focus

[Llamapix@xxxxxxx]

Hi all.  A question regarding focusing which is not addressed in anything 
I've read about IR so far.  I am shooting Kodak HIE with a 25 red filter.    
I use a Canon AT-1 with Canon 28mm and 50mm lenses.

I have been shooting portraits with IR.  At first I shot some semi low-light 
pictures using larger apertures like f/3.5  In spite of careful focusing and 
offsetting to the IR mark, it seemed the subjects' faces were slightly out of 
focus.  I then theorized that perhaps since the film was being exposed by 
both visible and infrared light, that by using the offset focus I was 
therefore leaving all the visible light rays out of focus.  Is this the case?

Since then, I have been shooting with smaller apertures like f/8. and then 
setting the focus in between the normal and IR focus marks.  The greater 
depth of field easily encompasses both focus marks.  Yet in some of the 
pictures people's faces still seem a little soft.  Is this just the nature of 
IR?  Is it because of the high IR reflectance from people's skin combined 
with halation perhaps that makes them appear soft?  What are other people's 
experience with IR and portraits?

By the way, the softness has not really taken away the appeal from any of the 
pictures I have taken so far.  It has however got me scratching my head.

Thanks,
Gregg
*
****
*******
******************************************************
*  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  *
******************************************************