Intelligent Use Of A Circular Polarisor ?

[David]

I got a CP1 when I brought my Canon and my 10 months of experience in shooting places with water (seascapes, waterfalls, creekbeds) has taught me not to go anywhere near a water image without the CP attached- it produces better sharper water based images and I think I know why but I have no idea of the HOW which means I may not be getting the value of the CP at times.

My question is simple; a CP can be turned around 360 degrees when fitted to the end of my camera lenses. Is the CP going to produce the same results wherever you have it on the lens because it is completely the same all over ?

I remember reading about ND and GND filters around the same time and I know they have to be set by rotating the filter on the lens because half the filter is darker than the other part etc.

All i want is something that I can screw onto my camera to dull the blown out whites and underexposure of the surrounding area with waterfalls, for example, without having to check the filters position to make sure the darker part is aimed at the right spot.

IF the CP does not change the effect at any position on a 360 degree rotation when fitted to the lens I am going to be a happy camper because that is what I want.

Meantime I will Google CP filters and educate myself If I have time before my trip to Tassie in a few days, but if anyone can put an end to my anxieties about not using the CP intelligently please enlighten me.

THANKS

David.

[I @ M]

David, a couple of maybe useful links for you on CPls.

http://www.great-landscape-photograp...ng-filter.html

http://www.colorado.edu/physics/2000...rizationI.html

[ricktas]

Probably a bigger change in how a CPL works is related to the angle to the light source. Take your camera outside on a sunny day, aim it sort of near the direction of the sun and while looking through the viewfinder, turn the polariser and watch the effect. Then turn 90 degrees to the sun and do the same thing. Noticeably different result!

As you turn the polariser the effect increases and decreases, so turning it is important to get it to the 'right' spot for your scene. This right spot is related to the angle from the sun that you are facing.

So, just bunging the polariser on and shooting without making adjustments by turning it, is going to result in less than ideal results.

[Tannin]

Seeming to disagree with Rick but actually not, in a way, it mightn't be a bad idea to shoot with a CPL at random angles (which is essentially what you are doing now, Bagubun). When you first start with a polariser, you tend to twist it around to get the maximum effect all the time so you can "really see it doing some good". But after a bit of that you realise that the biggest effect isn't always the best effect, and you start to dial it back for a more natural look. In the end, as Rick says, you have to judge each shot opportunity on its merits and twist the CPL each time, deciding what setting will look best.

[arthurking83]

Now I'm going to freak Tony out by agreeing 100% with what he's said!

A Polariser isn't only for the purpose of making a blue sky blue or to remove glare of surfaces(like water) but has many other uses, which as Tony said is based on the way you use it(how much you want to rotate it.
The differences are subtle but if you do it carefully you'll see the differences, even at 15mins before sunset on an overcast evening.

I tend to keep the CPL on my ultra wide angle lens all the time, unless it doesn't give me an effect(that I like). And that means morning noon and night.

it almost always makes a difference to something, even if it's only to reduce the glare of a street lamp at night!

the only way you'll figure this out is by using it and committing that usage to memory.

Two silly examples of my use of a CPL recently:

Last week at Brighton beach, at night(about 2 hours after sunset.. maybe 3) The bright lights of the street lights were causing glare on the shiny painted suraces of the beach boxes.. CPL helped to achieve a better exposure, even though it added a few seconds to the exposure. Otherwise to get more shadow detail I would have had to burn out the highlights on the beach boxes.

Yesterday at the beach, 15 mins before sunset, but it was overcast the sun shone through a teeny sliver of cloud. I was pointed 180° to the sun(ie. directly behind me).
The water would have ended up looking too silvery(for my liking) and the CPL was used for two things. natural vignetting and to flatten the brightness of the distant water. that meant about 2/3rd less exposure which allowed me to capture slightly more shadow detail.

I'll post those images soon, but the point is you'll read that you need to be 90° to the sun for best use of a CPL, yet you don't even need sun to get best use of a CPL!

just use it accordingly.

[Tannin]

Relax. I'm OK. Allright, I admit I had a bad moment for a while there, but in the end it was just a shock and I'm recovering nicely.

