>From: "John Petrush" <petrush@xxxxxxxxxxxxx>
>Subject: Re: [OM] Macrophotography of rocks and minerals
>
>...the T-10 with the cross polarization filter. With a guide number of
>only 10
>(meters @ ISO 100), it is not the most powerful flash around, but by
>polarizing the delivered light you have a lot of control over the final
>result with reflective objects.
It gets worse. The cross-polarizer turns it into a T-0.25! You lose 2-3
stops EACH DIRECTION THE LIGHT TRAVELS with the cross polarizer, so you
only have 1/4 to 1/9 the light to work with. It's probably useless for
anything over a foot or so.
I just bungled a shoot because I forgot to watch the auto-check light. I
was shooting with the T-10, cross-polarizer, and the 90/2. I was bracketing
for depth-of-field, but any shot taken at slower than f2 was too dark. This
was shooting from about 1/2 meter or so.
: Jan Steinman <mailto:jans@xxxxxxxxxxx>
: 19280 Rydman Court, West Linn, OR 97068-1331 USA
: +1.503.635.3229
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