Circular Polariser Issue

[mikew09]

Just a question. About 6 months ago I purchased a kenko CP filter, suposible hig quality. When I first tried it out I am certain tht when I rotated the front filter I could see the shade of the polariser effect - such as the sky colour soften etc.

Have not had the filter on the rig since until today and for the luv of me I cannot see any CP effect when rotating the filter, looking at the shots taken you can see that the polariser had dampened the harsh ligh but there is clearly no difference from rotating the front of the filter. I double checked to ensure the glass was actually rotating etc etc.

Do CP filters go off so to speak - such as a glass coating fails or such. I have to say I am a bit peeved as I paid around a $100 for this filter and have never really utilised it, now it appears to be useless.

Mike

[arthurking83]

No! they don't go off.

They have limited effect in some situations.

if in doubt about it's usefulness, turn yourself between 45-90° to your current orientation and try again

generally you'll almost always see reflections, such as glare on water, reflections on glass.. etc disappear.
if its 'bright and sunny green foliage will turn more green, but that also depends on the actual foliage too. The dull pale green colour of gum leaves generally doesn't have as much an effect as shiny foliage does, as the shine on the shiny green foliage is what your reducing when in bright sunlight.
The more dull and paler green surface of gum leaves is less shiny. Its still there, and only a direct comparison 'between two images of gum leaves, where one is taken with a polariser and the other without, will show you the subtle differences in that situation.

[mikew09]

Hmm - thanks Arthurking83. I am a little confused - so what is the purpose of the filter ring rotating?

[arthurking83]

rotating the polariser is to allow the user to adjust the magnitude if the polarisation they want.

as just one example: if you use an UWA lens, and you simply rotate the filter to fully polarise the scene, at some times of the day, you may get a large dark V shaped area in the sky(as well as the other polarising effects it produces in other parts of the same scene).
This can be a good thing, say if you're in a valley with steep sided hills on either side and only want a V shaped dark patch in the sky! other times you may want to polarise from another direction. or you may want to use a different camera orientation.
If you use landscape orientation and get full polarisation effect once you;ve set the rotation of the polariser, if you subsequently turn the camera 90° and use portrait orientation, you need to rotate the polariser 90° to suit.
There is a small white mark to help with knowing where the polariser is having a more dramatic effect.
Note, that with that white mark, it works equally in two directions.. ie. it's equally effective 180° from where it's currently set.

[gerry]

rhere is a small white mark to help with knowing where the polariser is having a more dramatic effect.
Note, that with that white mark, it works equally in two directions.. .

Just remember to position that white dot towards the sun - that will ensure you are getting the maximum effect for the particular scene

[mikew09]

Now that makes sense to. Just another question from an absolute newb to CP filter, so full polarisation is when the marker is at the top - is tht right Arthur.
I just confused me a bit when I couldn't see any change in the view finder when rotating the filter. I assume with the maker at the top the level of polarisation is horizontal across the filter from top to bottom or have I got it worng?
Sorry mate, I am a bit slow on the uptake on this one. :-)

[mikew09]

I think I had better bolt the sucker on tomorrow and have a play.

[mikew09]

Hi Arthur, just read another thread on CP filters - with your info and the top up the penny has dropped. Thanks for your help mate, appreciated.

[mikew09]

Just remember to position that white dot towards the sun - that will ensure you are getting the maximum effect for the particular scene

Thanks Gerry, I get it now. I luv this site, thanks for the help troops.

Will be out tomorrow putting this into practice. To think the filter has just sat in my bag all this time and I have quite a few shots with blown out skies.

Thanks again,

Mike

[Precious10]

I've always loved my polarizer. It does take a moment to get the effect right. But once you do, it is outstanding. With these clear blue winter skies, I shall be using my filter madly this weekend at Noosa.

[flash]

the way I am led to believe is that these things work best when at 90 degrees to the sunlight, is this correct??

[Fantasyphoto]

the way I am led to believe is that these things work best when at 90 degrees to the sunlight, is this correct??

Indeed, 90 degrees is correct.... if the sun is pointing directly at either of your shoulders you will see the maximum effect.

[flash]

yep I gotta get me some of them!