Now, to business. There are three things I dislike about polarisers:

1. Keeping the damn things clean is impossible! Any filter can be a pain to keep clean, but CPLs seem to be the worst of the lot. I am always battling with the damn things.
2. I wish there was a twist setting for "no effect at all"! It's a pain putting them on and taking them off all the time, and you always wind up getting a dust splodge or a thumbprint on them as you do. (See 1.) Of course, this is impossible, but I still wish for it all the time.
3. I can't remember the third thing just at the moment.

(Actually, Arthur and I agree quite often, we just pretend to argue. And having Arthur around saves me having to write fair and balanced answers: I can happily just post one side of a question, safe in the knowledge that Arthur will be along soon enough to provide the necessary counterbalance. This makes life nice and simple. )

[ricktas]

The third thing Tony, would be leaving it on, forgetting it is on, and taking photos that end up with dark blue sky on one side and light blue sky on the other!

[Tannin]

Ahh, no, that would be #4, Rick. But you've reminded me of #3, which is the light loss. Because I have so much bird gear to carry around, I mostly have to battle along hand-held for my landscapes (it's just not practical to carry two tripods on my back, and the big birding tripod & head arrangement isn't really suitable for landscapes), and that lost light is often just enough to take me out of my comfort zone for hand-held landscapes. I have to open up te lens more than I'd like, or push the ISO higher than I want to, or use too slow a shutter speed and hope to get away with it.

And that remimds me of number .. er .. 5: if you carry two bodies for landscaping (as I do), one with a normal lens and the other with a UWA, and you've gone to the trouble of making sure they both have 77mm threads so that you can use the CPL on either one, it is always on the wrong damn lens! You want a wide-angle shot with CPL and it's on the 24-105. Or you want to use about 60mm with no polariser and it's still on the 24-105. But the moment you want to shoot at 12mm bare lens, the damn thing has magically attached itself to the 10-22!

[arthurking83]

LOL! and they're too damn expensive to just keep buying one for each and every lens.

I wish someone would make a quick clip on version one day.
My 500mm mirror lens has a screw on cap. It's probably the single most annoying reason as to why I hardly ever use it!

I have the which lens has the CPL issue with my two tammys both of which have 67mm CPL's and they are the lenses with which I generally have that issue.. but the 10-20mm has a 77mm filter, and my only other 77mm filter threaded lens is the 70-200mm which barely sees CPL use.. so it stays on the Sigma 99.9% of the time.

yes they are a pain to have to share between lenses!

[David]

Thanks people for the intereresting and funny responses.

Today I wandered into Photo Continental intending to buy an ND screw on filter for my kit lenses and another for the Siggy wide angle lens I am test driving over my trip to Tassie next week (along with some Canon lens caps because Im always losing them)....

What I ended up with (and Im going to blame the very attractive female assistant with way too many buttons undone for this) was an ND filter BUT no square attachment thing because she had no 77mm size ones in stock. I convinced myself that I could use just the ND glass (hand held in front of the lens) for both the siggy wide angle lens and my crappy 58MM kit lenses because I always use a tripod and I have a remote so I can set up the shot....then use the left hand to put the ND in front of the lens and the right to click the remote.... and I DIDNT get an ND screw on for the kit lenses. But after thinking about it the slower shutter speed it affords will require me to keep my hand/filter still for sometimes LONG exposures

Her bad was that she gave me an O.3 which is only a 1 STOP ND and I asked for a 2 STOP one (0.6 i think).... so she screwed that up.


I will use the CP for reflections reduction and play with it as advised by people here, when I want to reduce the refections in waterholes/shorelines/lakes/caves to get the below surface detail- A CP can also enhance colour saturation which no other filter can do.

I will use the ND for bright light conditions, reducing light intensity and situations where I want a slower shutter speed or wider apeture (waterfalls, cloudless days).

My crappy kit lenses give an 18mm-55mm and 75mm-200m range but to be honest I will not be taking the 75-300mm beyong 100mm because the further out you stretch these crappy kit lenses the less DOF and sharpness you get and the 18mm-55mm crappy kit lens is equally as poor beyond 35mm so --- so dump em both and go with the Sigma wide angle lens bucko because its range is much better and the results wont be compromised by the focal length you ask it to give you.


