Re: Stacking filters together

[Ben Kreunen <ben@xxxxxxxxxxxxxxxxxxxxxxx>]

At 10:22 AM 5/16/00 -0500, you wrote:
>as said before, the yellow is redundant. and you might want to check for 
>vignetting on the final image with that many filters stacked.

Yes the yellow filter is redundant since it overlaps with the red filter 
but has a broader range.  The polarising filter will be more of an ND 
filter in this case. It looks darker to you but the spectral properties 
haven't really changed. If you want to cut down on the visible light, pick 
a filter that blocks red light... eg. #47B or #58. Either of these will 
block nearly all visible light when used with a #25.

There's an interesting exercise in cost comparison and effectiveness 
compared to IR filters for someone....

>     I stack the Red325a+yellow#8+Polarizer together to get something around
>a red#29, or darker effect, it actually looks darker than a red#29. You are
>all correct in your assumption that I am not affecting I.R., what I am doing
>is lowering the level of the visible spectrum even further. This way I am
>getting more towards an 87, or 89 effect.


Cheers

Ben

===================================
http://www.bigbenpublishing.com.au/
===================================

*
****
*******
******************************************************
*  To remove yourself from this list, send:          *
*         UNSUBSCRIBE INFRARED                       *
*       to                                           *
*         MAJORDOMO@xxxxx                            *
*----------------------------------------------------*
*   For the IR-FAQ, IR-Gallery and heaps of links:   *
*  http://www.a1.nl/phomepag/markerink/mainpage.htm  *
******************************************************