Circular Polarizer and Ultra Wide Lenses - workable?

EdinburghGary

EdinburghGary

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Guys,

Another thread has got me thinking about purchasing another Circular Polorizer (last one got wrecked), however I have a concern.

I remember when using it at 10mm on crop (sigma 10 to 20), that the effects were HUGELY worrying. I got a BLOB of deep blue sky, with massive fall off either side. This was using the HOYA Digital Pro model - £140 when I bought it.

Also, whilst on Skye, I borrowed the same filter from Woodsy, and using it on my 24 to 70, the same problem was evident.

So my question, who is currently using one on an ultra wide, and how do you overcome the problem? Do you need to take multiple exposures and blend?

Gary,
 
I have a Sigma 10 - 20 and I never bother with the CP because of the effect it has.
 
I have a CPL on a Canon 10-22 and use it all the time! It really doesn't bother me, and in fact I usually like it. Adds a bit more interest.

Sure you can get patches or bands of uneven polarisation depending on the angle of the sun, not always, but as you rotate the polariser it moves and fades. It's rarely an unsightly blob and if it is, then either dial it out completely and still get the polarising benefit on foliage etc, or take it off.

I don't see the problem. It certainly doesn't depend on the type or brand of polariser you have.
 
HoppyUK said:
I have a CPL on a Canon 10-22 and use it all the time! It really doesn't bother me, and in fact I usually like it. Adds a bit more interest.

Sure you can get patches or bands of uneven polarisation depending on the angle of the sun, not always, but as you rotate the polariser it moves and fades. It's rarely an unsightly blob and if it is, then either dial it out completely and still get the polarising benefit on foliage etc, or take it off.

I don't see the problem. It certainly doesn't depend on the type or brand of polariser you have.
Click to expand...

See here for an example of what I used to see:
http://www.kenrockwell.com/tech/images/KEN_6031-polarizer.jpg

Gary.
 
I do use one at 24mm on my 24-70 although the affect at 24mm is something you need to be careful with, but you can dial it out, or dial it atleast until the point it becomes pleasing. Bear in mind I'm no landscape tog though. I wouldn't want one wider than 24mm.

Just for an example the following was taken at 24mm with a CPL & no further processing http://www.talkphotography.co.uk/forums/showthread.php?t=132858

Hugh
 
Its all about the sun being at 90Deg to view
If you think of how wide your FOV is and where the sun is you will see most of the time it will not have an even effect BUT saying that I have and use one with out much problem, yes the blue sky will fad to one side or the other but you can use that in your image.
 
Hmm, I wonder whether this is a situation where a linear polarizer is more useful.
I was using the Canon 10-22, this photo is at 12mm, with linear polarizer.
Please excuse the thumb on the left!



Bit of a boring photo I know, but I wanted the widest possible to demonstrate.
 
coldpenguin said:
Hmm, I wonder whether this is a situation where a linear polarizer is more useful.
I was using the Canon 10-22, this photo is at 12mm, with linear polarizer.
Please excuse the thumb on the left!



Bit of a boring photo I know, but I wanted the widest possible to demonstrate.
Click to expand...

Linear poloriser? If it does what I am thinking, it sounds very useful.

Gary.
EDIT: It doesn't, and apparently renders the camera metering useless?
 
EdinburghGary said:
See here for an example of what I used to see:
http://www.kenrockwell.com/tech/images/KEN_6031-polarizer.jpg

Gary.
Click to expand...


My first thoughts when I saw what's from the link, ouch .. that's horrible!

I've never had such issues with CP on my 24-70 mounted on D700. There can be times when there is some fall-off, but what I've learnt to do is simply reduce the CP's effect.

Having it mounted all the time means I am in control of when, and how much effect I want to allow on my shots.

I used to use Nikon CP, toyed with Hoya for a short while, moved to Marumi, and am now with Heliopan .. these have been the best so far.

I am thinking of getting B+W, not because I am dissatisfied with Heliopan, but because I did the silly mistake of not buying the Kasemann version .. and B+W Kasemann are just as expensive as the Heliopan, so I might as well go with them.

If I am not mistaken, StewartR rents the Hoya version, may be worth renting before buying. However, if you opt to buy one and then find it unsatisfactory, you can recoup most of your outlay, by selling it here.
 
