New Polarizing Filter On An A70

[Ah Pook]

Hello,

I have an A70 and recently picked up a lens adapter and Promaster/Hoya circular polarizing filter. Used the filter in about four different shooting situations. Mostly shooting landscapes with a sky horizon. The filter has slowed the shutter speed down and opened the aperture up more. The downside is that the foreground is being washed out. Yellow grass is turned to light brown. Bright pink is washed out. The pics are loosing their bright color. All this and the skies are not any more vivid. Any ideas to correct the color?

I know a Grad ND filter might also help with the sky but the washed out color is more of a concern.

Thanks.

[stopbath]

ah pook wrote:
Hello,

I have an A70 and recently picked up a lens adapter and Promaster/Hoya circular polarizing filter. Used the filter in about four different shooting situations. Mostly shooting landscapes with a sky horizon. The filter has slowed the shutter speed down and opened the aperture up more. The downside is that the foreground is being washed out. Yellow grass is turned to light brown. Bright pink is washed out. The pics are loosing their bright color. All this and the skies are not any more vivid. Any ideas to correct the color?

I know a Grad ND filter might also help with the sky but the washed out color is more of a concern.

Thanks.
Any samples? Normal shot without filter, same shot but with filter aligned (darkens the sky), same shot again but with filter not aligned. (Using fresh meter reading each time.)

The desciption given does not make sense. A scenery shot should not over expose the foreground by using a polarizer. It should cut down on reflections and actually make the colours more vibrant.

[jinushaun]

I agree with stopbath. Is your filter aligned? (check by aiming at glass wall/window and rotating the filter until you can see inside)

[sleeping_tiger_62]

For landscape photography where you have a very bright sky compared to the ground terrain, a graduated ND filter will be much more helpful than the polariser for balancing the brightness of the image.

The polariser reduces the intensity of the entire image, so the relative difference in intensity between the sky and ground is still the same. With the graduated filter, you should be able to get the original color of the ground terrain right as the lens will be looking at it through the clear part of the filter.

If you are using the polariser, you should try to use Aperture priority mode (Av) to automatically increase the exposure time while setting the aperture number to the highest on your camera (e.g. f8 on the A80). This will ensure that the photo stays sharp.

To effectively use the polariser to enhance the sky and clouds vividness, you need to use it with the sun at right angles to the lens. For example, when the sun is setting in the West, point your camera North or South. This way, you will get the best effect. Of course, that means you need to do some planning on the time of day or location you need to be (or check where you happen to be). Pointing the polariser into the sun or with it behind you will have little effect.

If you are really keen, invest a little into a mount that can hold multiple filters for some pretty cool effects. Of course, some people will use digital post processing with their PC software to create the effects instead.

[stopbath]

The polarizer cuts out two types of light: Polarized reflected and refracted light.

Reflected light is light reflected off non-metalic surfaces (like a window, or plant leaves.) This will help produce more saturated colours.

Refracted light is light dispersion such as from the sky. When looking at the sky, with the sun 90 degrees from your focal point, the sky will include a lot of polarized light from the sun. The filter can remove some of this, but on wide angle shots the deepened colour is not full frame. It's only partial. Use a telephoto lens to keep the deepened sky full frame. Looking at the sun and directly away from the sun, the polarizor is less usefull and acts more as a neutral denisity. It can still remove the reflected light though at this point.

As long as you use incamera metering after attaching and adjusting the filter, do not concern yourself with exposure compensation. Shoot your scene as you wish to include or exclude depth of field, or motion. It will be metered correctly. Only worry about compensation if using a hand held meter.

[Ah Pook]

Howdy all,

Sorry it's taken me so long to get back here.

Wow! Some good info here.

stopbath wrote:

Any samples? Normal shot without filter, same shot but with filter aligned (darkens the sky), same shot again but with filter not aligned. (Using fresh meter reading each time.)

A scenery shot should not over expose the foreground by using a polarizer.

Here are some examples. The pic details are in the title. http://www.picturetrail.com/ahpook1

This outhouse (in reality) is a bright pink.
http://pic8.picturetrail.com:80/VOL259/1616428/3257669/39958695.jpg%20

jinushaun wrote:
Is your filter aligned?

This is a new one on me. Never heard of aligning the filter. I'll give it a try.

sleeping_tiger_62 wrote:

To effectively use the polariser to enhance the sky and clouds vividness, you need to use it with the sun at right angles to the lens. Pointing the polariser into the sun or with it behind you will have little effect.

If you are really keen, invest a little into a mount that can hold multiple filters for some pretty cool effects.

I have recently learned of using the polarizing filter at right angles to the sun. In the sample pics, it looks like I was shooting at right angles (or close) to the sun. All my research on filters didn't mention that one. Funny how salesmen, on commission, leave this kind of stuff out. :) A filter mount may be in my future.

I haven't had time to shoot many more test images. If we would get some snow up here, I might get out and experiment some more.

Thanks for all the help. I'll keep ya posted.

[sleeping_tiger_62]

Just had a thought about your problem with getting the colors right. Perhaps it is something to do with the White Balancing setting on your camera?

Try different settings to see what they do to the colors, e.g. Auto (AWB), daylight, cloudy, or even set the white balance with the custom setting (mine is an A80, so I don't really know if you have this feature with your A70) with the polariser mounted and aiming the camera at a really white piece of paper. It might help.

Hope if you try it you will share with us what happens. Sometimes its a real wonder what results these electronic gizmos give.