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    Re: Daytime Venus Rising Dip Short
    From: Greg Rudzinski
    Date: 2012 May 8, 22:37 -0700

    Bill,

    I'm using a pair of Vivitar linears that are out of their frames and held together in front of the lens. The edges are marked with white out to indicate the maximum filtering orientation. At maximum the Sun is blue. The 10 MP DSLR Canon Rebel is a 2005 model which I consider a dinosaur. I use it in manual raw mode. Focus is kept at infinite. f22,ISO 100, 1/4000s to start then slow shutter from there until the Sun looks right. The 200mm is hand held. The images are then edited in iPhoto to enhance the contrast of the sunspots. I figure if a sunspot can look good then Venus transiting will also look good.

    Greg Rudzinski

    [NavList] Re: Daytime Venus Rising Dip Short
    From: Bill B
    Date: 09 May 2012 00:13
    On 5/3/2012 6:20 PM, Greg Rudzinski wrote:
    > I used an older 10 MP Canon Rebel with an adaptor to take a 1970's era
    > 200mm prime Pentax lens. The filter for the first photo had astronomy
    > mylar film over the lens (didn't work that good). The second image used
    > a pair of polarizers then the settings were at F22, ISO 100, and
    > 1/4000s. In iPhoto the image was cropped then adjusted for contrast,
    > exposure, etc.

    Were you using "old school" linear polarizing filters? (I am not clear
    if circular polarizing filters can be "crossed" to reduce light
    throughput.)

    There is a concern that linear filters can interfere with exposure and
    auto focus on digital cameras. Have you had experienced any exposure or
    focus problems?

    Bill B
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