Front fitting circular polarizer for 'P' filter holder

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I hope I've explained this correctly... I have got a set of 'P' size ND Grads for some landscape and coastal shots I want to take, with a filter holder, all from SRB Griturn (Hitech filters). Really happy with them etc.. but realised the problem when using a circular polarizer i.e. the fitting path is:

lens > polarizer > filter holder > P filters

Then I saw this:

http://link.brightcove.com/services/player/bcpid1847353720?bctid=17252658001

In this video the chap assembles his kit for the shoot thus:

lens > filter holder > P filters > polarizer

(the whole video is interesting but the bit I am referring to is at 9.25).

I can't seem to find a holder or front attachment for my holder to put my polarizer on the front. Is this a custom mod or can anyone point me in the right direction please.
 
I haven't looked at the link as I'm browsing on my phone.

IIRC lee filters have the polarizer bolted on the front, so maybe they are using that
 
Sounds like the Lee set up.

You can get an option 105mm front ring which a polariser can fit into.

Why does it matter if your CPL is in front or behind other filters? The same light will still be reaching the sensor
 
Uneducated_Rick said:
Why does it matter if your CPL is in front or behind other filters? The same light will still be reaching the sensor
Click to expand...

It just felt a bit tricky rotating the CPL and then lining up the ND grad - it just looked sooo much easier having the CPL at the front.

I am guessing (knowing my luck) that Lee don't do a filter holder for P size 84mm filters.?
 
Even with the CPL at the front the whole holder still rotated so he had to line the NDG back up and then re-rotate the CPL.

From memory the only Lee holder is 100mm wide, or 4"
 
Hi. Lee do two holders but neither of which are Cokin sized.
With regard to the position of the polariser, you should always have the polar as the first filter the light from the subject sees. The reason is that certain materials used in filters can de-polarise light and will give weird results.
 
instamatic said:
Hi. Lee do two holders but neither of which are Cokin sized.
With regard to the position of the polariser, you should always have the polar as the first filter the light from the subject sees. The reason is that certain materials used in filters can de-polarise light and will give weird results.
Click to expand...

If the other filters have a polarising affect it won't matter whether your CPL comes first or last it will still have the same result
 
instamatic said:
Hi. Lee do two holders but neither of which are Cokin sized.
With regard to the position of the polariser, you should always have the polar as the first filter the light from the subject sees. The reason is that certain materials used in filters can de-polarise light and will give weird results.
Click to expand...


Then surely the Polarizer needs to be closest to lens to negate what the filters in fromnt of it are doing. If you have it at the front the subsequent filters will "de-polarize" the light.???
 
The words 'CAN' and 'WORMS' spring to mind here.
 
The point of a polariser is to manipulate the polarised light that comes from the source, such as the sky. Hence if the sky has polarised light within it, we need the filter to "see" this and to consequently act on it, and reduce its intensity for example. If a de-polariser of some type is used first before the polariser, then the light from the source(the sky) is de-polarised and the polarisation filter will now have no effect.
 
That was my understanding.. and to add to all my initial confusion, this months copy of PhotoPlus has (rather good timing) a feature on buying filters. one the HiTeck section they show what looks like a filter holder with polarizer (or at least the fitting fir it) on the front.!?

So they must exist for my filters ?
 
instamatic said:
The point of a polariser is to manipulate the polarised light that comes from the source, such as the sky. Hence if the sky has polarised light within it, we need the filter to "see" this and to consequently act on it, and reduce its intensity for example. If a de-polariser of some type is used first before the polariser, then the light from the source(the sky) is de-polarised and the polarisation filter will now have no effect.
Click to expand...

Your understanding of the physics of light is wrong and the sky cannot have polarised light in it as being polarised is not a property of light :thinking: I can't really explain this very well in words

Light waves oscilate along any axis, a polariser is used to remove all light except that on a particular plane. A polarising filter is not used to "see" polarised light, it is used to remove all light except for a particular plane
 
Uneducated_Rick said:
Your understanding of the physics of light is wrong and the sky cannot have polarised light in it as being polarised is not a property of light :thinking: I can't really explain this very well in words

Light waves oscilate along any axis, a polariser is used to remove all light except that on a particular plane. A polarising filter is not used to "see" polarised light, it is used to remove all light except for a particular plane
Click to expand...

Just to add to this, light is scattered in many directions during its journey to our eyes / sensor /film. What a polariser does, I think, is to remove the scattered light so that the light we see through the filter or that hits the sensor/film is "polarised light".

Light is also polarised during the reflection process from the surface of water. That explains why a reflected landscape looks darker than the actual landscape.

In practical terms it can look better if you use a ND grad on the actual landscape when you're also photographing its reflection.

If this was posted on a physics forum I'd probably be shot down in flames, however....
 
Boney Boy said:
I hope I've explained this correctly... I have got a set of 'P' size ND Grads for some landscape and coastal shots I want to take, with a filter holder, all from SRB Griturn (Hitech filters). Really happy with them etc.. but realised the problem when using a circular polarizer i.e. the fitting path is:

lens > polarizer > filter holder > P filters

Then I saw this:

http://link.brightcove.com/services/player/bcpid1847353720?bctid=17252658001

In this video the chap assembles his kit for the shoot thus:

lens > filter holder > P filters > polarizer

(the whole video is interesting but the bit I am referring to is at 9.25).

I can't seem to find a holder or front attachment for my holder to put my polarizer on the front. Is this a custom mod or can anyone point me in the right direction please.
Click to expand...


I have just looked at the video and it does look like a lee set up. I have just brought a similar set up that is used in the video. All I would say is do a search for 105mm cpl's they are not cheap.
 
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