Motion/filters (was: Bio

["Willem-Jan Markerink" <w.j.markerink@xxxxx>]

On 12 Jan 97 at 15:24, Robert Long wrote:

> On Sat, 11 Jan 1997 15:54:39 GMT, Bob Peak wrote:
> 
> |filters I need.  I haven't found any but I would like to see if anyone =
> is
> |using IR for action shots (ie; smeared backgrounds, sharp focus on a =
> person
> 
> Interesting idea, but possibly self-defeating unless done very, very
> carefully.  Using mainstream films, the blurred elements in such
> action shots still suggest the real-world elements that produced them.
> They therefore suggest context and motion. With HIE and IRE, the
> blurred elements suffer two sea-changes: one due to the motion and one
> due to the film.  So unless you're very careful, these elements would
> be unreadable so to speak--like a text in regional patois, if you're
> an anglophone with only a standard Larousse.  However it might be
> quite exciting if superbly done.

The problem is finding a good IR-reflecting moving subject, and 
making sure that subject is sharp. Otherwise the highlights might 
fade with the not-so-sharp contours of the subject, loosing most of 
the impact HIE *could* have.
As for moving IR-reflecting subjects....a flying tree? Snow 
ball?....8-))
 
> Don't worry too much about filtration in the beginning.  Willem may
> wince at this, but it seems to me that there's far less difference
> between HIE exposed through a Wratten 25 and HIE exposed through one
> of Willem's "opaque" filters than there is between HIE with the
> Wratten 25 and, say Plus-X with a Wratten 25.  So get the feel of IR
> photography first with whatever filter comes to hand (usually a
> Wratten 25 or any other "dark red" model).  Once you do, you can
> decide whether the ultra-IR effect is worth going after for your
> particular purposes.  I knocked myself out tracking down a Wratten 29,
> which shaves off a little more of the visible-red bandwidth, and I'm
> not at all sure I can see the slightest difference between exposures
> made with it and ones made with the Wratten 25.

I would be surprised if you *could* see the difference. We are
talking about 20nm difference here....8-)) The difference between #25
and #87C is 100-250nm (depending on whether you take the 0% or 50%
transmission mark; the normal filters have a sharper cut-off than
the opaque ones). 

Keep in mind that darker filters do not increase the absolute amount
of IR, only the relative, by blocking out more and more of the
visible spectrum. They don't let you see more IR, only less visible, 
but it does have a strong impact on color/luminance perception.
I strongly feel that the unworldliness increases noticeably, even
with Konica from the examples I have seen.
Heck, I can even see the difference with my naked eye while looking 
through the borderline color #88 (barely visible, only by shading 
your eye), or when putting different filters on a night vision unit.

Willem (stepping off his soapbox now) Jan

--
Bye,

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      The desire to understand 
is sometimes far less intelligent than
     the inability to understand


<w.j.markerink@xxxxx>
[note: 'a-one' & 'en-el'!]

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End of INFRARED-PHOTOGRAPHY Digest 176
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