A Photography forum. PhotoBanter.com

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

Go Back   Home » PhotoBanter.com forum » Digital Photography » Digital Point & Shoot Cameras
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

Infrared photography



 
 
Thread Tools Display Modes
  #11  
Old September 25th 08, 10:46 PM posted to rec.photo.digital,rec.photo.digital.point+shoot
bino
external usenet poster
 
Posts: 82
Default Infrared photography

"nospam" wrote in message
...
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.


You got some facts jackass? Experience? I've shot IR film and IR digital.
The red filter makes the color sensor see red. Period.

  #12  
Old September 25th 08, 11:12 PM posted to rec.photo.digital,rec.photo.digital.point+shoot
nospam
external usenet poster
 
Posts: 21,693
Default 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.


You got some facts jackass? Experience? I've shot IR film and IR digital.
The red filter makes the color sensor see red. Period.


except that the blue pixels also pass infrared light and depending on
the camera, the white balance, the strength of the infrared filter and
the raw processing, the results can be virtually anything.

i've used a couple of digital cameras for infrared and modified one of
them myself. none of them produce red images out of the camera. on
the camera's lcd screen and the jpegs they produce, the result is b/w.


if anything, there's a mild greenish cast, perhaps because the camera
is boosting green due to the weak response of the green pixels with
infrared light. the very same image when shot raw and processed via
adobe camera raw has an entirely different appearance than with nikon
or canon's software.

saying that it will always be red is simply false.
  #13  
Old September 26th 08, 05:27 AM posted to rec.photo.digital,rec.photo.digital.point+shoot
[email protected]
external usenet poster
 
Posts: 220
Default Infrared photography

In rec.photo.digital bino wrote:
| "nospam" wrote in message
| ...
| 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.
|
|
| You got some facts jackass? Experience? I've shot IR film and IR digital.
| The red filter makes the color sensor see red. Period.

Who said anything about a red filter ... in this thread?

Actually, I would recommend a IR-passing filter (e.g. type 89) on the lens
after the IR-blocking filter is removed. The sensor (with a replacement
all-passing filter to keep the optics consistent) will pick up IR in other
colors. This is because the color separation of the sensor is not designed
to discriminate IR (and hence why an IR-blocking filter needs to be added
in the normal case). The red channel will get the most IR. The blue channel
will get a lot. The green channel will get some. And these will vary by
what IR wavelength is involved. So you will get some false color effects.
Directly viewing the image on the camera screen will give some funny reddish
colors for sure. Post processing can then give you the effets you want if
you were using the correct lens-front filter to begin with (type 29 for some
effects, type 89 for others, and type 87 for yet others). In some cases the
desired effect is achieved by making everything monochrome. In other cases
the desired affect is a color product derived from adding or subtracting the
various color channels. Additionally, multiple shooting of a stationary
subject with different lens-front filters (the above plus 25, 23, 15, 12, and
none at all) can give you multi-channel info to even be able to derive the
original visual image unaffected by infrared (with the correct formula).

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |
  #14  
Old September 26th 08, 05:40 AM posted to rec.photo.digital,rec.photo.digital.point+shoot
[email protected]
external usenet poster
 
Posts: 220
Default Infrared photography

In rec.photo.digital Pat wrote:

| There are some good step-by-step instruction out there for removing
| the filter. You can leave the filter off, but IIRC you need to
| replace it with small shims to keep everything in place.
|
| If you use a IR filter, you then have to have extraordinary long
| exposures because you still have the IR filter in place taking out
| most of the IR.
|
| 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.
|
| 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).

Or you can pay someone else to do the conversion for you:

http://www.lifepixel.com/
http://www.spencerscamera.com/

--
|WARNING: Due to extreme spam, googlegroups.com is blocked. Due to ignorance |
| by the abuse department, bellsouth.net is blocked. If you post to |
| Usenet from these places, find another Usenet provider ASAP. |
| Phil Howard KA9WGN (email for humans: first name in lower case at ipal.net) |
  #15  
Old September 26th 08, 06:04 AM posted to rec.photo.digital,rec.photo.digital.point+shoot
DaveC
external usenet poster
 
Posts: 15
Default Infrared photography

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.


Seems straightforward (notice the absence of the term "simple").

Can you give a URL for such a piece?

The proper thickness of the replacement glass should be...? Should it be the
same thickness as the filter removed from the imager?

Thanks,
--
DaveC

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

  #16  
Old September 26th 08, 06:11 AM posted to rec.photo.digital,rec.photo.digital.point+shoot
Eric Stevens
external usenet poster
 
Posts: 12,272
Default Infrared photography

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.



Eric Stevens
  #17  
Old September 26th 08, 06:57 AM posted to rec.photo.digital,rec.photo.digital.point+shoot
nospam
external usenet poster
 
Posts: 21,693
Default Infrared photography

In article .net,
DaveC wrote:

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.


Seems straightforward (notice the absence of the term "simple").


if you know how to cut glass it should be fairly easy. however, opening
up the camera to replace the filter is usually not easy at all.

Can you give a URL for such a piece?


here's a few:
http://www.alpineastro.com/filters/filters.htm
http://www.controloptics.com/product_colorglassfilters.htm
http://www.edmundoptics.com/onlineca...cfm?productID=
1918

The proper thickness of the replacement glass should be...? Should it be the
same thickness as the filter removed from the imager?


it should. if it's not that close, you might lose either infinity
focus or close-up focus, but stopping down should compensate for that.
depending on the camera, the autofocus might need adjusting.

the other problem is the only way to know how thick a filter to get is
open up the camera and measure it. it varies depending on the camera,
and sometimes it varies with the *same* camera, depending on the
revision. i've also heard of using microscope slides to match the
thickness.
  #18  
Old September 26th 08, 10:29 AM posted to rec.photo.digital,rec.photo.digital.point+shoot
carlislestamford
external usenet poster
 
Posts: 8
Default Infrared photography

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

  #19  
Old September 26th 08, 03:02 PM posted to rec.photo.digital,rec.photo.digital.point+shoot
Don Stauffer
external usenet poster
 
Posts: 237
Default Infrared photography

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,


You will not SEE the IR regardless of whether the filter allows a live
preview.

A filter only allows or blocks a given wavelength- it does not CONVERT
it from one wavelength to another.

In effect, the digital camera does a conversion, but provides three
channels of color info. The read channel does not maintain spectral
information. All reds are the same. What the result is is a "false
color" picture. You are not viewing real infrared radiation when you
view a print or a viewfinder image taken with an IR-enabled camera.
  #20  
Old September 26th 08, 03:31 PM posted to rec.photo.digital,rec.photo.digital.point+shoot
DaveC
external usenet poster
 
Posts: 15
Default Infrared photography

You are not viewing real infrared radiation when you
view a print or a viewfinder image taken with an IR-enabled camera.


Ah, yes, of course you're correct.

Isn't language a trip-up? "No, you misunderstood what I meant to say"... :-)

Thanks,
--
DaveC

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

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Infrared photography DaveC Digital Photography 39 September 29th 08 01:29 AM
Infrared Photography Competition Wayne J. Cosshall Digital Photography 25 December 10th 06 07:38 AM
Some more infrared photography Wayne J. Cosshall Photographing Nature 0 December 7th 06 09:29 AM
Cokin Infrared P filter for digital infrared photography Matt Clara Digital SLR Cameras 0 March 20th 05 06:36 PM
Digital Infrared Photography Suz Digital Photography 33 November 8th 04 11:44 AM


All times are GMT +1. The time now is 02:17 AM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Copyright 2004-2018 PhotoBanter.com.
The comments are property of their posters.