Polarizing Filter

[Steve's Girl]

Uhhh.... so in circular polarizer for idiots language, what is the practical answer here? If you do need to rotate the thing, how and how much?

Thanks!

 

[Code]

Short answer is that circular polarizers work exactly the same as linear polarizers, they just don't mess up SLR metering & AF. So yes, they must be rotated based on the position of the sun to achieve the desired effect.

 

[fortheluvofpooh]

do you leave this on your lens all the time? Or is it just for taking photos through glass, ice things like that. TIA.

 

[Golf4food]

No, it only does any good when you have a 90 degree angle to the sun (early morning or late afternoon if you are facing north or south (won't do much facing east or west then) or around high noon when the sun is directly overhead (you can face any direction then because it is all 90 degrees) or want to reduce glare. Any other time you might as well take it off since it can reduce the amount of light your lens allows in and thus make it seem "slower".

 

[fhirleighinn]

I leave mine on when the son is out about 90% of the time, and only about 25% of the time at night. It can be useful if you want less light in order to take a longer exposure.

 

[DueyDooDah]

I leave mine on most of the time for two reasons: 1) Lens protection; 2) I'm lazy

I take it off during evening/late hours and early morning if I need an additional stop.

 

[DVC Jen]

I only use mine when it is needed.

 

[pjacobi]

No, it only does any good when you have a 90 degree angle to the sun

That is incorrect. The polarizer has its MAXIMUM effect when you have a 90 degree angle to the sun. It is still useful at any time of the day, although the effect is not at the maximum. However, most of the time you don't want maximum polarization because it can turn the sky a false deep blue/purple color. Each scene requires the polarizer to be carefully adjusted to achieve the desired amount of polarization. This requires some skill.

A polarizer can also be used to remove reflections from glass or water which can be done at any time of day. This effect cannot be duplicated in post processing.

I usually put on a polarizer any time the sky might be in the picture.


-Paul

 

[fortheluvofpooh]

thank you all for your tips.

 

[BuzzLiteyear]

or around high noon when the sun is directly overhead (you can face any direction then because it is all 90 degrees) .

Just a point of clarification...there is no place in the continental United States where the sun is ever directly overhead. Southern Florida (the keys) come very close, but all locations in the US (mainland) are above the Tropic of Cancer.

 

[jann1033]

That is incorrect. The polarizer has its MAXIMUM effect when you have a 90 degree angle to the sun. It is still useful at any time of the day, although the effect is not at the maximum. However, most of the time you don't want maximum polarization because it can turn the sky a false deep blue/purple color. Each scene requires the polarizer to be carefully adjusted to achieve the desired amount of polarization. This requires some skill.

A polarizer can also be used to remove reflections from glass or water which can be done at any time of day. This effect cannot be duplicated in post processing.

I usually put on a polarizer any time the sky might be in the picture.


-Paul

i guess since my area the sky is usually overcast( really like 350+ days of the yr) this had never happened to me but last week it made my skys just like that i was in the pier in lake erie on a really bright day around 2:30-3:00...looked really odd even though i could lighten them up in pp it was a pain . usually i use it as needed since my lenses aren't that fast i can usually use the extra light unless i need a good sky. and i figured out that was why the photo i posted in the what to change tread wasn't very contrasty..the sun was maybe 45 degrees from me...amazing how much it changes due to the angle.

 

[Golf4food]

Just a point of clarification...there is no place in the continental United States where the sun is ever directly overhead. Southern Florida (the keys) come very close, but all locations in the US (mainland) are above the Tropic of Cancer.

Of course not. But close enough to get use out of it.

 

[handicap18]

I only use a CP when I think its needed. I don't leave any filters on my lenses all the time. I used UV filters all the time years ago, but felt that it degraded the image a little. I didn't think my images were as sharp as the could be. When i took the UV filter off, things looked better. Maybe it was just a cheep filter. ??

