Polarising Filter Question:::

[Dan Gamble]

Hi all,

I just got myself a HOYA CIR-PL (If that matters) polarising filter to go on both my 18-55mm IS and the 55-250mm IS lenses and I have some questions.

A) The lens (head? Barrel) rotates (and I knew this) so what's the best way to know which point of rotation I need to adjust the filter after I've found focus? (I thought I'd get a little book with the filter telling me this stuff)

B) Is there a good way to ensure I can safely adjust the rotation of the filter without bumping my zoom and focus out? (especially focus given it's directly attached to the front of the lens)

C) Is there only one angle (flat) that I can use it or can I play with different rotations? What difference would it make?

I know it seems that I am asking many questions that I should have asked before getting it but it was bought on impulse when I could see some marks on my lens (I bought a cleaning kit too) and I had read here that they are also a very good method of lens protection.

Any info is much appreciated. :o

[dbax]

Dan, whack the things on the lenses, they will have different effects at different times of the day, dependant on the angle of the sun, its a learning thing (play time for grown ups- though I can think of some better options)I tend to focus, adjust filter and re focus( though not always). trial and error... but its not rocket science.
Its digital so its free try what ever you like , its all learning. enjoy:D:D

[Dan Gamble]

Thanks for the quick response and... Excellent advice David.

That actually makes me feel a whole lot better. Yeah! Of course! Just do it!!!

Cheers!!! :D

[gerry]

A) there is a dot on the rotating portion of the filter, rotate that towards the position of teh sun for maximum effect of the polarisation..

B) practice i guess, I have a hoya and it takes a bit of time to become used to teh position o fteh filter and adjusting, especially if you have a lens hood on.

C) are to talking about different angles of the filter to the lens element, ie without the filter attached, not sure, experiment?

CPL's are great, they essentially do one thing, remove reflected light from a scene when orientated correctly, this has teh secondary effect of increasing colour saturation, it also knocks out a bit of light getting into the lens.

Try it on water scenes, landscapes and the like - good luck.

[arthurking83]

I had a lens once(Sigma 70-300) that rotated as it focused too.

All I did was to hold the rim of the CPL as I focused in AF mode. Works well enough.

[DND]

I got one a few days ago and what I did was find some water with reflections on it and turn the filter untill the was no reflection,
I don't know if this is right, I have ever used one before

here is one lesson I know is right, Don't do what I done the first day at the reptile park. I was leaning over the red belly black snakes encloser and adjusting the filter instead of turning the outer ring I was turning the whole thing and it unscrewed and fell in with the snakes!!... lol

So I learn't to make sure the filter is tight

heres a couple of shots when I was playing around with the filter

[Dan Gamble]

Gerry, I can't see a dot but just the brand , model, size and country of manufacture. I was also referring to the angle of rotation of the filter relative to the horizon and now you have clarified the distinction that I should be considering the angle relative to the sun so thanks heaps... and for your other answers also.

So-far I've found it appears "flat" (I tested it on my LCD screen which is also polarised) when the labels are to the left. So that can be my "dot". hehe!

Thanks also to you Arthur. Will be a good method once I've found the position where I like it. :)

[Dan Gamble]

here is one lesson I know is right, Don't do what I done the first day at the reptile park. I was leaning over the red belly black snakes encloser and adjusting the filter instead of turning the outer ring I was turning the whole thing and it unscrewed and fell in with the snakes!!... lol

So I learn't to make sure the filter is tight

Wow there's a big difference between the two. Does the second one seem a little washed out on the right though? The colours seem a little bit too... Or is that because the exposure will change with the angle of the filter??? Hmmm...

Thanks a lot for showing me your examples. I am also very sorry for your loss.

[David]

There is an optimum effect point when you are using a CPL on the front of the lens, which is 90 degrees from the sun. That is, the sun is ideally aiming itself at your right or left shoulder.

IF you have the sun right in front of you or behind you when u take a shot it will provide very little if any use to the shot, so I do not have the CPL attached in those situations.

To take most of the guess work out of positioning the CPL to get maximum effect I use a method that is clunky to begin with but becomes second nature when you have done it a few times.

1. Paint a white line on the edge of the CPL with something (I used white out).

2. Screw the CPL on to the lens but not too tight : for some reasons CPLs I have used like to get stuck with the lens or other filters (Neutral Density) if you screw them on together too much. I leave a little bit of give space there- makes it easier to remove later.