See what happens when you try to be clever and improve your kit .. you end up buying something you are going to get frustrated/bored with very quickly, don't buy the screw on ND that would have served your kit lenses as well as the CP had done for you despite you lucky dip approach before you asked someone how a CP works and you remain committed to the test drive on a Sigma wide angle lens all the 'serious' photographers you talk to say is THE lens to get initially to improve on the landscape work I do.

Hmmm, I am going to keep the 1 STOP ND Glass I got yesterday and use it for the Sigma wide angle lens I am test driving and I am going back to Photo Continental and to buy a 58mm screw on ND filter to use on my kit lenses.

I think I will keep the Sigma lens (and ND gLass in front) for wide angle landscape shots such as mountain views, lakes and lookout type shots like Devils Gullet, Alum Falls, Dove Lake, Mount Wellington and use my 'ole faithful' kit lenses for other shots like waterfalls, seascapes, caves and rivers.

What I DO KNOW IS : Never to combine an ND with CP Filter: CP filters are pretty ineffective on bright, sunny days without cloud, almost as bad as shooting with no filter and the ND filter cuts out light and that is not always a good thing.



Thoughts, comments, observations welcome (I think I will get to my first 50 posts quickly at this rate, lol)

David

[arthurking83]

.....

What I ended up with (and Im going to blame the very attractive female assistant with way too many buttons undone for this) was an ND filter BUT no square attachment thing because she had no 77mm size ones in stock. I convinced myself that I could use just the ND glass (hand held in front of the lens) for both the siggy wide angle lens and my crappy 58MM kit lenses because I always use a tripod and I have a remote so I can set up the shot....then use the left hand to put the ND in front of the lens and the right to click the remote.... and I DIDNT get an ND screw on for the kit lenses. But after thinking about it the slower shutter speed it affords will require me to keep my hand/filter still for sometimes LONG exposures

Her bad was that she gave me an O.3 which is only a 1 STOP ND and I asked for a 2 STOP one (0.6 i think).... so she screwed that up. ....

I can totally sympathise with the effectiveness of the assistants sales pitch!

As for the ND and long shutter speeds, you may have to do several attempts to 'get it right'.
It's hard holding a filter against a lens at long exposures.(camera shake as you mentioned).
I've done a lot, and my last few images form Warnambool all were done with handheld GND's AND a CPL, I can't remember the shutter speeds off the top of my head but they were 1/6 or so. I can't imagine excellent results at like 1 sec or more, but as long as they are acceptable.

CPL use can be at any time of day, and it's effectiveness is going to be variable according to the conditions. No one single set of conditions is right or wrong for their use. Increasing color saturation is the most common use of CPL's.

Only a few minutes ago, I was mucking about in my Fluoro lit kitchen with the CPL on and off, and apart from 1 stop of light loss, the slight increase in tone range made using the CPL an advantage. It just cat the glare from the fluor light against the white shiny wall a little. A kitchen at night with fluoro lights!! who would have guessed huh?

Problem I see with CPL and ND stacked is vignetting especially on a UWA lens(personally I like natural vignetting anyhow!), and so much loss of light that you can't focus nor actually see anything! So you may have to compose and focus and then add the filters. Apart from that, there is no reason not to stack them.. I do regularly(but I use GND's not ND filters).

[Seabee]

What I DO KNOW IS : Never to combine an ND with CP Filter: CP filters are pretty ineffective on bright, sunny days without cloud, almost as bad as shooting with no filter and the ND filter cuts out light and that is not always a good thing.

Oooooops no-one told me that, lol
I do that combination all the time and it seems to work for me.
I actually used that combo on my McKenzies Fall thread. (landscapes)
The Polariser to cut some glare off the wet rocks and give back some warmth (the brown tones in the rock) without the CP they ended up glaring white highlights.
Plus the ND to allow a longer exposure,\.

Well thats my method and reasoning anyway,

Cheers
Cindy

[arthurking83]

....

Well thats my method and reasoning anyway,

Cheers
Cindy

good enough reasoning for me.

I think experimentation is the key here too.

what works for some of us doesn't for others, and it's all a matter of taste and need for a specific situation.

good to hear Cindy!!

