RE: Focus Correction on Sigma APO's and EIR film

["ROLLAND ELLIOTT (Quality Assurance Co-Op)" <rolland.elliott@xxxxxxxxxxxxxxx>]

<I just spoke to a Sigma rep, who claimed that their APO's didn't need
< focus correction for IR either I hesitate to believe that right away.the guy
said the deviation
 <was too little to put it on the DOF scale.so the question is: has
 <any of you ever run (focus) tests on HIE with a Sigma APO at full
 <aperture?

I have a Sigma 70-210 f/2.8 APO zoom lens for my Nikon N90s.  I have never
tried focus tests with HIE, but I did do a couple of focus tests with EIR.  I
used a Kodak 87C BTFR filter and focused on a piece of paper with some writting
on it about 2 meters away.  On a tripod the N90s camera was set to matrix
metering. Lens set to 210mm & f/2.8 and film speed was rated at EI=50.  At
 these settings the depth of field should approximately be 1.5 cm.  The slides
showed the subject in focus, but rather dark.  I was surprised since I expected
to get an out of focus image.  I reread the instruction sheet that came with my
Sigma zoom and it states that the infrared correction mark on the zoom lens is
for the 70mm end of the zoom only.  No IR focus correction needs to be done
when using the 210mm end.

As far as shooting EIR with an 87C filter goes, I did it just to see what would
happen.  The results were rather dull.  As expected, the only colors my slide
film recorded were red and black.  Not that interesting.  IR effects were hard
to discern.  I didnt notice any glowing foilage or highlights.  The few slides
I shot were underexposed though.  If anyone wants to try this Id recommend an
EI=25, shooting in full sunlight around noon, and bracketing +-0.5 EV around
your metered exposure.  I took 1 or 2 pictures when the sun was behind the
clouds and the resulting slides were really underexposed.

Here are some other observations Ive made after shooting about 6 rolls of EIR.
Almost all of my pictures were taken with a yellow #12 filter (also known as a
minus blue filter since it filters out all blue light) & a circular polarizer.
I also used a red #25 filter and polarizer on some shots.  I prefer the yellow
filter much much better.  The red filter gives yellow clouds and orange/red
vegetation, but the range of colors it records is very small since it blocks
out most green and blue light.  The few pictures Ive taken with a red filter
look like they suffer from color balance problems because there is so much red
and orange colors in the pictures and very few other colors.

The use of a polarizer filter isnt absolutely necessary, but it will increase
your color saturation.
The best thing I like about this film is that it cuts through haze and makes
landscape photographs much clearer.  I took pictures at an airplane show with
this film and the clouds were really white while the sky was a very nice dark
blue.  Ive also taken some nature shots with this film and some nudes.  Here
are my observations when using this film with a yellow #12 and polarizer
filter:

An ISO setting of 200 works well, if you want increased saturation set your
camera to -0.3EV or ISO=250, this is what I prefer.
Green vegetation will record red or bright magenta in full sunlight.  In shade,






the color of vegetation will be the same, but the color saturation will be a
lot less.
Various colors of oil paints will show up as yellow on this film.  I took a
picture of a green volkswagon bug and it turned out yellow.  I also took some
pictures of some red airplanes and the red paint was yellow on the slides.
Pictures of white oil paint seems to remain white.
For people/nude shots.  Skin tones reproduce fairly close to what you see, with
a few exceptions.  Lips will be yellowish/orange instead of pink.  Eyes
ususally remain the same color, but I have noticed that sometimes eyes will
have a red/magenta tint if sunlight is directly hitting them.  Tan lines seem
to be much more evident when shooting with this film.  Direct strong sunlight
washes out detail and imperfections in the skin.  Indirect, soft lighting
from the sun wont wash out details in skin.

Ive shot many different flowers with this film.  Almost all flowers show up
yellow while the vegetation surrounding them is magenta.  The resulting slides
usually only have two main colors in them, magenta and yellow, which looks dull
to me.  I think I perfer shooting flowers with regular slide film which gives a
much wider range of colors.

As Kodak mentions in its data sheet, exposures longer than 1/10 of a second
will require +1.0EV of exposure compensation, this is due to recipricocity
failure of the film. I wasted a couple of shots before I remembered this.  I
take a lot of my pictures with a tripod so I often use long shutter speeds and
smaller aperatures.  I havent shot enough film yet, but I think long exposures
might also effect the color balance of the film.

In addition to red specks on a few frames Ive noticed blue streaks  on some
slides.   Is anyone else having trouble with blue streaks with their EIR film?
I developed all my EIR using Kodak E-6 chemicals.

Have fun!  Rolland

Work Phone is 614-772-3537 Home # 614-772-2854
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End of Infrared-Digest V0 #159
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