3. Set up my shot composition and exposure wise, pretty much ready to go.

4. Set the white point of the CPL at the top of the lens with the camera in manual mode and make sure the 2..1..0..1..2 mark I am looking at is right on the 0.

5. Rotate the CPL a quarter of a turn or half of that and see if that asks for a slower shutter speed. It will shift the mark on the 2...1...0...1...2 to the left of the zero or the right. Sometimes the shift can be only 1/3rd or 2/3rds of a stop so you have to watch that carefully.

If it shifts to the right of the ...0... the CPL is at its least effective (it is asking for less shutter time so the effect is nullified. If it shifts to the left of the 0 you are getting to best use of the CPL because it is at that point asking for more shutter speed and that means it going to take longer to take the shot because it needs more light (yay, the CPL is actually doing something).

In any case, as you rotate the CPL on the lens, the camera will ask for more or less shutter speed. The point that asks for the most shutter speed (working in Manual Mode) is going to be to optimum point for effective impact of your CPL.

5.When I have found that optimum point, assuming you are using a rotating lens when it focuses and have the camera attached to a tripod, I do what I think Arthur suggested. I hold the edges of the turning part of the CPL (not the whole thing) with my left hand, adjust the exposure back to the 0 point, let the camera autofocus for me, then take the shot.

Apart from that, practice it and use the CPL in all contexts involving water and reflections to good use and experiment- 2 years of playing with CPLs and I am still have more to learn.

[OzzieTraveller]

G'day Dan

Well you've asked an excellent Q and received 1/2 dozen very good answers - and here's another one
As my cameras use electronic viewfinders, I experience several things that dSLRs dont ever, ever see :D ... and sometimes it's magic, sometimes itz a buga

In this case the EVF is too smart for its own good - as the pola filter starts to darken the image, the EVF lightens it up again to compensate - ie no good at all
To overcome this - and this is my suggestion for you as well ...


on a strip of masking tape, at 1cm intervals I wrote "A B C D E etc etc" till Z,
then carefully razor-bladed its width to that of the pola filter, then wrapped it around the filter
to use it, I rotate by hand to see the actual effect I'm after, note the Alpha letter at the top-centre,
screw onto the lens and align the letter to the centre of the lens

Sounds a bit whacky, but it's easy & qwik

Hope this helps a bit ...
Regards, Phil

[Dan Gamble]

I greatly appreciate everyone's responses....

The sun's out today. Will be taking my new filter out for a play at lunch me thinks.

Gotta say. I love how photography is so personal and everyone, whilst sharing similar approaches and theories, will have their own little way of doing things.

Thanks for sharing your little ways. :)

[exwintech]

Phil - Thanks - that strip of tape is a great idea! I have the Hoya PL-CIR Polariser, which I'm using with Canon SX10 (Lensmate adaptor), and Fuji HS10, which is threaded for 58mm filters. This filter has no "aligning" marks - which means it's not saying "where it is" once you see where the effects are. The tape idea will be a big help with that!

In a bundle of old Pentax gear I was given recently were several "colour" filters, a "Skylight" one, which just seems to be a front element protector, and a 58mm Polariser. This is marked 'Hoya 58mm PL Japan', and does have an alignment "white line" on the rotating ring.

Of course, it's a linear Polariser, and wouldn't work with a DSLR, but does with my SX10 / HS10 P&S devices. I use Manual with Polariser, and avoid having to lock-up in Aperture or Shutter.

When "stacked" and "off polarising" the two combine to drop several stops - maybe a bit like an ND filter. They also have a "cross-over" point which is very dark... I'm just trying to work out suitable experiments for these 2 effects.

That is - they're "doing things with the light" - so I might be able to use that somehow....? The SX10 goes to f/8, but the HS10 goes to f/11. Is there some workable combination there that I could use for 'silky water' or other effects?

I'm busy saving towards, now, a Pentax K-R - and ND filters seem to have 'interesting' prices...

Regards, Dave.