EdinburghGary said:
See here for an example of what I used to see:
http://www.kenrockwell.com/tech/images/KEN_6031-polarizer.jpg

Gary.
Click to expand...

Yes I know that example from KR :lol: He doesn't pull his punches.

But I have examples where the sky is darker than that, shot at 10mm on a crop body, where the darkening is perfectly even across the frame. They were taken in Greece, mid summer, mid day, with the sun perfectly overhead. Actually, the polarising effect is not strictly even - it is very dark at the top and fades to much lighter at the horizon. There is still a dark patch, but it's even across the frame horizontally, and uneven top to bottom. But it looks okay.

I still don't see the problem. If you get an uneven patch, then rotating the filter can shift it across the sky, maybe to an attractive position. Turn it further and the patch will gradually fade and vanish as the sky lightens, turn it further still and you will lose all polarising effect on the sky, but still get rich foliage and foreground. Or zoom in a bit and cut it out.

Heck, whoever said you must always use a polariser, and always to max effect? Every other filter is used as and when the effect works, moderated accordingly, and not used when it doesn't do the job. I would say that grads are much less controllable and obvious in this respect, but then they don't always suit every sky shot.

If I only had one filter, it would be a polariser by a mile :)
 
HoppyUK said:
Yes I know that example from KR :lol: He doesn't pull his punches.

But I have examples where the sky is darker than that, shot at 10mm on a crop body, where the darkening is perfectly even across the frame. They were taken in Greece, mid summer, mid day, with the sun perfectly overhead. Actually, the polarising effect is not strictly even - it is very dark at the top and fades to much lighter at the horizon. There is still a dark patch, but it's even across the frame horizontally, and uneven top to bottom. But it looks okay.

I still don't see the problem. If you get an uneven patch, then rotating the filter can shift it across the sky, maybe to an attractive position. Turn it further and the patch will gradually fade and vanish as the sky lightens, turn it further still and you will lose all polarising effect on the sky, but still get rich foliage and foreground. Or zoom in a bit and cut it out.

Heck, whoever said you must always use a polariser, and always to max effect? Every other filter is used as and when the effect works, moderated accordingly, and not used when it doesn't do the job. I would say that grads are much less controllable and obvious in this respect, but then they don't always suit every sky shot.

If I only had one filter, it would be a polariser by a mile :)
Click to expand...


You are now responsible for my next purchase, I really hope I can benefit from owning it.

Gary.
 
When I owned the 10-20 I also used a Hoya Pro 1 D polariser...I would say that 70% of the time I tried it the effect was just too uneven and spoilt the image, 30% of the time it was worthwhile.

Personally I think it's worth having one, just make sure if it's an important shot to take one with & without the polarising effect - just to be on the safe side !!

Simon
 
boyfalldown said:
they're not good with modern(contrast based) focusing systems either

Hugh
Click to expand...

Contrast based focusing systems are fine with polarisers, but anyway they are not used outside compacts (except for Pano G1 and GH1, and new Oly E-P1).

It is phase-detect AF that is foxed by linear polarisers, or rather it is the potential clash of polarisation planes when light for the AF is polarised for a second time via the camera's piggy-back mirror. Hence the creation of the circular polariser which is a normal linear polariser with a quarter wave plate stuck on the back, which effectively de-polarises the light again so the camera doesn't get all unnecessary.

Some metering systems are also fed via a half-mirror and they too can get confused when a linear polariser is used. It depends on whether the two polarised planes coincide or not. But anyway, I've not even seen a linear polarising filter advertised for years as circular one have just taken over.

BTW, I've just got the new Hoya HD Circular Polariser which only reduces exposure by 1.1 stops. It's excellent, and worth 0.7 stops free light over my outgoing Pro1 :D
 
I have the 105mm B+W and have to say it is lovely, here is very quick test I have just done off my balcony sorry for the vignette but I have just stuck a extra holder on my Lee system and now it is too far out so need to take it back down to 2 slots ;)

All taken with the 24-70mm on a D3 with AP F10 @ 24mm

The first 2 are with the Polarizer turned on and off so to speak and the last one is with no Polarizer.

dsc8498.jpg


dsc8499.jpg


dsc8500.jpg
 
coldpenguin said:
Hmm, I wonder whether this is a situation where a linear polarizer is more useful.
I was using the Canon 10-22, this photo is at 12mm, with linear polarizer.
Please excuse the thumb on the left!



