had previously thought.

As a rule, I advise against AWB, (no reference to the ’70s R&B group that originated from Scotland) but I have to admit there are certain unidentifiable lighting conditions under which it solves a multitude of problems. Like, in dark, strangely lit pub sitting near an open window.

Normally when I’m indoors, I automatically think “incandescent” (the little lightbulb looking icon on digital cameras). And then I think, “wait…grab your Vivicap, and do a custom white balance”. But sometimes that just takes too long and I miss the shot. So, my new approach is to not discount the use of auto white balance when shooting under circumstances where there are multiple light sources.

An added benefit of this technique is that, in the event that I move onto a new light source, the results may not be optimal, but at least they won’t be as horrendous as they are when I forget to switch from custom to daylight, as is often the case when moving from say, the interior of a museum to the courtyard outdoors.

This might also be the perfect opportunity to talk about the little gadget I mentioned above, the Seculine Vivicap. It’s a center-pinch lens cap that doubles as a light diffuser for use with the custom white balance function.
Seculine Vivicap

I can use it to take both reflected light readings (light entering the camera which is reflected by the subject) or incident light readings (light before it falls on the subject). So, if I’m using say, a wide angle prime lens indoors and find it difficult to take a reading off an 18% gray card, I just point the camera at the light source and take a reading through the cap.

Let’s face it; I don’t really need this. I could just as easily carry a piece of folded-up paper in my bag, or, in a pinch, grab a white napkin off the table. But honestly, how much more convenient could this be than by having it attached to my camera lens as I take it out of the bag? I could have spend half as much, or three to four times as much. But at five dollars more than the price of a Nikon replacement lens cap, the price was right. And, like the more expensive models, the Vivicap also uses tiny prisms to gather the light from different angles.

I also considered the ExpoImaging ExpoDisk. It’s manufactured to much higher tolerances, and has the advantage of having an 18% light transmission, so it can also be used to take exposure readings. However, I question whether 18% is enough to take an accurate white balance reading. And at four times the price, I’m not going to find the answer any time soon.

Perhaps the Vivicap is also 18%, because I’ve used it to take exposure readings, and it seems to do a pretty good job. Using the exposure lock, I can take an incident light reading by pointing the camera at the light source, or I can point the camera right at the subject to take a reflected reading. In a darkened room with bright light coming through the window, the Vivicap’s reading averaged the light so interior details were clearly vivisible, while retaining enough darkness to capture the mood. I see a 52mm Vivicap in my future, which would be a nice addition to my Coolpix P5100 outfit.

Another handy gadget is the Lastolite EZ Balance Collapsible Light Balancing Disk. This device, similar to an automobile sunshade, has a white side and an 18% gray side, and because it can also double as a bounce card to add fill light to a subject, it’s also on my wish list. But, if I happen to find a nice, neutral, cheapo auto sun shade in the meantime, it’s mine.


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