Recently, I've developed a taste for macro photography and have a question concerning the light.
I'm currently shooting with a Sigma 105mm Macro + Kenko extension tubes. I have an older model of the Sigma lens, without internal focusing, so in order to achieve 1:1 magnification, the lens has to extend to the maximum. This, combined with extension tubes, makes this lens very long. I'm also using a Nikon SB-900 speedlight but I never shoot directly at my subject. I always tilt the speedlight (30 to 40 degrees) and use the bounce card to diffuse the light. In order for the light to reach the front of my lens, I almost always have shoot full power. This is quite problematic as the speedlight takes some time to recharge and my batteries usually last approximately 2 hours.
I want to make a home-made snoot in order to channel the light, which will save the batteries and I won't have to shoot full power. I don't want to spend money on expensive flash benders so I decided to use a thick piece of black cardboard that I can cut into whichever shape I want.
My question is: Do I have to cover the interior of the snoot with tin foil or white paper?
I noticed that most soft boxes, snoots and flash benders have interiors covered with either shiny or white surfaces in order to diffuse or reflect light. I don't want to diffuse the light but channel it. I can attach a diffuser to the end of my snoot to diffuse the light. Do you think that thick black cardboard is enough? After all, the black cardboard surface will channel the light instead of absorbing it?
Thanks you and I'm looking forward to reading your comments.