Archived posting to the Leica Users Group, 2005/02/07
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 2:02 AM -0800 2/7/05, Mark Rabiner wrote:
> >>
>>
>> It's 'cost free' if you shoot RAW, or rather, it doesn't matter what
>> the camera is set at. When you convert it, import it, whatever, the
>> software will show the file as it was 'tagged' by the camera
>> software, but the info is the same no matter what parameters you set.
>> Note that using filters with a digital camera doesn't really gain you
>> as much as you might think, as you filter out some information that
>> you don't want, and therefore relatively boost some other info.
>> Photoshop, or rather Camera Raw, does similar things but you are not
>> penalized as much w.r.t. shooting sensitivity.
>>
>
>
>Henning, If you were at a very high, like near top of mountain, say Mt. Hood
>altitude where the sky is blue purple and the color temperature is way say
>81c or D to correct I thought that cutting out that blue before it hits the
>film could prevent a color cross over that you'd get by trying to correct it
>later?!?
>
>Not that color cross overs can not be dealt with in Photoshop.
>
>But not by weekend Photoshop users! :)
There's something to that, but you have to remember that most filters
also introduce anomalies that lead to colour cross-over. Different
companies have generally produced filters with different spectral
responses, even though their 2D graphs might show the same curve on
the standard Y-B axis.
The other matter is that at high altitudes high UV levels can cause
problems with the spectral response of digital (or film) cameras, and
the UV absorption that is built into lenses now might not be enough.
It might be necessary to use a 'hot' UV filter to provide a sharp
enough cutoff.
Still, the controls available in PS allow a much greater control of
colours than was ever possible with analog means, as you can control
each channel, and to some extent, even control the exact axis of that
channel.
In the end, I would leave off the filter, except maybe the super
sharp cutoff UV filter (which costs you one or two of the limbs you
need to get to that height).
--
* Henning J. Wulff
/|\ Wulff Photography & Design
/###\ mailto:henningw@archiphoto.com
|[ ]| http://www.archiphoto.com