Re: Focus (Stupid Question?)

[Clive Warren <Clive.Warren@xxxxxxxxxxxxxx>]

At 6:19 pm -0400 17/6/00, Raymond & Christine Worrilow wrote:

>I have the Canon a2e and I'm interested in trying some of the Konica IR
>film.. But none of my lenses seem to have the IR (red focus line) can
>anyone tell me (in laymens terms) how I could go about focusing for a sharp
>picture?
>
>My lenses are
>
>Tamron 90mm (macro)
>Tamron 28-200
>Tamron 200-400
>
>Also I no the Konica wont give me the white foilage like the kodak IR film
>will.. but what filter can I use that will bring me the closest to this
>effect?
>
>					Thanks...!!
>						Ray Worrilow

Hello Ray,

Without an infrared focussing mark and using an R72 (Wratten spec. #89B)
filter, nudge the focus a small amount closer, use f11 and you will have
focussed photographs with white foliage.  Check out the dog on the CoCam
website front page and all of my infrared gallery shots.  These were all
shot with Konica IR750 and an R72 filter - usually at f11 - and clearly
show the "white foliage" effect.

However, the burned out highlight effect obtainable using Kodak HIE is due
to there being no ant-halation backing to the film and infrared light being
reflected from the film pressure plate back into the film.  You will not
get this effect from Konica film.


As the focal length increases, the focussing adjustment will become more
critical for closer objects. It would probably be a good idea to approach
Tamron and ask them about infrared focussing in terms of degrees of
focussing ring movement - they may be able to help you.

There is loads more information in the Infrared FAQ on the above subjects,
including an exposure chart for various infrared films with various filters
- URL in sig. file.

Generally I would recommend the R72 filter with Konica IR 750 film. I have
used an 88A also but this increases contrast further on a film which is
already high contrast making it a bit of a challenge to print.






All the best,

             Clive   http://www.cocam.co.uk
                     Photographic Services, Filters and Equipment, Infrared FAQ


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