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[OM] Re: Re Moose's F30 suggestion

Subject: [OM] Re: Re Moose's F30 suggestion
From: Moose <olymoose@xxxxxxxxx>
Date: Wed, 21 Jun 2006 13:13:27 -0700
Walt Wayman wrote:
> But to the point: Why not just make the correction in post processing.  The 
> effects of an 81A filter should be easy enough.  I've got bunches and bunches 
> of filters, but I don't use any, except polarizers, for digital since it's so 
> easy to mimic the effects in either PWP or PS.
>   
The 81 series are one of two types of filters whose effect cannot be 
fully duplicated in post. The other one is, of course, the polarizer and 
its ability to control reflections.

At any altitude reachable in Georgia, and indeed the East Coast, you are 
correct. At the altitudes Wayne shoots at in the Bolivian Andes, UV is 
very high level. The problem is that the blue sensors in the camera or 
film can't differentiate between UV and visible blue light. So when you 
correct the excessive blue in some parts of the subject, it throws off 
the color balance in the other parts.

Some shots can be corrected nicely in post. Others, even with masking of 
different areas of the image, can be very difficult to make natural 
looking. I tried that on a couple of Wayne's images when he first posted 
some from Bolivia with problems a few years ago. After all those 
discussions, he started using 81 series filters, which nicely fixed the 
problem.

Interestingly, if one is always going to post process ones images, it's 
better to use too strong an 81 filter than not strong enough. Over 
filtering makes sure there is no UV effect and the other color balance 
problem is easy to correct.

I've just looked at the lens on the F30. What I would do is buy some 81 
a or b gel filter(s), cut out appropriate sized circles and carry a 
little baggie of them and a roll of double stick tape. The gels are 
cheap and each piece should be usable several times. There is a big 
enough circle of metal surrounding the actual lens opening to do this in 
a way that won't interfere with the lens opening and closing.

If one happens to be left on for an indoor or other shot, flash or not, 
where it over warms it can easily be corrected in an editor.

Moose

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