[OzzieTraveller]

G'day Dave

I have tried 2x pola filters before to become an ND-16 - it certainly did a good job of diminishing the qty of light, but ...
it also turned the colours to a bright magenta

I will be very interested to see if any of your experiments do the same :-)

Regards, Phil

[Willraja]

Cross polarising with 2 PL filters can produce a psuedo infrared filter. Polarising filters are designed to work best in the visible light spectrum with the effects of the filter tailing off past red and blue light. There is still some polarising going on in the infrared spectrum so if you add a PL and an IR filter togethor you will see a difference to straight IR, but it is more limited. The shift to a bright magenta would seem to confirm that you are indeed picking up more IR light than visible light over a long exposure than standard.

[old dog]

a question from me.....I just got a hoya pro 1 cpl for my 77mm lenses and tested it out re correct position for maximum polariation. It happens to be the same as my hoya 67mm filter......looking at the front glass, both filters have the join (like a circlip sort of, that holds the glass into the filter frame) top and bottom......so I just align the joins in the vertical position....and it works..........so my question is.....what happens when I turn the camera and use it in portrait orientation. Does the cpl work still, to it`s maximum effect, if I align the joins sideways (horizontal position) before I rotate camera to portrait position......hmmm. I suppose I`ll have to experiment to find out.

[exwintech]

Phil - You get a Magenta tint with 2 x polarisers? That's neat - I can only get a spooky Blue...!

Did you use 2 x Circular Polarisers to get Magenta?

I used a current era - few weeks old - Hoya Circular, and a classic era, about 1972 (guessing on the Spotmatic F it came with) - Hoya Linear.

This try was mid afternoon, sun down enough to be reflecting directly from a truck parked across the street from my kitchen window. Trying to get a direct shot of the truck without filters was just blowing out.

The first image with filter crossover shows an almost "moonlight" effect - the second is with filters off-effect.

Quite entertaining, such experiments - even if I have no idea what I should be doing....! :D

Dave.

[OzzieTraveller]

G'day Dave & Graeme

Graeme - can't comment upon the clips holding the filter together ... so your alignment may/maynot be a worker :confused013
But, the 'top' of the filter must always be at the 'top' of the frame ... so if you rotate 90degrees from landscape to portrait you will need to realign the filter by 90degrees to bring the top back to 'top'

Dave - like your moonlight blues ... here's my magenta pic
[shot late afternoon, trying for long exposures to show movement]
http://i53.tinypic.com/33k53cl.jpg

Hope this helps ...
Regards,Phil

[exwintech]

Phil - I do rather like that - looks like billowing Pink Candy-Floss at the Show...!

Mine might have oddly-amusing effects - if I can find a nice old overgrown graveyard... :rolleyes:

Don't think I'll want to stack those 2 Circular and Linear Polarisers for std photos, though.

Using just the Circular, it seems to give 1-2 stops down with the HS10 - depending on amount of zoom used. About 1 or under at the wide end - 2 or more at the long end. At 25-30x zoom its light-gathering abilities drop considerably anyway.

Unless in very bright light, over 24x or so the AF "hunts around" like a Foxie-on-steroids...! Anyway, over 24x - while the camera has shake-reduction, I don't (and with diabetes, can't drink enough to fix that... )

So the HS10 goes onto the Slick F740 I bought it (no car, so had to get one that fits in a carry-bag) - and then, in Manual Mode and Manual Focus - I can firmly insist that it does what it's told to. At times, it even obeys and takes photos...

While not everyone would buy a Fuji HS10 for its "DSLR-like" photographic functions (Fuji's Advertising Department must be on some very interesting stimulants!) - I can highly recommend it for its Entertainment Abilities...

With the Fuji HS10 safely restricted to its tripod - users should keep their Canon SX10 ready around their necks, for any photo opportunities that might arise.... ;)

Well - that's more a dig at all the Review Sites that have been bucketing the HS10 - with a bit of firm persuasion, it does actually work quite well.

For example - and getting back to Water-etc shots - the HS10 does go past the f/8 limit of most P&S devices, to f/9-10-11. At 30x zoom and at f/11 - one can only be glad Fuji gives it a full 2EV Exposure Compensation.

So, using that the other way around - I'm thinking maybe part-zoom, f/11, and the Circular Polariser in non-polarising mode, to get enough stop-down for water-effects. Is that the right way to work that out? Or there's a better way to do it? Without paying a 1/4-K-R's worth for proper ND filters?

Do the folk who work hard enought to afford the $3,000.00 bodies and $4,000.00 lenses actually have as much fun as I'm having "on-the-cheap"? I sure hope they do!

