Polarizing filter advice

[David Evans]

When using a polarizing filter along with other filters, does the poalarizer have to go on the outside (with any other filter between the lens and the polarizer)?

[IanG]

That's the easiest way as you need to be able to easily rotate it, but it's not that critical.

Ian

[Joanna Carter]

When using a polarizing filter along with other filters, does the poalarizer have to go on the outside (with any other filter between the lens and the polarizer)?

That depends on the nature of the other filters being used. If the other filters are polyester, the advice is to put the polariser on the outside but, if they are resin, it is best to place it nearest the lens.

Although Lee sell a holder adapter for screw-in filters, where the polariser is placed at the front of the holder, they also sell the Professional Kit, where a square polariser can be placed in the rear holder and rotated independently of a second holder, mounted in front.

The reason for putting the polariser in front of polyester filters is to avoid interference patterns that can occur between these thin and flexible filters; whereas, with resin filters, placing the polariser next to the lens ensures that, whatever the other filters do to scatter and refract the light, the last thing to happen is to polarise it correctly.

[Charles Twist]

The reason for putting the polariser in front of polyester filters is to avoid interference patterns that can occur between these thin and flexible filters; whereas, with resin filters, placing the polariser next to the lens ensures that, whatever the other filters do to scatter and refract the light, the last thing to happen is to polarise it correctly.

Yes, but (i) if you place the polariser on the outside and then rotate it, you're basing your result on the polarising effect of your stack of filters and so will retain control over the results and (ii) the point of the polariser is to cut out a certain kind of light in the field: if the polarised light subsequently gets depolarised or scattered by your other filters, who cares? you've still gotten rid of the light you don't want.
Personally, I have the polariser on the outside, for convenience.
Best regards,
Charles

[timparkin]

When using a polarizing filter along with other filters, does the poalarizer have to go on the outside (with any other filter between the lens and the polarizer)?

That depends on the nature of the other filters being used. If the other filters are polyester, the advice is to put the polariser on the outside but, if they are resin, it is best to place it nearest the lens.

Although Lee sell a holder adapter for screw-in filters, where the polariser is placed at the front of the holder, they also sell the Professional Kit, where a square polariser can be placed in the rear holder and rotated independently of a second holder, mounted in front.

The reason for putting the polariser in front of polyester filters is to avoid interference patterns that can occur between these thin and flexible filters; whereas, with resin filters, placing the polariser next to the lens ensures that, whatever the other filters do to scatter and refract the light, the last thing to happen is to polarise it correctly.

Does the scaterring of light by resin filters alter the polarity of that light? I thought it would remain the same (otherwise reflections would also change the polarity and would not be filtered by polarisers?)

The 'pro' kit isn't only for polarisers (although it obviously can be used for that). I'd be surprised at seeing a difference in the end results dependant on the order of the filters (although it would be a happy surprise at discovering I was wrong and learning something new).

Tim

[dave_whatever]

I use a smaller polariser next to the lens instead of the big Lee one on that ring. Optical considerations aside, it means you've not got to jump through hoops to use a hood, and overall is a lot lighter and vastly cheaper than a 105mm polariser in a Lee ring.

In practice I don't think front or back makes any odds if you're not using those polyester filters. Interestingly Lee chose to implement their polariser on the front, whereas Cokin's goes at the back.

[Joanna Carter]

As Dave says, I don't think it make much difference unless you are using polyester filters. I just took the advice of a senior technician at a filter company and have been happy with the results.

[David Evans]

Thank you for all the excellent, helpful and quick responses!
I am trying to work out how to polarize a lens with a 95mm filter thread, or a 112mm thread if I have the centre filter attached.
I already have a 105mm polarizer for the Lee holder, so think the answer is to get a step down (or is it up?) ring for that polarizer, or possibly a Lee 95mm adapter (but this may vignette) and not bother with a centre filter when using the polarizer.
I don't anticipate using a polarizer against the sky with this lens, so attaching a centre filter is less critical.

[dave_whatever]

Hows about sticking the polariser on the rear of the lens? You'd maybe have to recheck focus but it should work. If there's no threads on the back then use blutack.

[Joanna Carter]

Hows about sticking the polariser on the rear of the lens? You'd maybe have to recheck focus but it should work. If there's no threads on the back then use blutack.

Not a good idea, this can not just shift focus, it can also introduce a possible difference in focus towards the edges of the image.

[dave_whatever]

I suspect any field curvature is less of an issue when shooting stopped down though, and if its a long lens then even moreso. Obviously it's something you'd want to test on any particular lens/filter combo before trying it in anger!

[jb7]

I take it that's a 72mm XL?

I've got a 112mm Kaesmann cpl, if you're interested-
used it once, can't see myself using it again, am open to a reasonable offer...
Though I'm away for a week in the morning-

Using the centre filter, a polarizer has to go on the outside...