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DaveC September 25th 08 03:44 PM

Infrared photography
 
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.

Thanks,
--
DaveC

This is an invalid return address
Please reply in the news group


Eric Miller September 25th 08 04:15 PM

Infrared photography
 
"DaveC" wrote in message
obal.net...
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.

Thanks,
--
DaveC

This is an invalid return address
Please reply in the news group



I don't know much about most of this, but it seems that once you remove the
IR filter from the sensor, you could just attach an appropriate IR filter to
the front of the lens. Of course, you would need the appropriate filter for
each of the lenses that you use.

Eric Miller
www.dyesscreek.com



Jürgen Exner September 25th 08 04:25 PM

Infrared photography
 
DaveC wrote:
I'm looking for quantitative data (the existence of IR) not qualitative data
(a pretty picture).


Isn't that the other way round?
Qualitative meaning just yes/no while quantitative in addition tells you
how much, e.g. darker or lighter on a b/w IR-image or
blue/green/yellow/red/white on a color IR-image?

jue

DaveC September 25th 08 04:58 PM

Infrared photography
 
Isn't that the other way round?
Qualitative meaning just yes/no while quantitative in addition tells you
how much, e.g. darker or lighter on a b/w IR-image or
blue/green/yellow/red/white on a color IR-image?

jue


Quantitative: does it exist? do we have presence or absence? 0 or 0?

Qualitative: what are its qualities?

But to define in other terms, I want images that show the existence of IR
wavelengths. If it's not a pretty picture, that's OK.

Please let's not detour into this realm. Those who want to discuss
quantitative vs. qualitative please start another thread...

Thanks,
--
DaveC

This is an invalid return address
Please reply in the news group


bino September 25th 08 05:44 PM

Infrared photography
 
"DaveC" wrote in message
obal.net...
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.

Thanks,


The problem is that you won't see an IR picture per se, as the image
requires post processing to be anything but a dark red image. If your
camera has a B&W mode, that would be helpful, but the image will still
require post processing.


Whiskers September 25th 08 05:47 PM

Infrared photography
 
On 2008-09-25, 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.

Thanks,


Most digital cameras have some infra-red sensitivity left in - the
internal infra-red filters are there to stop most infra-red from getting
to the sensors, as it blurs the image (apart from anything else). The
infra-red filters sold to go in front of the camera lens do the opposite -
the stop most or all of the visible light but not the infra-red, so that
you can take pictures using only the IR. but because the intermal filter
blocks most of the IR, you need a long exposure (or an uncomfortable
amount of IR) to get any image at all.

It is possible to remove the internal IR-blocking filter from some digital
cameras (but probaly not compacts - the lens/sensor assembly in those is
ususally a non-servicable sealed module); usually you would then need to
replace it with an element having the same optical qualities in the
visible spectrum as the original IR-blocking filter had, or the resulting
images won't be usable. With such a camera, to get images using only the
IR spectrum, you'll need a filter in front of the lens to block the
visible light. All IR images from such a camera are likely to be more or
less blurred.

There are of course purpose-built thermal-imaging cameras, and IR 'remote
thermometers'. Some 'night vision' devices operate using 'passive IR'.
Oddly, these seem to tend towards the 'stupidly expensive' end of the
price spectrum, being targeted at the armed forces and emergency services,
or for industrial or medical uses.

This site might be useful
http://www.wrotniak.net/photo/infrared/#CAMERA.

--
-- ^^^^^^^^^^
-- Whiskers
-- ~~~~~~~~~~

Jürgen Exner September 25th 08 06:23 PM

OT: qualitative/quantitative (WAS: Infrared photography)
 
DaveC wrote:
Isn't that the other way round?
Qualitative meaning just yes/no while quantitative in addition tells you
how much, e.g. darker or lighter on a b/w IR-image or
blue/green/yellow/red/white on a color IR-image?


Quantitative: does it exist? do we have presence or absence? 0 or 0?
Qualitative: what are its qualities?


That is opposite to what I learned in science, especially in chemistry.

There a qualitative analysis tells you _which_ components are present in
a sample (yes/no).
And a quantitative analysis tells you _how much_ (what quantity) of each
component can be found.

Wikipedia seems to support this view:
"A quantitative attribute is one that exists in a range of magnitudes,
and can therefore be measured. Measurements of any particular
quantitative property are expressed as a specific quantity, referred to
as a unit, multiplied by a number. Examples of physical quantities are
distance, mass, and time."

Please let's not detour into this realm. Those who want to discuss
quantitative vs. qualitative please start another thread...


Ooops :-). "Subject" adjusted as requested.

jue

nospam September 25th 08 09:31 PM

Infrared photography
 
In article .net,
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 $$$.


yea, and the price has dramatically increased in the past year or so.

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?


sure. generally it's 2mm thick optical glass that's typically a 2" or
3" square piece and you'll need to cut it to fit the camera.

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)?


you can, but the focusing might be adversely affected.

To clarify, I want to "see" IR images real-time in the viewfinder, not
post-process the image data to reveal the IR.


that's exactly what you'll get.

nospam September 25th 08 09:31 PM

Infrared photography
 
In article
,
Pat wrote:

The other option is to just buy the right camera, something like the
old Canon EOS 20Da. The "a" designates it as a astronomy camera and
it doesn't have the filter. I think it's been discontinued but you
can probably find one if you sniff around.


or the fuji uv/ir camera

If you go IR, you might also want to buy an older lens. Some of the
older ones had an IR mark on the focus ring so you could adjust the IR
focus (which isn't the same as the visible light focus).


that helps too

nospam September 25th 08 09:31 PM

Infrared photography
 
In article , bino
wrote:

The problem is that you won't see an IR picture per se, as the image
requires post processing to be anything but a dark red image. If your
camera has a B&W mode, that would be helpful, but the image will still
require post processing.


false.


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