Regards, Dave.

[OzzieTraveller]

G'day Dave

me thinx you are having a bitt-ova-dig at our dSLR mates :-)

Keeping this thread to pola filters ... the pola filters are excellent at reducing reflections esp on water & glass, very much less so on metal and almost-not-at-all from painted metal surfaces

Here on AP you will find lots of stuff on ND filters, incl a magic one called the "ND-1000" that many of us use for very-very long exposures.

ps: & btw - I like the hs10 too
Regards, Phil

[exwintech]

Phil - No, wasn't being sarky - I have every admiration for those who work hard, and from that, can afford things they like. I spent nearly a quarter-century as a truckie, 16 years of that on the interstate, then 11 years - Win-3x to the early years of XP, as a Windows Tech... That's what the "exwintech" is about. (It's also why I now use Linux, but that's another story...) So I have been on quite reasonable income, and also had plenty of nice things I liked.

The comment was rather on me - I've adjusted to being on a fairly low fixed income - and getting into photography has been a new and different interest. And I'm having a lot of fun, starting from a zero-base of knowhow - learning how to do things.

I did "nearly" buy a Pentax K-X instead of the HS10 - but felt I didn't yet know enough, so went with the HS10 instead. The new Pentax K-R is now my savings target. If I don't find a low actuations K20D with 30-90 days Shop Warranty before that, maybe...

PS: - Just found I can't delete the comment you mentioned, above. Perhaps the Mods can remove it, if it's offensive. That wasn't intended.

Regards, Dave.

[old dog]

phil....thanks for the explanation. What I also meant.....the back glass needs to line up correctly with the front glass to work properly...correct. If so if I turn the front glass so that the top in landscape style is turned to the top in portrait style...then both glass elements are in a different position to each other...unlike in landscape position. Do I make sense? I guess I don`t really know how the glass at the rear works......hmmm. Maybe someone can explain.

[Dan Gamble]

looking at the front glass, both filters have the join (like a circlip sort of, that holds the glass into the filter frame) top and bottom......so I just align the joins in the vertical position....and it works..........

I don't think it's a seam. I think it's our "DOT as it were. Just noticed it on mine yesterday. :pirsmile:

So, you discovered that it needs to be angled to the axis of the suns direction? That'd make sense too.

Nice!!

[old dog]

I think I will have to experiment a bit to find things out in portrait position.

[Dan Gamble]

I think I will have to experiment a bit to find things out in portrait position.

What makes portrait different to landscape orientation?

[old dog]

I just assumed that the rear glass must be in a certain position for the front glass to correspond in it`s certain position (optimal polarisation) so I guess that when you turn the camera into portrait position all you have to do is take the shot....if it`s already optimised in the landscape position. Does that make sense?

[Dan Gamble]

I just assumed that the rear glass must be in a certain position for the front glass to correspond in it`s certain position (optimal polarisation) so I guess that when you turn the camera into portrait position all you have to do is take the shot....if it`s already optimised in the landscape position. Does that make sense?

I'd would have thought you'd just rotate the filter 90deg's opposite to the angle the camera rotated when going from Landscape to Portrait. ie. putting it back where you had it set to in the first place for optimum effect.

Or does it also depend on the censor with DSLR as to which is the best angle of rotation?

(EDIT: Still waiting for an chance to try mine out. damn you daytime work hours!!!) :)

[old dog]

haaaa......I`m going to experiment tomorrow. I`ll report my findings in this thread asap. Got to work this out as I`m off to Turkey for a holiday next wednesday and I`ve got to get my pics right...:th3:

[OzzieTraveller]

G'day Dave & Dan + others

Gosh - the things I find from this forum...
Dave - I also was MCSE certified back in w-3x & w-95 days tho I let it all lapse as I moved on

Dan - you're quite right in the presumption that IF the camera is rotated 90deg from landscape to portrait mode, the filter has to be counter-rotated back 90deg to where it started from to realign it to the sunlight for its best results

As to the alignment of each filter when using two filters - I can't help here ... I was mucking around to try for a ND4 + ND4 effect, so I was just twirling them to get maximum 'blackness' so that I could then get swirling waves over the rocks

As an aside here ...
There is a photo doing the rounds of the advertisers/magazines, showing a blue car, probably a '60s US convertable with aeroplane-like fins at the rear, where the text claims to have removed all reflections from the paintwork via a pola filter.
The picture is - in my opinion - a total fraud