Bit of a boring photo I know, but I wanted the widest possible to demonstrate.
Click to expand...

Main problem there, if there is one, is vignetting - both optical and mechanical. Polarising effect looks quite alright to me :thinking:
 
EdinburghGary said:
Linear poloriser? If it does what I am thinking, it sounds very useful.

Gary.
EDIT: It doesn't, and apparently renders the camera metering useless?
Click to expand...

Not necassarily, that was in Av mode. conversion was to set to 800px, there has been no other messing. (and if you are shooting landscapes, you do usually have time to review the picture, and re-compose/retake)
A linear polarizer is not much different from a circular polarizer.
It would be easier to say, that a circular polarizer, is a linear polarizer PLUS extra messing around. The extra messing around takes the polar filtered light, and attempts to convert it back to non-polarized light. This can affect the angle of the light comming through to a small extent. This can cause your vignetting, as there will be a filter incorporated into the sensor which tries to only accept parallel light. At the edges, there will be more of this angular dispacement caused by the second phase of the circular polarizer.

Now, with metering, if you stack two (yes two) linear polarizers, you can modify the total amount of light passing into the system, as if you had an adjustable ND filter. With circular polarizers this is not possible (well, you could do it with source->linear->circular->sensor in that order only).

boyfalldown said:
they're not good with modern(contrast based) focusing systems either

Hugh
Click to expand...

This is something I hear a lot of, and is almost a myth. I haven't had a problem focusing (even when I use one on a 300mm shooting moving subjects). On some older/cheaper cameras, which have compromises in the way that they perform the focusing tests, then there are problems. On modern/decent cameras there should be no problem.


Vignetting probably due to not having used a thin filter, it was standard width.
 
Personally I'd say you were asking for problems using a polariser on a lens as wide as 10mm. Even at 28mm uneven polarisation can be a nuisance, and at 24mm it is even more noticeable. I find you have to be quite careful using a polariser on WA lenses, especially on a clear blue sky.

Not that it ever stops me, mind you.

On Snapper73's pictures of a stunning sky at 24mm uneven polarisation is not really noticeable but it may be masked wholly or partially by the clouds. It is difficult to tell if the view is actually at 90 degrees to the sun - if not there may be very little actual polarisation visible.

Hoppy describes a situation where little polarisation would be evident anyway - mid-day, mid-summer, sun perfectly overhead. (Actually it would only be perfectly overhead on the equator, but that's another matter.)

Polarisers are also useful where no sky is visible (wet leaves in woodland, for example), so my advice would be - go for it, but use it carefully..
 
coldpenguin said:
Not necassarily, that was in Av mode. conversion was to set to 800px, there has been no other messing. (and if you are shooting landscapes, you do usually have time to review the picture, and re-compose/retake)

A linear polarizer is not much different from a circular polarizer.
It would be easier to say, that a circular polarizer, is a linear polarizer PLUS extra messing around. The extra messing around takes the polar filtered light, and attempts to convert it back to non-polarized light. This can affect the angle of the light comming through to a small extent. This can cause your vignetting, as there will be a filter incorporated into the sensor which tries to only accept parallel light. At the edges, there will be more of this angular dispacement caused by the second phase of the circular polarizer.
Click to expand...

This doesn't quite ring true to me :thinking:

Now, with metering, if you stack two (yes two) linear polarizers, you can modify the total amount of light passing into the system, as if you had an adjustable ND filter. With circular polarizers this is not possible (well, you could do it with source->linear->circular->sensor in that order only).
Click to expand...

Yes, has anybody tried a linear polariser screwed into a circular polariser, to get an infinitely variable ND filter? Why hasn't this caught on? I think you can buy something but very expensive - Singh Ray?

This is something I hear a lot of, and is almost a myth. I haven't had a problem focusing (even when I use one on a 300mm shooting moving subjects). On some older/cheaper cameras, which have compromises in the way that they perform the focusing tests, then there are problems. On modern/decent cameras there should be no problem.
Click to expand...

Not a myth at all, just that the circumstances that might provoke it are very rare. It just seems an unnecessary risk when you can just use a circular polariser and completely avoid any problems.

