Translucent tadpoles against a white background. HELP!

[kyle_opitz]

I need to photograph tiny translucent tadpoles for my sister�s science class.

I�ve used my auto extension tubes on my Minolta X700 before and achieved nice

results. I couldn�t get enough natural light next to a window, and I didn�t

want to cook the little guys with continuous studio lights, so I am going to try

using a couple of dedicated flashes (I hope this doesn�t cause them to go

blind!) The problem I have with the tadpoles is that I am shooting them against

a white background. I�m worried that my camera will miss-meter the scene

because only the eyes and the internal organs of these little guys will be dark

against the bright white background. What can I do to make sure this doesn�t

happen? Does it even matter what color the background is with such a small DOF?

Any tips on how to set up the flashes to reduce glare and bring out detail? Any

help would be greatly appreciated!<div></div>

[Ed_Ingold]

Try lighting them with a flash from the top against a dark background. Alternately, try lighting them from behind against a light background, pointing the flash toward the background. Their outline and internal structure should be plainly visible. You could start with an incident flash reading, and bracket from there. The camera should be in manual mode - TTL is useless in this situation.

[mark u]

"The camera should be in manual mode". Well, yes, you need to ensure that you choose the aperture for DOF and a shutter speed that's X sync or slower. But I think Edward meant that you may need to set the flash power manually too. That way you can have consistent control over lighting. You should start with simple guide number calculations to estimate appropriate flash to subject distances, but you may need to reduce effective flash power from the simple calculation at close distances. You can do that by increasing the flash to subject distance, or using one or two layers of handkerchief over the flash as a diffuser (hold in place with an elastic band). Bracket your effective flash exposures. Angle the flashes to avoid reflections off the glass of the aquarium and use a hood or snoot the flash so there is no direct path from the flash to the front element of the lens.

[Ed_Ingold]

Yeah, Mark, I thought that was obvious.

[kyle_opitz]

Haha Thanks guys, i'll give it a shot. I'm lacking a flash meter so i guess i'll be winging it and bracketing. Thanks for the tips.

[timsumma]

You will find that this may be way to much for you but it will knock people�s socks off! Get two polarizing filters, one for your camera lens and another that is a junker. The junker will go over the small flash at the read of the tank and the other over your camera lens. You will set the two filters in opposition to one another. WHAT!? Hold one up and with the other turn one until they both go black, mark this on a piece of tape attached to both of the filters. Place the rear filter between the small flash and the rear of the tank, set it so you won�t see it in the image. Now place the other polarizer over your lens and orent the filter so that it is back to opposition to the rear filter. When you make images the little beasties will show in all their slender with the fines detail of color and structure while the water will be black or a slight coloring. If you want an explanation of what is up the book The Dancing Wu Ly Masters, look for an explanation of Bell�s Theorem.