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-   -   White balance with polarizer? (https://www.dvinfo.net/forum/open-dv-discussion/18011-white-balance-polarizer.html)

Dan Lahav December 6th, 2003 01:53 AM

White balance with polarizer?
 
I'm having some probs with my tiffen polarizer. It doesnt really seem to be very effective. Last time i had it on, while editing, i noticed half the screen was purple (didnt notice it on the LCD at the time). Is this because i've been white balancing with it on? i've turned the polarizer around several times with the DVX and am not getting that "intense blue sky" everyone said i'll get outta this thing. It's only *slightly* darker. Also, is it apropriate to use the UV filter and Polarizer at the same time? Thanks

Jeff Donald December 6th, 2003 03:34 AM

A polarizer is most effective when the optical axis of the lens is at a 90 degree angle to the sun. This is the maximum angle for polarization. Angles greater of less than this will not produce as dark a sky. For example if you point the camera near the sun the polarizer will not create a blue sky.

A wide angle lens will often create a problem in the use of polarizers. Because the wider angle of view causes the degree of polarization to vary, the color of the sky will vary from one side of the scene to the other.

Some polarizers have a noticeable color tint to them. Some polarizers have a warming effect built in. Better polarizers are usually color neutral. You might consider upgrading to a B + W, Heliopan or the better grade of Hoya filters (SHMC+ ?). Colorization in Tiffen polarizers has been noted on the forums before. Similar posts can be found in the archives.

I would not stack a UV with polarizer. The added glass element just makes it more likely to cause flare and degrade the image.

Dan Lahav December 6th, 2003 03:48 AM

thanks jeff. Ive been shooting in hazy environments with low sun, so i guess thats my problem. I've used a tiffen polarizer on my 35mm camera and its beautiful... are you sure i should upgrade?

Jeff Donald December 6th, 2003 04:02 AM

If you were shooting color negative 35mm film, the color cast was removed by the film processor when they printed your negs. People have posted about color casts from Tiffen polarizers in the past. I've also noted it occasionally in some of my students photos. If the color cast is that objectionable, then ask yourself if you want to color correct all your DV footage and render it.


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