Re: Exposure for 87C

[ANDPPH@xxxxxxxxxxxxxxxxxx]

>>I guess I must have missed a few postings at some point so would you mind
>>telling me how you mounted an 87c filter behind the shutter.  What sort of
>>material did you use?  My primary 35mm for HIE is an Olympus Wide E.
>> However, the 35mm camera I use for everything else is a Contax 167MT. 
>
>  I cannot remmember who the originator was, but I believe the suggestion
>was on the list several weeks ago.  It was to cut a Kodak Wratten 87c
>gelatin filter to fit behind the shutter on the inside back of the camera
>body. <snip>

There was an article in the PSA Journal many years ago (mid 70's?) where this
procedure along with calibrating a Luna Pro for use as a quite relaible IR
meter was described. I wrote that article after having presented the subject 
at many photographic conferences previously. The "procedure" was simply a
derivative  of other situations where placing some material between the film
rails was an effective way to solve a problem.                 

If you could live with dedicating a camera on a fairly regular basis for IR
work I'd suggest placing it inside the throat of the camera in such a location
that the filter material would be removed from the film surface by a few
millimeters. This minimizes the chance of small dust particles casting a shadow
on the film. It also prevents small IR leaks around the top and bottom edges 
of the filter when it is installed between the film plane rails. 

The article is at:  http://www.isc.rit.edu/~andpph/text-infrared-action.html

Anytime one is "messing" with installing anything inside the throat of the
camera one should do it by first fully understanding what goes on in there ...
some cameras have mirrors behind the main mirror, etc. In fact, this advice
should apply to _any_ modification one attempts on any camera!

BTW, I don't claim that was the _first_ time somebody mentioned this placement
for the IR filter but to the best of my knowledge there was no earlier
reference to it.  ;-)

Andy

 o o  0 0 o   o  Andrew Davidhazy, Imaging and Photo Tech - High Speed Photo
  \/\/\/\/\/\/   andpph@xxxxxxx,  http://www.rit.edu/~andpph,   716-475-2592  
___|        |_______________________________________________________________
                 PhotoTech Department:   http://www.rit.edu/~andpph/ipt.html
*
****
*******
******************************************************
*  To remove yourself from this list, send:          *
*         UNSUBSCRIBE INFRARED                       *
*       to                                           *
*         MAJORDOMO@xxxxx                            *
*----------------------------------------------------*
*   For the IR-FAQ, IR-Gallery and heaps of links:   *
*  http://www.a1.nl/phomepag/markerink/mainpage.htm  *
******************************************************

------------------------------