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Vio1
01-10-2007, 07:56 AM
Hi, i recently purchased a Canon S3 IS and got a lensmate 52mm adapter for it. I also purchased the Hoyo liner polarizer and a uv filter. My question is regarding the Polarizer. Unlike the uv filter, the polarizer has two rings which when screwed onto the adpater allow for the filter to rotate. What is the purpose of being able to rotate the polarizer when it is mounted?

LR Max
01-10-2007, 08:46 AM
The "circular" polarizer filter allows you to adjust how much polarization (for the lack of a better term) you want. Go ahead and bolt it up to the camera and then go outside on a clear blue day. Look in the viewfinder as you rotate the lense while you have the camera pointed at the blue sky (away from the sun!!). Then observe.

This is another little trick to have in your bag.

GaryS
01-10-2007, 08:54 AM
Polarizers are hard! But worth it.

Good info on them here (http://dpfwiw.com/filters.htm#polarizers)

mattdm
01-10-2007, 02:19 PM
This is the nature of the filter -- it filters out light not coming from a certain direction. Rotating the filter allows you to change that direction. Rotate it until you see what you want to see.

sla
01-17-2007, 05:07 AM
Hi
Here (http://www.cs.mtu.edu/~shene/DigiCam/User-Guide/filter/polarizer.html) you have some info about polarizing filters and about adjusting.
And here (http://www.colorado.edu/physics/2000/polarization/polarizationI.html) you can "rotate" the filter.
regards

kgosden
01-17-2007, 08:43 AM
A pretty interesting demo, but it misses the other important use of a polarizer filter; windows. When you have reflections on window glass the polarizer can often be used to either eliminate or enhance the reflection on the glass. This is important if your subject is on the same side of a window as your camera or on the far side.