On Fri, 26 Sep 2008 17:11:35 +1200, Eric Stevens wrote:
On Thu, 25 Sep 2008 07:44:25 -0700, DaveC wrote:
I want to photograph and video in infrared mode.
I understand that some point-and-shoot cameras provide this style of
photography/videography. Alternately, some people have "hacked" a camera by
removing the IR filter from in front of the imaging element. There are
instructions on-line to DIY this, or to send in your P&S to have it done.
Basically, the IR filter is removed and replaced with another (not a
procedure for the faint at heart). The replacement filter is $$$.
My question is this: is this replacement filter that passes rather than
blocks IR available as a gelatin or other commonly available filter that I
can source elsewhere other than from these camera-mod services?
Or can I just strip off the existing filter and not replace it with anything?
I'm looking for quantitative data (the existence of IR) not qualitative data
(a pretty picture). What function does the replacement filter provide (other
than passing IR data)?
To clarify, I want to "see" IR images real-time in the viewfinder, not
post-process the image data to reveal the IR.
If there's another forum you suggest I should ask this question in, please
let me know.
You could try picking up a Sony F707 or others of that ilk. If my
memory serves me right they do have IR capabilities.
Correct, the Sony F707, F717, F818, H3(?), and H9 all have this capability, and
they all do it very well. Real-time hand-held IR photography and videos are a
feature of all of them. No need to hack or alter any camera, just flip a switch
to their "Night-Shot" mode.
According to my add-on lenses and things, I would have to go with a 62mm filter
size to make it the most adaptable to the most situations (including for use
with my 35mm film gear). When looking at IR filters I was shocked at the prices
so I went in search of an affordable alternative.
The Kodak Wratten Gel Filters come in 3"x3" sizes. I could cut one of those up
into a circle and put it inside of an inexpensive filter-ring holder. But
they're prone to water-damage, humidity, etc. And they're still about $25-$30
depending where you get them, that's probably not worth the hassle and care for
the few dollars savings.
Then I found some 3"x3", Lee Polyester IR filters at B&H for only $14. Durable,
worth the cost for an experiment. I didn't want near-infrared, I wanted infrared
only, so I opted to go with the Wratten #87. $14 for the filter, and $10-$15 for
a cheap skylight filter (to dismantle for the mount, I couldn't find a source of
empty filter-ring holders), and I'd be good to go for under $30. If you have an
old filter that you can dismantle for the filter-ring, more power to you, then
you can get into IR photography for only $14.
Here's those Lee filters at B&H Photo & Video if anyone else wants to go this
route:
http://www.bhphotovideo.com/bh4.sph/...=F 5261AD1470
Normally a decent IR filter of the size needed can run you upwards of $70-$130,
you can see the kind of savings attained by doing it this way.
A problem with all these Sony cameras is that Sony stupidly listened to some
sexually-insecure puritanical idiots at one point and crippled the shutter
speeds and apertures that may be used in their Night-Shot mode. They were
concerned that some people were using them to shoot through certain swim-wear
fabrics at the beach, fabrics transparent to IR. For daylight IR photography you
have to lower the IR levels to those required for shooting in the dark. I
experimented and found out that a Wratten Green filter (for b/w photography)
lowered the levels just right. I found an inexpensive Hoya G (XI). In total you
are using a two filter stack, IR + Wratten Green.
One other thing, you have to make a rubber gasket to cover up Sony's own IR
emitters in the lens housing, that the camera uses to take photos in complete
darkness. Otherwise the IR from those bounces off the back of the filter stack
and into your lens, ruining your shots with nasty light reflection artifacts in
the glass layers.
Here's a quick sample of a hand-held daylight IR shot from one of these cameras
http://farm4.static.flickr.com/3085/...e6058929_o.jpg