Converting JVC digital camcorder to IR sensitive camcorder

[Rolland Elliott <liquidriver@xxxxxxxxx>]

I had time during the holidays to disassemble my JVC
GRDV1 digital camcorder. It's been eating up tapes
towards the end ocassionally, so I didn't feel that
bad if I were to break it while experimenting on it.

This camcorder is very small (about the size of a
small paperback novel) and is sensitive to IR light,
but only to a very slight degree.  One has to set the
camcorder to it's highest gain up level and also set
the shutter speed to 1/4 of a second, which gives
moving objects a very blurry look (kind of neat, but
it gets old quick). In addition the camcorder needs
bright sunlight to record IR light.

After fiddling with the camcorder for a long time, I
managed to get to the heart of the machine, the CCD
(it's the sensor which actually records the light, I
think it stands for Charged Coupled Device), After
removing the CCD from the lens assembly, I found
exactly what I wanted: a small blue green IR blocking
filter. This filter is quite a bit darker than the IR
blocking filter made by B&W filter company in Germany.

Anyways, I removed the IR blocking filter and
reassembled the camcorder.  Unfortunately, I couldn't
get the camcorder to focus.  I immediately remembered
that a focus correction is needed for IR light. So I
again disassembled the camcorder and added a small
paper spacer between the lens assembly and the CCD; I
thought IR light focuses farther away than visible
light so I thought I would need to move the CCD farter
back from the lens.  After putting the camcorder back
together a second time, it still wouldn't focus
properly.

So I opened it up a 3rd time and took out the paper
spacer (about 0.5mm thick) and I also REMOVED an
aluminum spacer in the camcorder to make the CCD about
1 mm closer to the lens.
Then I put the camcorder back together for a third
time ( I was getting pretty good at taking it apart by
now).  
Focusing worked great! Finally! It still seems to me
that the CCD should have been moved farther away,
perhaps someone can explain IR focuing correction to
me so I understand it better.

By removing the IR blocking filter the camcorder works
great now for IR movie making.  I set it to sepia or
black and white mode with an 87 filter over the lens
and I can easily record under normal light levels (for
example inside using a 60W tungsten light bulb)

I realize that Sony makes NIGHT SHOT camcorders with
IR sensitivity, but I always thought the green tint
made these IR pictures rather ugly.  It is really neat
to preview an IR scene in Sepia tone using my
camcorder.  I spent a couple of days just looking
around stuff in my house; here are some
surprising/interesting observations:

1. IR remote controls make a very unusual circular
concentric light pattern.
2. The black felt on some of my Nikon lens hoods is a
very good REFLECTOR of IR light, so it shows up white,
which is about the worse thing for a lens hood to do.
3. A Mamiya zoom lens I have has what looks like a
black anodized finish on it.  Under IR light the black
finish is another good reflector of IR light and my IR
sensitive camcorder makes it look like a nice shiny
silver lens. Even more depressing is the inside of the
lens is also shinny, so IR light can easily bounce
around and cause flare. 
4.  The film plate back in my Nikon N90s camera has a
similar black anodized finish, and when I look through
my camcorder the previously black plate now looks like
a piece of aluminum foil.  So that's why putting a
piece of aluminum foil over the film back had no
effect on exposure or halation. The pressure plate was
already a good reflector of IR light!
5. Many ariticles of dark clothing appear light.
6. I look like a real dork in my sunglasses, since IR
light makes them look like dorky horned rimmed glasses
with clear lenses.
7.  Computer monitors are vertually unreadable.
8.  Photographic prints are very faded when viewing
through a 87 filter. Through an 87A filter all prints
look like a light grey piece of paper.
9.The IR blocking filter that B&W in Germany makes
isn't really that good at blocking IR light.

The neat thing about this experiment, is that these
digital camcorders can be had on ebay for around $500
dollars.  The sony digital camcorders with night shot
mode all cost over $1000.  So one can save a lot of
money.

The down side is that one has to dedicate the
camcorder to IR film making since the IR blocking
filter is not easily removed and reattached and the
postion of the CCD has to be altered.

Take care

__________________________________________________
Do You Yahoo!?
Talk to your friends online with Yahoo! Messenger.
http://messenger.yahoo.com
*
****
*******
******************************************************
*  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  *
******************************************************