Charisse Baldoria |
Eliminating Glare and Reflections I just got my first polarizer (linear). I noticed that, when I tried taking a picture of an aquarium, my flash unit's reflection appeared in many of the images. My polarizer's supposed to eliminate that, isn't it? Could it be just because the polarizer wasn't turned the right way, or could there be another reason it didn't work? I use a Canon F-1.
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John A. Lind |
Charisse, To eliminate the glare from the flash bouncing off of the aquarium glass back to the camera using polarizers, it requires two polarizers. The first is mounted on the lighting and polarizes the light from the flash. The other is on the lens. This is the method used when copying flat artwork and sometimes when photographing jewelry, silverware, or other shiny metal items for advertising. Sheet polarizers to do this with (for the lighting) are expensive, consequently they're typically found only in studios that do this type of work frequently. In addition, with a typical shoe mounted flash you have to "modeling light" to help adjust the polarizer on the lens. Two much less expensive and easier solutions are: (b) Leaving the flash on the camera and aiming it camera at the aquarium at an angle to the glass instead of "head on." This will also keep the flash reflection from bouncing straight back into the camera lens. -- John
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Charisse Baldoria |
Thanks, John, I really appreciate it. I see. So this type of polarizer isn't exactly glare/reflection-proof, is it? What exactly does it do then? Does it just lessen the glare compared to if there were no polarizer? Do u know if a circular polarizer is also usable by a fully manual cam like mine (Canon F-1). and would having that be much better?
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John A. Lind |
No, it's not. No polarizer is, circular or linear. First, about circular vs. linear: Next, about your specific glare problem: I will omit the finer details about how using two polarizers works (one on the studio light and one on the lens). The lights must still be at an angle, typically on light stands. The basic principle being used is polarizing all the light emitted by the strobe(s) before it's reflected from the artwork being copied. Explaining the finer details about exactly how and why all this works the way it does requires a pile of diagrams and a complete web page or two. A truly in-depth one easily occupies a chapter in a university Physics text in the section on light and optics. :-) -- John
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