Re: Tiny cameras for infrared

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

On 18 Jun 97 at 17:10, Joe Berenbaum wrote:

> I'm thinking of putting a dark red filter inside a pocketable compact camera
> for use with Kodak High Speed Infrared. When I say pocketable I mean really
> tiny. I already use a Rollei 35 for this with a filter on the lens but it is
> still quite a lump and won't go in a trouser pocket comfortably. I mostly
> use this combination for Infrared Ektachrome since that's the infrared film
> I use mostly- but that may change. I'm looking at the very small compacts
> such as the Olympus XA, XA4, and the Minox 35ML, but all of these have
> visibly dimpled pressure plates. But then so does the Rollei 35, and I
> haven't had a problem with that yet. Maybe I need to look again at those
> pictures! So two questions; 

Before you make too many people happy: for HIE you almost certainly need a 
manual camera, or one that allows easy ASA adjustment. I assume EIR 
doesn't have an ASA label on the cartridge either.
(reminds me of the picture of a HIE cartridge in ColorFoto 
7/97....never seen one before, I have never developed it myself, I 
only handled it in the dark....:-))

> 1] Has anyone used the Rollei 35/35S for High-Speed Infrared? And if so,
> does the lightly dimpled pressure plate ever cause a problem with this film?
> 2] Can anyone state what degree of dimpling (on a pressure plate) causes
> problems with High-Speed Infrared- or does any degree of dimpling at all
> cause a problem?

I believe in my previous Minolta 7000/9000 there was a slightly dimpled pressure 
plate, and in my current EOS-1 the plate is attached with two 
pop-nuts, the top one inside the image area (otherwise smooth).

> And one other questionm, while I'm here-
> 3] Do behind the lens filters (ie in front of the film plane- just) cause
> any focus shift or focus error, and if so, is this more likely or less
> likely with wideangle lenses?

The focus shift is caused by the lens and depends on what filter you
use (ie which part of the spectrum, or the relative amount of
IR....less shift needed with #25 than with #87B), not by the
location of the filter.
I haven't changed my focus correction since I use a #87C between the 
film rails. But rest assured I still screw up a nice 200mm shot once in a 
while when I forget to correct focus....8-(( 
(anyone an Angenieux 180/2.3 APO in either Leica-R or Nikon mount for 
sale? I want to get rid of this dreadful focus shift!....8-))



- -- 
Bye,

Willem-Jan Markerink


      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-Digest V0 #68
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