Vignetting probably due to not having used a thin filter, it was standard width.
Click to expand...

Looks like regular optical vignetting caused by a low f/number. My Canon 10-22 also does exactly that at f/3.5-4, but it's gone by f/5.6.
 
HoppyUK said:
....
Yes, has anybody tried a linear polariser screwed into a circular polariser, to get an infinitely variable ND filter? Why hasn't this caught on? I think you can buy something but very expensive - Singh Ray?
....
Click to expand...

:p What are you trying to do to us, Hoppy!? It's hard enough to work out the right exposure for a 10 stopper, without introducing more variables into the equation :gag:.

;)
 
Naboo32 said:
:p What are you trying to do to us, Hoppy!? It's hard enough to work out the right exposure for a 10 stopper, without introducing more variables into the equation :gag:.

;)
Click to expand...


:agree:

I have to say, going into that kind of technicality fried my brains too. May as well been speaking Klingon
 
Wail said:
:agree:

I have to say, going into that kind of technicality fried my brains too. May as well been speaking Klingon
Click to expand...

LOL :) The concept is very simple. If you imagine a polarising filter to be like a venetian blind (which it pretty much is) then if you have another polarising filter in front of it, and turn it through 90 degrees, it will go black.

The Singh Ray version is here: http://www.singh-ray.com/varind.html It should work as both a polariser and a variable ND simultaneously, in which case the $340 price isn't quite so horrendous (no, it is still horrendous). It goes from +2 stops ND to +8 stops which is a perfect range.

It's a bit chunky unfortunately, which means it will likely vignette on super wides, but I don't see why putting a cheap linear polariser in front of a normal polariser shouldn't work just fine - in theory. It's got to be worth a try, if you can get what amounts to a couple of ND filters for maybe £30 or so. I would only use it three time a year anyway. I'll give it a try next time I'm in Jollops.

Edit: Singh Ray doesn't mention a polarising effect, and with a minimum of only two stops reduction, that doesn't sound exactly how a twin-polariser set up would work. Just thought I'd mention it... :thinking:
 
HoppyUK said:
This doesn't quite ring true to me :thinking:
Click to expand...
I am making the assumption that the cameras use collimators to improve the quality of the sensed image (these can be incorporated per cell as a boundary partition). It is possible with the single ?cell? sensors (is that what they are called? the big lumpy things [technical term]) that this effect is reduced. Usually in imaging, you try and ensure that only parallel light beams (or rather, light perpendicular to the sensor) is detected, this reduces problems caused by wider apertures.

HoppyUK said:
Yes, has anybody tried a linear polariser screwed into a circular polariser, to get an infinitely variable ND filter?
Click to expand...
I use two linears personally

HoppyUK said:
Not a myth at all, just that the circumstances that might provoke it are very rare.
Click to expand...
I did say almost a myth. It is just that it seems as soon as someone mentions the word linear, a lot of people say 'it will /never/ work'

HoppyUK said:
Looks like regular optical vignetting caused by a low f/number. My Canon 10-22 also does exactly that at f/3.5-4, but it's gone by f/5.6.
Click to expand...

Probably is then, I often use Av mode and set the f/ to be as low as possible to get the light up
 
Chaz Photos said:
Its all about the sun being at 90Deg to view
If you think of how wide your FOV is and where the sun is you will see most of the time it will not have an even effect BUT saying that I have and use one with out much problem, yes the blue sky will fad to one side or the other but you can use that in your image.
Click to expand...

:agree:

These days I seem to use no filter more than anything. If I do use one then it is the polariser. Many times I have taken grads with me and never used them. So often they just make the light balance look wrong so unless the shot is really bad without them I just don't use them.
 
EdinburghGary said:
It doesn't, and apparently renders the camera metering useless?
Click to expand...

Not entirely. It will only affect AF system - metering will work fine. Actually, that chap on DPReview i mentioned in another thread, Iliah Borg, said there once that he uses mostly linear polariser since it affects the image quality less. As far as I understood it had something to do with different channel sensitivity (R, G and B are all slightly different) and the way polarisers work.

Anyway, if AF is not that important to you (and for landscapes it should not really be) then linear will work just fine - not to mention way less expensive.
 
