Built-in bounce card on SB-25?

I just got a used SB-25 and have been tinkering around with it. My question is: does anybody use the little pop-out white card that's built into the flashhead. I've heard some folks say that it can be used to bounce/diffuse the flash, but I can't say I quite understand how or to what effect. I'm mostly using this flash for outdoor fill in landscapes and such, and with my 105mm micro for close-ups, so any thoughts along such veins would be appreciated.

Not familiar with that unit specifically. If it's just a bounce card, it's of no use outdoors. Use of the bounce card indoors, however, will provide some fill light while most of the strobe's energy is directed at the ceiling and back down on your subject from above. If the card can be placed over the flash as diffusion, it would be useful for close subjects and spreading the light output when using wider lenses.

Outdoors the ceiling is a long way up, so bounce flash is useless unless you provide a large reflector or umbrella to bounce off of.

 

The bounce card on the SB24/25/26/28 is meant to be used when you are pointing the flash up at a ceiling between 90 degrees (straight up) and 75 degrees. The card intercepts light that would be going away from the subject (or would bounce off the ceiling and end up in front of the subject lighting the floor) and bounces it directly toward the subject. This provides a minimal amount of fill. Try a 3x5 index card and rubber band and you'll get more fill by intercepting more of the scatter.

 

The bounce card is also useful in some outdoor macro work.

As Mike has indicated, the card is intended for use when bouncing flash off a ceiling indoors. It redirects a small amount of light to fill in shadows under the eyes, nose, etc. (when I remember to pull the blasted thing out). In other words you get a sort of "double bounce" - a little light bounces off the card onto your subjects face, the rest bounces off the ceiling and lights your subject from above.<div></div>