BetterPhoto Q&A
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Effect Of Polarizer on Foreground subject

I had used ISO-400 film and most of the occasions either used 'Av' that is aperture priority with high f number. For better depth of filed or 'Tv' or used the programmed (P) mode or Auto mode. I had never used manual focus.

What went wrong? Was I not supposed to use the polarizer with someone in the foreground? Is the polarizer meant for landscape snaps only.

Will very much appreciate your help.

Thanks... Ujjwal

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March 22, 2001

First, a little more information about polarizers. A polarizer will only reduce polarized glare. Only non-conductive surfaces such as water, glass and sky produce polarized glare. Metal will not and a polarizer will not affect glare from it! Also, the angle of the glare reflection will determine how effective your polarizer will be. For making darker blue sky, the sun needs to be more to your right or left and not directly behind you or directly in front of you.

It should reduce some of the glare from the specular highlights off of the water, and should also make the sky darker blue (with the caveats above about sun position).

Light sandy beach and snow scenes can be very bright if there is a lot of sand or snow . . . about a stop brighter than the sunny-16 rule. This is because light sand, water and snow is very reflective.

If you can upload a scan of an example image it would be easier to diagnose what happened. I'm only guessing at this, but from your description you have have had very bright surroundings that were about a stop brighter (on average) than your subjects . . . even if they were in direct sunlight. This can create a situation where the brighter surroundings detract from your intended subject material, as if they were lightly shadowed and more subdued. The visual effect is attention drawn more to the brighter areas of the scene and less to the subject(s). This effect increases as you make the subjects smaller to include more of the very bright surroundings.

Take a look at your prints and see if this is what happened. A polarizer might help some with bright water reflections if the sunlight angle allows removing some of the glare . . . but it won't help with the brightness of the sand.

Continue taking your polarizer with you. It's a very useful tool in certain situations; there is _always_ one in my camera bag. When you're not making photographs, experiment with it on the lens to learn more about how it works and under what conditions.

-- John

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March 22, 2001

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March 23, 2001

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March 23, 2001

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March 23, 2001

It's funny you should ask this question just at this time, I just asked my manager, who used to be professional photographer, a very similar question.

My question was - why wasn't my circ. pol. working? I was metering off someone's skin and adding one stop, so thought I had perfect exposure... But the sky was all washed out, even with a circular polariser.

What happened was, since it was a very bright day, if the person was correctly exposed, then the sky was way over exposed - hence the whited out look. If I had exposed for the sky, then the person would have been too dark. I think the problem here was exposure latitude - the difference in brightness between the person and the sky was too much for the film to capture.

I'm only extrapolating, so take my advice with a grain of salt, especially since I haven't seen your photos, but hey, since the experience was so recent to me, I thought I'd add this in :)

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March 23, 2001

1. Next time you are out on a sunny day with a clear sky, either in the morning or the evening, put the polarizer on and look to the north or south. Rotate the polarizer for the deepest blue sky. Then turn slowly away from the sun. You will see the polarizer effect decrease; the sky will start to get lighter. It should be lightest when you are looking in the direction opposit the sun. This _won't_ work nearly as well at mid-day between about 10AM - 2PM; it's best to do it before or after that time.

2. Next time you're in an urban setting with store windows, put the polarizer on again. Turn yourself to about 45 degrees to the glass window. Rotate the polarizer until the reflection on the glass window disappears. Then slowly turn or reposition yourself until you are looking straight at the window. You should see the effect of the polarizer eliminating reflection decrease to nearly none at all when you are looking at your own reflection. About 45 degrees to the window glass is optimal for eliminating reflective glare from most glass.

3. You can perform the same experiment near a lake or other large body of water that shows a lot of sunlight reflection on the surface.

The best angle for a polarizer is based on the index of refraction for the surface from which you are eliminating the reflective glare, so it is different between glass, water and the Earth's atmosphere (the sky) because they all have different indices of refraction.

-- John

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March 23, 2001

Now my question to you is what exposure do you recommend in similar situation where difference in brightness between the foreground subject and the sky is very high without the use of a polarizer. Will it be a good idea to use exposure bracketing? and whether that recommended exposure will be different if you are using a polarizer.

Thanks Ken for sharing you experience. It helped me in coming out with these questions... ujjwal

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March 24, 2001

Ken: the pictures are here now...

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March 25, 2001

Hoping Ken and Jeff will weigh in on this with what they think too.

Looks more like light direction and the shadowing it created than anything having to do with your polarizer. Looked for shadows of other objects in them to reveal exactly where the sun was in relationship to you and the subjects, but didn't see anything conclusive.

From looking at the subjects it appears as if the sun is mostly to their side and slightly behind them. If you turn them too much into facing the sun, their eyes will squint. In situations like this, consider using fill flash if the subject is close enough to use your flash. It will illuminate the subject, but not affect exposure of a distant background. It's suitable for environmental portraiture similar to what you were doing in these. In using fill, set exposure for the background and bring the shadowed subject up to its brightness level with it. The camera's shutter speed also needs to be set to one at which it can X-sync the flash properly.

The alternative is to shade the subject completely, expose for that, and let the background wash out some. It requires being closer to the subjects to fill the frame with them, and giving up background details. It's more suitable for portraiture in which the background location isn't an important element. I've done this in the past with an assistant just outside the frame holding something like a jacket or coat to shade the subject. If there's a lot of background the printer may try to expose the print for both subject and background ending up with a darker subject than intended. (A good printer will not do this.)

Our eyes, and how our brains process what they send it, have much more latitude than any film. Things like this won't jump out at you when you are looking through the viewfinder. You have to deliberately look for it. What to look for and what to do to compensate comes with analyzing results, trying different techniques, and experience with them.

-- John

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March 26, 2001

ujjwal

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March 26, 2001