[OzzieTraveller]

G'day Mike

Good on ya mate for asking the big Q
Yes -as mentioned above- the pola filter works to its maximum effect when the camera lens is pointing 90deg from the sun's rays ... if mid-summer-day (+ perfectly overhead) then any of 360 deg around the horizon will get it
However, mid-am or mid-pm - if you are pointing towards or away from the sun, the effect will be minimal ... but across the sun (and the shadows thrown also) then the filter will be at its max effectiveness

Away from the sun ie- reflections it's a different story - then you are rotating the filter to minimise whatever reflections are visible (shop windows, etc etc)
Regards, Phil

[mikew09]

Thanks for the great feed back. I will be out playing around with this new knowledge.

Phil - thanks for the details. There is much to this than I ever imagined.

On another topic, I went in my usual camera shop yesterday to buy a ND Grad set and holder and basically the girl had no idea what I was after - not to mention they only had 1 Cokin kit on the rack that wash the warm filter set. Looking at the website it is the lanscape kit tht I am after. This was very surprising, they are normally pretty good.

Thanks again for all the help.

[mikew09]

I am currently searching the forum for some info on Grad filters and mounts - once I get my head around what looks to be the best for me (landscape, sunrise, sunsets) will post to get your worthy opions :-).

[reaction]

maximum effect does not mean best. Different parts of the sky will be affected differently.

ND should be your next buy I think. GND is only useful if you ALWAYS take sunsets, etc. Depends on your style.

Get a single ND8, don't get those cokin kits, so messy.

[Tannin]

^ Must be a misunderstanding there somewhere, Mike.

ND filters are of very limited use. All they do is make the entire scene darker and thus lengthen your shutter speed. So there isn't much you can do with them except make those weird-looking milky waterfall shots, or other things of the same general nature. Off the top of my head, I can't think of a single worthwhile use for them (unless you count weird waterfalls and unnatural seascapes as worthwhile, which I don't), but doubtless there are one or two other uses that make more sense and have slipped my mind.

Grads, on the other hand (GNDs) are very useful indeed, and certainly not just for sunsets. Indeed, I have never yet used a grad for a sunset, though I doubtless will at some stage but, like most ofther landscape photographers, have used grads extensively at other times of day.

Use a GND any time you want to get over-brightness in the sky under control Any time you take a shot and you can't get the ground exposed right without blowing the sky out, and you can't get the sky exposed right without turning the ground black, a grad is the answer. Or GND - same thing),

I agree with Reaction that the Cokin kits are messy. But what's the alternative? If there is a non-messy way to deal with grads (or indeed CPLs), I've yet to hear of it.

I got a simple 3 filter & holder Cokin starter kit to begin with. It didn't cost much and works well. I need some stronger filters to add to it (too often I need to stack the filters to get enough effect) but it was a good way to start. I usually just hand-hold the filter slides, rather than muck about with the holder.

You will also need a better way of carrying them about than the Cokin-provided plastic hard cases. These are terrible - bulky, they rattle around inside, and worst of all, you can't tell which filter is in which case so you have to open all of them to get the one you want. But I haven't got around to organising something yet. Some sort of padded soft case, perhaps a single wallet to hold the whole set would be the go.

[Fantasyphoto]

......ND filters are of very limited use....... Off the top of my head, I can't think of a single worthwhile use for them (unless you count weird waterfalls and unnatural seascapes as worthwhile, which I don't), but doubtless there are one or two other uses that make more sense and have slipped my mind.......

As Tony says, straight ND's only have only a few uses but another couple are;
1/. Improving light reflections over rough water at night (wow - not)
2/. Reducing shutter speed from the maximum to allow shallower DOF on bright days. (but you can always use a polariser instead)

GND's are a totally different story and worth investigating.

[Tannin]

2/. Reducing shutter speed from the maximum to allow shallower DOF on bright days.

I forgot about that one. But then it doesn't really apply to me as I only have 1/8000th shutters these days, and don't have any fast primes. I do remember, just once or twice, meeting this problem. So - what? - once every couple of years? Not enough to worry about or me. But for others, yes, it could be a much more important thing. Especially, come to think of it, with a D3 or D700 and that 200 base ISO. Bright day on the beach, 85/1.4, 200 base ISO ... yeah, you'd need it then.