Filter Question

Newb question. I want to get a polarizing filter to shoot outdoors.

1). What happens if you use it for portraits indoors too?

2). What type would be appropriate for indoor portraits, even if just for protection?

Thanks in advance for your help.

If you use a polarizing filter indoors, you are unlikely to see any effect such as the darkening of the sky or cutting through reflections - which are the main purposes for using a polarizing filter.

You will be cutting available light by about two stops when you use the polarizing filter. For this reason, most folks don't leave a polarizing filter on their lens except when they want the creative effect it can produce.

In the studio, there is absolutely no reason I can think of to put any ordinary filter on your lens. You might want to use some sort of "special effects" filter such as a clear filter with a smear of grease in an oval shape to frame the subject, but that again is for a creative purpose.

Adding a UV filter for "protection" is just asking for problems with your images. If you take a photo with a strong light source in a position to shine on the lens' front element, a filter - with its two extra surfaces not designed into the lens - is likely to cause flare to some degree. You might see a "ghost" of light in the photo. The color and contrast of the image could also be affected. Just think for a minute about driving your car towards the sun. Even though your windshield may be clean, doesn't the sun shining on the windshield have an effect on what you see beyond it?

The one thing that you SHOULD do - all the time - is use a good lens hood on your lens. That will provide protection against stray light that could shine on the lens and cause problems. It will also provide mechanical protection, preventing fingerprints on the lens and warding off problems from bumps and bangs while carrying the camera.

Great info. Thanks Skip.

Nicely put, Skip.

What Skip said!

Any half decent modern lens has a multi coating which includes UV protection, and renders any UV filter redundant anyway. I don't use 'protection' filters on any of my lenses and haven't done so for many years. Putting a flat filter right on the front of your lens is really asking for flare problems. The exception is probably using a weather resistant lens and body in wet weather, when a filter is still recommended to stop water getting past the front lens element.

Polarizers indoors can cut reflections from shiny objects on the subject - glasses, buttons, jewelry, etc. They may also help with glare from oily skin. Basically, any reflections they'll work on outside they'll work on inside. If you encounter a situation where it might help, use it.

I have purchased a Circular Polarizing Filter, can you please tell me what is the advantage of the front element being able to revolve. I understand that you need that function with a linear filter, but I cannot see any advantage with a circular one.

"Linear" vs "Circular" does not mean that you need to rotate one and not the other. Both need to be rotated to achieve the level of the polarizing effect that you are looking for (i.e. cutting through reflections, etc.).

The significant difference is in how the light is seen by auto focus systems. Most autofocus systems can have problems functioning properly with linear polarizers.

How do you tell which you have? The easiest way to be absolutely sure that a polarizer is circular vs linear is to hold the filter up between you and a mirror. You want to be holding the filter so that, in the mirror, it covers the eye that you'd be using to look through the filter. Thus, you are looking through the filter twice to see your eye in the mirror. Then flip-flop the filter so you are looking at the other side of it. If you have a linear polarizer, you will be able to see your eye in the mirror with the filter held both ways. If it's a circular polarizer, you will see it blacked out in one direction and the other direction you'll be able to see your eye in the mirror.

Skip, Many thanks for that advice.
I had already done the circular vs linear test. that was positive.
The filter is a Hoya Cir-polarizing so I didn't anticipate that it would be different to what it said of the case.
So now I am eagerly waiting for a "blue sky day" to try out this filter.
However I do wonder if I should have purchased a Hoya HMC or a Hoya Super HMC or the new HOYA Digital Circular Polarizer ?