Thanks for your reply ColdP :)

coldpenguin said:
I am making the assumption that the cameras use collimators to improve the quality of the sensed image (these can be incorporated per cell as a boundary partition). It is possible with the single ?cell? sensors (is that what they are called? the big lumpy things [technical term]) that this effect is reduced. Usually in imaging, you try and ensure that only parallel light beams (or rather, light perpendicular to the sensor) is detected, this reduces problems caused by wider apertures.
Click to expand...

Not quite sure I understand what you're saying, but the angle at which light hits the sensor is a big problem, unrelated to polarising filters. The image is only projected perpendicular to the sensor with long focal lengths, and the inverted telephoto design of wide angles helps this. It is one of the reasons Leica couldn't put a full frame sensor in the M8, but that's by the way :)

I use two linears personally
Click to expand...

That's interesting. How do you get on? What range of ND do you get?

I did say almost a myth. It is just that it seems as soon as someone mentions the word linear, a lot of people say 'it will /never/ work'

Probably is then, I often use Av mode and set the f/ to be as low as possible to get the light up
Click to expand...

:thumbs:
 
I have posted some other non-real photos of a doll's house experiment before. I couldn't really be bothered to do anything that scientific tonight. I have applied a white balance to the first picture, and copied to all of the others. Pictures F and G are improved a lot by a white balance on them. These are cheapo linear polarizers, Hoya Purple. The purple tinge is bad, but that is at a serious ND level I think (1/200 -> 4s =~ 9.5 stops at root 2)

The method here was taking a picture of a clock, with the reflection of a 50W GU10 directly at it.
Lens was 28-135, zoomed so that clock filled most of the frame. Autofocus was used to gain a focus, then lens changed to manual. As much care as possible was taken to not knock the lens. Nominal 0 was taken as the L from PL being at the top of the lens. In the last two photos, it isn't blur/movement of the lens, the white circle is the edge of the glass on the bulb.

Pictures in order of:


ABCD
EFGX

A - No polarizer - f/6.3 t=1/200
B - 1 Linear polarizer, nominal 0 degrees - f/6.3 t=1/80
C - 1 Linear polarizer, nominal 90 degrees - f/6.3 t=1/80
D - 2 linear polarizers, 1 nominal 0, 2 nominal 0 - f/6.3 t=1/40
E - 2 linear polarizers, 1 nominal 0, 2 nominal 45 - f/6.3 t=1/6
F - 2 linear polarizers, 1 nominal 0, 2 nominal 90 - f/6.3 t=4
G - 2 linear polarizers, 1 nominal 45, 2 nominal 135 -f/6.3 t=4

 
^^^ Thanks for that ColdP. I'll give it a try when I can get hold of an extra linear polariser.

But I'm wondering why it hasn't caught on as an ND technique, and am guessing that there may be uncorrectable colour casts to be found further along the line.

Thanks for taking the trouble - much appreciated :thumbs:
 
HoppyUK said:
^^^ Thanks for that ColdP. I'll give it a try when I can get hold of an extra linear polariser.

But I'm wondering why it hasn't caught on as an ND technique, and am guessing that there may be uncorrectable colour casts to be found further along the line.

Thanks for taking the trouble - much appreciated :thumbs:
Click to expand...

It works! :) I got a cheap linear polariser today. They are very hard to find; this one was in a second hand shop, Campkins in Cambridge for £10, and the wrong size, but it was fine for experiments.

I've just spent a couple of hours testing the ND range and colour balance, and it works just great as a variable ND filter over a range of +3 to +7 stops. I think that is a pretty much perfect range, but you can push it a stop or two further if you fiddle with colour balance but it suddenly goes blue when it gets right to the limit which is over +10 stops.

This is what I used. Regular circular polariser on the lens, mine is a Hoya HD which only increases exposure by 1.1 stops. I then fitted the linear polariser in front and when it is rotated for minimum effect the exposure was reduced by +3 stops. I then rotated it to get varying degrees of neutral density as the image goes dark, towards virtually black.

The first couple of cm of rotation make a couple of stops difference, which takes you down to +5 stops, and then very small movements make quite big changes. At the practical limit, say about +7 stops, just 2mm of rotation loses a stop so you would need to do your own checks and mark the filter ring carefully so you know where you are.