From the days when I was doing my photography stuff at RMIT in Melb, we studied optics & pola filters in some depth - and unless the laws of physics & light have changed with the introduction of digital cameras, there is no way known to mankind where those reflections could just magically disappear. I can think of how 'someone else' could do it, but not via a pola filter on-the-camera

Regards, Phil

[arthurking83]

....
As an aside here ...
There is a photo doing the rounds of the advertisers/magazines, showing a blue car, probably a '60s US convertable with aeroplane-like fins at the rear, where the text claims to have removed all reflections from the paintwork via a pola filter.
The picture is - in my opinion - a total fraud

From the days when I was doing my photography stuff at RMIT in Melb, we studied optics & pola filters in some depth - and unless the laws of physics & light have changed with the introduction of digital cameras, there is no way known to mankind where those reflections could just magically disappear. I can think of how 'someone else' could do it, but not via a pola filter on-the-camera

Regards, Phil

It totally depends on the shade of blue Phil!!

Darker shades with brighter background reflections can be almost totally eliminated by the Pol.

If it weren't for the polariser, these images would be self portraits!

http://www.ausphotography.net.au/gallery/files/1/0/dsf_8431.jpg

http://www.ausphotography.net.au/gallery/files/1/0/dsf_8429.jpg

yes, you can see some reflection, but I can assure you without the polariser it'd be all reflection. A bright sunny day(on the odd occasion) where the reflected subject matter was well lit, and so was all to prevalent in the paintwork.

I also got a few shots of a black Ford Thunderbird('55-ish, I think). I'm crouching fairly low down and close to the front of the vehicle, and my ugly mug was very prominent in the reflection in the paint work. Pol removed me completely without the need to install PS/CS!! ;)
I didn't process or upload that image, but I can if you wannna have a peek.

The efficiency of reflection minimisation is dependent on many factors, but it can be 100% effective in some instances.

[exwintech]

Arthurking83 - Gee, do like those effects! Particularly the "deeply-depth" in the second one.

How was that done - if it isn't a "trade-secret"? Special lens - or something in PP...?

And yes - do let us see the '55 T-Bird - they're Icons of their Era - please....

Dave.

[OzzieTraveller]

Thankyou Arthur

Your images "reflect" mine too
However, the offending advert claimed that a pola filter would remove reflections, and in the advert's image, not a single reflection of any sort was visible

Regards, Phil

[arthurking83]

....and in the advert's image, not a single reflection of any sort was visible

Regards, Phil

It should remove close to 90% of a very bright reflection, where subsequent and very basic pp in the form of brightness reduction should(could) completely remove the remaining 10%.

In my non uploaded T-bird shot.. not uploaded due to pretty ordinary image quality!! :o .. the reflection of myself in the front guard was totally eliminated without any PP at all, simply in using the polariser. I was hunched down low and in some shadow, and there is no reflection at all in the black paintwork(where there would have been without using the polariser)

Harves' (old)polariser thread clearly demonstrates how effective a polariser can be against reflection, I've seen in other instances 100%(or close enough to it) removal of reflections in other instances too. Adverts and their grandiose claims of miraculous magic will be worded such that they maximise their marketing advantage!! ;)
Totally eliminate reflections by using a/our/their polariser filter, but only under specific conditions .... which doesn't sound as amazing when compared to totally eliminate reflections using our polariser filter!.

I'll try to upload that T-bird image to display how effective they can be tho.

[sunny6teen]

apart from remembering where the sun is, don't get too bogged down about cpl's. just turn the thing until you get the desired effect in your viewfinder

[arthurking83]

For landscapes with big blue skies.. that is generally what I do too.

Sometimes(and almost all the time!!) when polarising a vast blue sky using an ultra wide angle lens, depending on the time of day, time of year... etc you can get those 'ugly' dark patches in the sky where only a small portion of the huge field of view is darkened. In these cases, I sometimes only partially polarise ... so that maybe one corner of the sky will darken(you can clearly see the darkening effect across the sky through the viewfinder!), I'll adjust making sure that if I need to reduce glare in other parts of the image, that I'm polarising efficiently.. and not just at random... and then handhold a GND and an angle, to compensate for the other section of the sky not being polarised.