Cokin Pola Red p161 vs Straight Red filter in Bw?

[l2oBiN]

What is the difference in effect between these filters for bw photography? Would also be good if someone posted an example.

[Peter Gomena]

The polarized red filter would avoid stacking filters if you want to really cut haze in a scene. This would be especially helpful with wide angle lenses on medium-format cameras. My Hasselblad's 50mm lens vignettes like crazy with 67mm stacked filters. Image quality also may suffer with stacked filters.

Peter Gomena

[l2oBiN]

Do you mean that the pola red is a polarizer and a redfilter? Is there any areas which it assigns more red to?

[Peter Gomena]

Red cuts blue and green from the visible spectrum. It will reduce density in shadow areas illuminated by clear blue sky, a blue sky, and darker green foliage. Combining it with a polarizer will further darken blue sky and will remove some reflections from the scene. Depending on the density of the red filter, you will lose a total of 3 to 5 stops of light. I don't own one of these, but I assume Cokin has combined the two into one.

Peter Gomena

[l2oBiN]

does anyone have any example photos?

[l2oBiN]

I am still unclear o exactly what this filter does. Does it act as a polariser and has a continuous red placed over the top (ie same as combining a polarizer with a red filter) or does it act as a blue/yellow polariser assigning reds just to particular polarized light?

[Bill McMannis]

I am still unclear o exactly what this filter does. Does it act as a polariser and has a continuous red placed over the top (ie same as combining a polarizer with a red filter) or does it act as a blue/yellow polariser assigning reds just to particular polarized light?

The filter is made of two components: One "grey" polaraized glass and , in this case, a polarized red element. You can rotate the red element for darker red much the same way a traditional polarized filter works for "darker" grey. The range seems to be between one half and two and a half stops. It is like stacking a red filter with a polarizer.

You can get other color elements as well: I have blue and yellow in addition to the red.
The polarized red REALLY can make clouds pop in B&W landscapes. I never go in the field without my pola red and pola yellow.

Yes, you do need to be careful with vignetting. This is a thick filter.

[Erik Larsen]

A little off topic I guess, but I have a Sing ray gold and blue polarizer which basically changes between yellow and blue tint as you rotate the filter. My question is if I use it for b/w shots will the yellow portion of the filter darken the sky and the blue portion lighten the sky. It works as expected for color work, but I haven't used it for b/w instead using just a regular polarizer for b/w. Anyone know for sure?
regards
Erik