Filters, when and how

[tayl0124]

Okay as seen in my sig I have 2 filters, a ring style Polarizer( I believe that is what it is called) and a Skylight filter. When do or would I want to use these?? I have been told that with a dslr the only filter widely used is the polarizer. Thank you in advance for your answers.

[Frog]

Some use the skylight or uv filter as lens protection and many of us say it isn't necessary and that its only a lesser quality piece of glass in front of your good lens glass.
The polarizer is used to reduce glare. Put on a pair of polarized sunglasses and you'll see the effect which cannot be re-produced with editing. Used mostly to make skies bluer and put detail in clouds and to reduce glare off water.
A neutral density filter is also a good idea.

[Didache]

Further to frog's answer, the polariser is especially useful for landscapes and seascapes where the sun is very bright and there are some clouds. It has the effect of darkening the sky and making the clouds really pop. It is not something I use very often - but it does help to prevent the washed out looking images that you can get in the bright part of the day.

Mike

[readingr]

Polariser for landscapes, seascapes, and skiing. It enhances colour and contrast and stops glare from sea, water, or snow.

Some say that ND grads are useful for landscapes but this can be done using multiple exposures and then bringing them together in PP.

The Skylight I only use in dusty or raining conditions so that I only wipe the filter with a microfibre cloth rather than the lens. The rest of the time its in its case.

Roger R.

[tayl0124]

as far as the ring polarizer, how is it actually used?? does turning the ring make big changes in the picture??? Haven't been able to figure this thing out yet. Maybe it is just a cheap filter. Inherited it from grandpa.

[Singletracklovr]

as far as the ring polarizer, how is it actually used?? does turning the ring make big changes in the picture??? Haven't been able to figure this thing out yet. Maybe it is just a cheap filter. Inherited it from grandpa.

When looking thru the viewer rotate the PL filter and you should see the sky lighten and darken.

There is a good chance your grandpa's polarizer is a linear polarizer and will cause your pictures to be darker or under exposed.
Todays digital cameras mfg'ers recommend a circular polarizer.

[SmartWombat]

If it's an old polariser for film, then it may be a linear polariser (PL), not a circular polariser (PL-CIR). On a digital camera an old linear polariser could throw off the AF and metering.
What is the labelling on the filter ?

[Frog]

This site shows the effect of using one. http://www.cs.mtu.edu/~shene/DigiCam...polarizer.html
Probably other ones out there too.

[tayl0124]

SW, it is an albinar 52mm Polarizer

[danic]

Hold the filter up to the sky and rotate it. If it's a circular PL, you should see an effect. If not, it's linear.

[tayl0124]

danic, I haven't tried it outside, but I have tried to rotate it inside and it does get darker at certain positions.

[Singletracklovr]

Hold the filter up to the sky and rotate it. If it's a circular PL, you should see an effect. If not, it's linear.

I humbly disagree, I get more of a polarized effect with a linear polarizer vs a CPL.

[SmartWombat]

The visual effect of circular or linear is the same.

Does it say "Super Albinar P.L" and a filter measurement in mm on the side?
If so, then it is a polariser, linear.
For film cameras not digital.

[freygr]

The UV filter is useful up in the mountains (Elevation 5000 feet or more). As for the Polarizer Filter the only difference between the circular an linear is that with the circular has unpolarized light exiting the filter. Just try the Polarization filter on you camera as SOME cameras don't care but others have problems with the linear polarization filters. If you have problems you will need to purchase the correct filter for your camera.

[SmartWombat]

Depends if there is a beam splitter in the AF or AE mechanism.
That is usually susceptible to linear polarisation.

[tayl0124]

danic, I haven't tried it outside, but I have tried to rotate it inside and it does get darker at certain positions.

Apparently it only does that when I am looking at my lcd monitor through it. I should get up from the computer chair every once and a while I guess.

Smartwombat - it only says ALBINAR 52MM POLARIZER on it.

[another view]

If it doesn't say "circular" on it, it probably isn't.

The amount of effect you can get with a polarizer depends on what angle you are to the light. If you're at 90 degrees, you'll be able to get the maximum effect (not that more is always what you want). Go outside on a sunny day and look thru the polarizer in a direction that would be 90 degrees between what you're looking at and the sun (IOW if it's directly overhead, look at the horizon). Now rotate the filter and you should see the effect. You won't get this effect on a cloudy day, however you still might see the effect on something like a waterfall.

[readingr]

A picture is better than a thousand words or so they say

Try a pano I took with a polariser attached (Linear on a DSLR) This is a pano across almost 270 degrees. The two darkened areas of sky are at 90 degrees to the sun.

[danic]

I humbly disagree, I get more of a polarized effect with a linear polarizer vs a CPL.

I stand corrected

[freygr]

I humbly disagree, I get more of a polarized effect with a linear polarizer vs a CPL.

I have to completely disagree. All a CPL is a linear polarizer with a unpolarizing layer on the camera's side of the filter. If you get a poorly made CPL you will have contrast and other optical problems which may reduce the effect.