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sponner
23rd June 2011, 06:24 PM
May I pick your collective brains.

I have taken quite a few shots where the subject is in focus and seems ok exposure wise but the sky is blown out and virtually white, usually on bright days bit with a fair mount of cloud and aslo on clear days at times.

Is a graduated ND filter what I need? If so what is it!

Does it automatically darken teh brighter areas while leaving the darker areas correctly exposed?

Is there a down side to their use?

jamie allan
23rd June 2011, 06:33 PM
For days where there is a fair bit of blue in the sky a Circular Polarising Filter might help.

The Saint
23rd June 2011, 06:46 PM
Sponner

A graduated nd filter would definitely help, however it is not automatic. The simplest way to think of a nd filter is half of it is clear and the other half is tinted. You fixed the filter to the front of your lens, typically in a mount then move the filter up or down until the bright area, in this case the sky, is obscured by the tinted section, which therefore reduces the light getting to the cameras sensor and minimising the blow highlights (the White sky). The dull that area and the foreground is in the clear section of the filter and therefore stays at the original brightness as no light is cut out from reaching the cameras sensor.

There are fairly easy to use, however it works best if you have the camera attached to a tripod.

Another method of achieve a similar result is by using HDR (several images of the same scene at different exposures and then merging them together post production on the computer which takes the correctly exposure portions and merges them together).

This a relatively non-technical explanation and I'm sure others could explain all the science behind it.

Simon

sponner
23rd June 2011, 07:02 PM
Thanks Simon, I was barking up the wrong tree, your explanation is crystal clear

creigb
1st July 2011, 08:04 AM
This seems quite informative http://www.singh-ray.com/index.html

sponner
1st July 2011, 09:26 AM
thanks for that