Does Cir Polariser introduce warmer color cast?


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May 27, 2003
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#1
Just bought a b+w cp recently for my canon 17-40 lens, tested it and it seems to introduce a warmer color cast.. is it normal? Of course, the blue sky looks darker (in facts it looks dimmer overall)

And is there a easier way to use the CP rather than keep on rotating and kind of "guessing" based on the limited view finder? or am i doing it right? :dunno:

Thanks in advance. :)
 

sriram

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#2
Depends on the quality of the filter. I had a cheap cokin circ-pol which gave a blue cast. My B+W c-pol is dead neutral.
 

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#3
Err.... I think I was not clear in my 1st question.

Below are 2 shots with B+W CP on my 17-40 lens..

1st one is one with CP turned to have the darkest blue sky...

http://www.flickr.com/photo_zoom.gne?id=107608482&size=l

2nd one is one with CP turned to have the lightest blue sky

http://www.flickr.com/photo_zoom.gne?id=107608483&size=l

When CP was used and turned to have the darkest blue sky, the shot seems to be warmer...

??:dunno:
 

9uowei

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Feb 13, 2006
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zipper,

i tried shooting with my hoya CPL, also on 17-40 today and got the same result. but i shoot in raw and was able to adjust the colours to the "correct" shade. this leads me to suspect that its a white balance issue and not the result of using the CPL. i still think the picture should turn out like #1 if u had used the CPL correctly.

zipper said:
Err.... I think I was not clear in my 1st question.

Below are 2 shots with B+W CP on my 17-40 lens..

1st one is one with CP turned to have the darkest blue sky...

http://www.flickr.com/photo_zoom.gne?id=107608482&size=l

2nd one is one with CP turned to have the lightest blue sky

http://www.flickr.com/photo_zoom.gne?id=107608483&size=l

When CP was used and turned to have the darkest blue sky, the shot seems to be warmer...

??:dunno:
 

#5
zipper said:
Just bought a b+w cp recently for my canon 17-40 lens, tested it and it seems to introduce a warmer color cast.. is it normal? Of course, the blue sky looks darker (in facts it looks dimmer overall)

And is there a easier way to use the CP rather than keep on rotating and kind of "guessing" based on the limited view finder? or am i doing it right? :dunno:

Thanks in advance. :)

CP are neutral. It does not influence the result of using the CP like making it warmer or cooler. As it was pointed out by 9uowei it is more an issue with your white balance issue. Have you set your white balance to auto? If so...each time you aim at a scene, the white balance sensor is calculating the colour temperature of the scene. It is done in real time as far as I know with digital cameras. And sometimes even the same scene can produce slightly difference colour temperature in two difference shots. This happen even when you shoot without any CP attached. Coming back to your CP, well as you might know, a CP eliminates glares on some reflective surfaces or lights coming towards your camera lens from certain angles....the elimination of those glare would cause the white balance to recalculate the temperature again...so there is a slight change in temperature in your next shot. I suspect that is what caused it.

As to whether cheap CP or high branded ones will cause this? I am not sure it does. At least not for me. I still have a cheap lesser known brand CP and I have the B+W one. I have used them both and they work as good or bad as the white balance sensor would work with them mounted on the lens.

There is no easier way to use a CP. The viewfinder is the only way to do this...well at least to me it is for almost 20 yrs that I have used a camera. That is what a viewfinder is for and I bet it will be this way for many more years to come. I never have to guess how to use the CP...one look in the viewfinder, turning the rim round to examine my shot and analyse the best light quality I am looking for and then I click my shutter. How much more easier then that?

Just a further tip...learn more about white balance and now it works with your DSLR or Film if you are using a 35mm. And how to best to avoid it.
 

aloyteo

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#6
actually to test ur cp more accurately and to get the best results u should try shooting in the late evening when the sun is at a lower angle so the degree of polarisation would be much more prominent. from the shadows of the tree in ur pics i can see that u shot those pics at around 1-2pm? haha just some of my thoughts...
 

May 27, 2003
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#7
aloyteo said:
actually to test ur cp more accurately and to get the best results u should try shooting in the late evening when the sun is at a lower angle so the degree of polarisation would be much more prominent. from the shadows of the tree in ur pics i can see that u shot those pics at around 1-2pm? haha just some of my thoughts...

You're right! I was shooting around 12pm++... :)
 

May 27, 2003
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#8
Thanks 9uowei and sammy888, i think i understand where was my problem (hehe.. not the CP problem!). Yes, I was using AWB.

Thanks for the great help and detailed explanation...

:embrass: how stupid i was!
 

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