The other thing to be wary of is vignetting with wide angles, as you have two stacked filters in front of the lens - this should be okay with slim-mount filters though. And it is never a good idea to stack filters for reasons of image quality but if I can get a varyiable ND filter with a range of maybe +3 to +8 stops effectively for the price of an extra linear polariser, then I think that's a pretty good deal considering ND filters of this strength are around £100.

I'm now going to get a better quality linear polariser - I think Hoya do a single-coated linear for sensible money. When I've got is sorted I'll post pictures and details.

Edit: has anybody got a 77mm linear polariser looking for a new home? Must be coated. Or do you know where I can get one, maybe from a used dealer? Many thanks.
 
When I played around with two polarisers, I wondered whether it was a technique used to simulate night in B&W movie making.
 
jerry12953 said:
Hoppy, that's very interesting. I was wondering if it would work.

Maybe try the big 2nd hand dealers for another linear polariser? They probably have piles of them in a cupboard somewhere.
Click to expand...

Yeah, I'm going to have to ring around and see if I can pick up a cheapy. TBH, this technique is only worthwhile as a money saver, or you might as well just buy an ND filter and be done with it. I don't think that being able to vary the density is that much of a benefit in practise, and unless I can get a slimline linear polariser to stack in front, it will get vignette at the wide end of my 10-22 zoom (it's clear by 12mm though). Plus I'm not keen on stacking filters anyway, image quality and all that.

Thinking about it now, these are probably some of the reasons why this trick isn't very popular! :lol:

BTW Jerry12953, if that's your birthday, I am three days older than you :p
 
So it could be hoppy 9953, then? Presumable hoppy is not your Christian name? To be honest when I joined up I couldn't think of anything more original.

Re polarisers -

It could be that nobody else had thought of using 2 as a ND filter? Apart from SinghRay - that is. This whole idea of using 8 or 10 stop ND filter to create milky waves and clouds seems to have come from nowhere in the last 6 months or so. "At our age" we can spot a trend, can't we? Possibly even a fad?
 
I am surprised, I would have thought that it would be quite a common thing to do.

I just thought that it was all this scaremongering about linears not working with any camera ever that kept people away.
 
jerry12953 said:
So it could be hoppy 9953, then? Presumable hoppy is not your Christian name? To be honest when I joined up I couldn't think of anything more original.

Re polarisers -

It could be that nobody else had thought of using 2 as a ND filter? Apart from SinghRay - that is. This whole idea of using 8 or 10 stop ND filter to create milky waves and clouds seems to have come from nowhere in the last 6 months or so. "At our age" we can spot a trend, can't we? Possibly even a fad?
Click to expand...

You've guessed my PIN :eek: It's Richard 'Hoppy' Hopkins.

Using a heavy ND could be a fad, but I think that today this is perhaps a bit more enduring because digital doesn't have reciprocity failure issues. Back in the day, with film you could forget anything over a few seconds as just not worth the hassle, with exposure nightmares that could only be covercome with extensive trial and expensive error.

With digital, ten seconds is no problem at all, and ten minutes merely rather boring at the time. Smokey waterfalls are a bit predictable, but I rather like the look of smooth milky seascapes and you need a minute or more for that. Then Edinburgh Gary has posted some fantastic night shots, where he has got spectacular colour and movement out of nowhere with exposures of night sky over ten minutes. The image he's recorded in this link does not exist in real time, you can't really see it, but something magical happens over a period of several minutes where the light that you can barely see builds into spectacular colour and the clouds move. http://www.talkphotography.co.uk/forums/showthread.php?t=152395

coldpenguin said:
I am surprised, I would have thought that it would be quite a common thing to do.

I just thought that it was all this scaremongering about linears not working with any camera ever that kept people away.
Click to expand...

Yeah, it's not a new technique, but I'd certainly forgotten about it. But as I've found, it's not so easy or cheap, and just getting a linear polariser, preferably coated and in a slim mount, at the right price, is proving difficult.

You can't do it with a circular polariser and since linears have effectively been sidelined for many years now, almost nobody stocks them. Local dealers had nothing, Jacobs superstore had nothing, other nearby stores had nothing. I was lucky to pick up an ancient secondhand one in Cambridge. What I want is a nice top end B+W, but paying over £100 makes a nonsense of the whole idea when you can get a ten-stop B+W ND for less than that.
 
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