 

[Experiment_626]

I have long read and heard the stipulation that with autofocus cameras, one had to use a circular polarizer as opposed to the older, linear polarizer. I always presumed the reason for this was that autofocus works by resolving contrast, and that the tiny lines in linear polarizer would confuse the autofocus mechanism. Then, not too long ago, I read something that seemed to give a totally different reason -- and naturally, I can't remember what that reason was.

Does anyone know why we need circular polarizers these days?

SSB

 

[Code]

Cut-and-pasted from my reply on another thread about polarizers:

SLR cameras use polarizing beam splitters to split the light coming through the lens 3 ways.. viewfinder, metering sensor, and AF sensor. With a linear polarizer, you get a cross-polarizing effect in the beam splitters, and both metering and AF are fouled. A CP has an extra layer behind the polarizing layer that de-polarizes the light (though the image has already been changed by the polarizing layer) so there is no cross-polarization and the AF and metering work as they should.

 

[Morganw42]

I just bought a Nikkor 70-300 VR for our trip in Oct. I'm planning on using it at AK primarily and for outdoor wildlife photos in general. I know that the lens isn't terribly fast, so I'll be shooting in good light out doors. Should I use a polarizing filter? I've never used one before but I like the deeper blue skies and clearer water that sample pictures suggest the filters will deliver. Do polarizing filters make enough of a difference to merit the $50 price tag?

 

[Experiment_626]

I just bought a Nikkor 70-300 VR for our trip in Oct. I'm planning on using it at AK primarily and for outdoor wildlife photos in general. I know that the lens isn't terribly fast, so I'll be shooting in good light out doors. Should I use a polarizing filter? I've never used one before but I like the deeper blue skies and clearer water that sample pictures suggest the filters will deliver. Do polarizing filters make enough of a difference to merit the $50 price tag?

I'd want one if I were you, I think. You might not always use it, but a polarizer gives effects that cannot be replicated entirely in post-processing. When shooting wildlife, there will be some cases where you might not have time to adjust the polarizer before you need to trip the shutter. Still, you often get a pleasing effect, even so. Remember that you'll lose some light with it on, which will make your lens slower.

All in all, I like polarizers and enjoy using them when appropriate and practical. In addition to the obvious effects on skies, they can improve the appearance of glossy foliage on overcast days. You might not always want to use them to eliminate or reduce reflections in water, but you can always rotate it to improve the view in those cases as well, or remove it entirely.

SSB

 

[boBQuincy]

A polarizer can make almost any photo look better: reduced glare; increased saturation; reduced haze; it's all good! I leave mine on whenever there is enough light. I also use one with a P&S, it helps.

 

[My2Girls66]

This is the one I have for my 70-300mmVR. Great price, $30, and free ship from Amazon.
http://www.amazon.com/Tiffen-67CP-6...1?ie=UTF8&s=electronics&qid=1242569416&sr=8-1

 

[KarenAylwood]

I have my 18-55mm kit lens (I admit I don't use it much anymore), along with an 18-200mm lens, and will be getting the Canon EF 100mm f/2.8 macro lens within a few weeks (birthday present).

I'm looking at the possibility of a prime lens. I hate switching lenses out, and want to get the lens I'd be happiest with since I don't plan on buying another for a while (famous last words).

I'm looking at the following...

Canon 50mm f/1.8 ($115)
Canon 50mm f/1.4 ($400)
Sigma 30mm f/1.4 ($440)

I can save up and wait to get the more expensive lens if it really is far better and worth the extra money. Which would I end up liking the best and getting the most use out of?? I'd like something I could use to photograph friends and family- at home and at events like weddings, etc.


Second part... I have no filters but was looking at getting a star filter or a UV filter. Then I saw that there are polarising filters.... what's the difference between a UV filter and a polarising filter? Which is more useful for outdoor/ nature shots? If shooting outdoors, could I leave this filter on all the time? Could I leave this on the camera even indoors?

Thanks in advance!!