[David]

Tested four options today in bright sunlight at home with the lens and ND filter coming out on top for sharpness and least glare/burnout ..1. No filter. 2. CP filter only 3. CP and ND and 4. ND filter-

The reason I did this was to get some idea of the best combination to use between 9-4pm in the daytime in conditions where there is a clear sky and bright sun-just in case Tasmania offers that up next week.

IF the conditions are overcast and offer plenty of cloud cover I am going to have to push the sky into a background role between 9-4pm because sunrise is going to be at around 7am and sunset at around 5pm. I am hoping Qld coughs up a cloudy, overcast day so I can test the four combinations at home in those conditions too.

I have read of people combining CP and ND filters with success but most 'experts' reckon it is a no no because..(cant remember) and I found the combination makes the result way too dark so I would have to bracket down a stop after asking the camera what it reckons is the correct exposure point.

Bottom line from all of this for me from this thread is that there is no absolutely wrong way or right way to use filters, so experimentation and discovering what is going to work for me in terms of my current equiptment, the effect I want, the compromises I will have to make and failures I will have to endure are all good for photography experience based wisdom - bahhh.

This 'difficult pleasure' is getting more complex - the more I learn the more I realise i dont know much and the more I try to understand the less confident I get about having any clue about what makes for good technique and what does not.

Meantime, the much more sensible Mrs Bagabun quietly reminded me that this is supposed to be a holiday trip, that the places I am going to see are going to be a great personal pleasure on their own with or without a camera in my hand and I started this photography hobby to enjoy the bush and rainforests and waterfalls and creekbeds and nature (basically) at is most beautiful and challenging. What happened to that ? says she.

Whats more, says she, is that in fact I have been able to come home with some pretty damned good photographs of wonderful places captured in magical moments- she says my passion for nature and awe at the visual pleasures nature provides will alway drive me to find and photograph wonderful places and scenes - says I have a innate instinct for it-

Ah the wiser head of reason from an artist who knows about passion and beauty and the drive to explore it and want to see it and replicate it. I love my Mrs, she always knows when to tell me to get over myself, take a much more relaxed view and trust myself to develop my photography over time, not in less than a year, HA she says, took her that long to find out how to use a colour wheel properly, lol.

So I WILL take my camera to Tassie, will take the kit lenses and Siggy wide angle and the CP and ND filters and see what happens by absorbing myself in the feel and mood and moment I want to convey in my images ( a reflection of what I am actually feeling at the time I see that waterfall for the first time or watch the sunset creek across the sky at Mt Wellington) and if I screw up every single image it dosent really matter because there is no sense in turning into a parnoid technical photographer and make pretty shots that have no heart or passion or luck or accidental or flaw or imperfection in them... that is not nature and that is not me either... i hate fake, conjured, prefabricated, pre planned, polished, perfect anything.... so why the heck am I thinking that way with photography ?

I WILL ditch 95 percent of what I shoot but who cares, Im supposed to be having fun

Apologies to those who actually read this - i think it has some value because it reflects the thoughts and struggles of alot of would be amateur photographers who often forget what they took up photography for in the first place. Meantime Bagubun will desist from these rants and be more appropriate in his postings Ricktas, promise.

[ricktas]

What I DO KNOW IS : Never to combine an ND with CP Filter: CP filters are pretty ineffective on bright, sunny days without cloud, almost as bad as shooting with no filter and the ND filter cuts out light and that is not always a good thing.

Oooooops no-one told me that, lol
I do that combination all the time and it seems to work for me.
I actually used that combo on my McKenzies Fall thread. (landscapes)
The Polariser to cut some glare off the wet rocks and give back some warmth (the brown tones in the rock) without the CP they ended up glaring white highlights.
Plus the ND to allow a longer exposure,\.

Well thats my method and reasoning anyway,

Cheers
Cindy

I have used a CPL and ND/ ND grads together as well. Got the results I wanted at the time, so will do so again.

[ricktas]

.. Bagubun will desist from these rants and be more appropriate in his postings Ricktas, promise.

Don't make promises you can't keep!! Besides it was a good read. Hello Mrs Bagabun!

[Seabee]

It's all about learning..............we learn because we enjoy.
We get antsy when we try to run before walking.

My Philosophy has always been "if you are not being paid for it, then relax and enjoy the mistakes you make"

Equipment does not make the Photographer...............Passion does.
Enjoy your holiday

cindy