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-   -   Infrared Filter Examples (https://www.dvinfo.net/forum/open-dv-discussion/20522-infrared-filter-examples.html)

Samantha Constant January 28th, 2004 05:06 PM

Infrared Filter Examples
 
Does anyone have, or know where I can find, some examples of Video shot with an IR Filter? I've found countless sites for Infrared Digital Still Photography but nothing with examples of actual Video. I'm looking at the Hoya R72 but want to see it in action first. Thanks in advance for any help!

George Brackett III January 28th, 2004 06:31 PM

http://www.kleptography.com/s-notes-infrared72.htm

Samantha Constant January 29th, 2004 11:44 AM

Infrared Filter Video Examples
 
Thanks for the link but I'm not having any trouble finding IR shots with a digital still camera; I'm looking for examples of video and I can't find any. I'd likt to see the IR filter used in filming motion.
Thanks!

Rolland Elliott February 14th, 2004 09:14 AM

You need a modified digital camcorder to shoot IR
 
You need a modified digital camcorder to shoot IR.

I did this once with an old JVC Mini DV camcorder. You have to open it up and replace the green/blue IR block filter with a clear piece of glass or black IR tranmitting glass.

The results look just the same as the sample IR still camera shots on the above web site. Amazing contrast in a glowing B&W footage. Well worht the trouble.

You can't just pop an IR filter on any mini DV camcorder. It has to be modified. Sorry

Helen Bach February 14th, 2004 07:20 PM

The IR blocking filters used in front of CCD(s) are not perfect - they do let some near IR through, often a surprising amount. An easy way to check this is to shine your TV remote into the lens of your camera. If you see the IR transmitter light up in the viewfinder, your camera is 'seeing' some IR and it will work with an R72, for example, without any modification. Both my TRV900 and VX2000 can be used in IR, though I use B+W 092 and 093 filters instead of Hoya.

Any 'Nightshot' camera will shoot IR ('Nightshot' is the temporary removal of the IR blocking filter), but all current consumer production models have a link to open the aperture and turn the gain up when Nightshot is activated. This prevents the Nightshot camera from being used to 'see through' clothing in the strong IR of bright sunlight. It is possible to de-activate the microswitch that causes the aperture to open and the gain to be increased when Nightshot mode is activated. This means that you have a camera with a switchable IR blocking filter. It may also be possible to move the switch part way, so that the filter is moved, but exposure control has not been disabled.

On Sony Nightshot cameras made before 12 August 1998, full exposure control is available in Nightshot mode. Sony were very embarassed to discover that these cameras could be used to 'see through' clothing, so they added the microswitch.

In general the CCDs on Sony Nightshots are a little more sensitive to IR than other CCDs. I think that they are sensitive out to 1400 nm. Kodak High Speed Infra-Red film (HIE) is only sensitive to about 1000 nm, and that is the most sensitive of the easily available films.

There are examples of Nightshot video in daylight (as opposed to still camera images) on the web that show the effect of an R72, for instance, but all the ones I could find were of see-though clothing, so I'm not going to post the dirty sneaky links here. However, the image from a video camera is going to be remarkably similar to that from a digital still camera.

Best,
Helen

Rolland Elliott February 14th, 2004 07:51 PM

not all cameras are the same.
 
"However, the image from a video camera is going to be remarkably similar to that from a digital still camera."

This is a vague generalization that is often not true.

For instance the link below
http://www.kaya-optics.com/images/kaya_massh_gss_01.mpeg
(above link shows very blurry ladies in swimming suits hardly exciting or provacative if you ask me)

Doesn't look anywhere close to IR B&W film. It has a nasty green tint and the contast is very low. I've seen pictures from modified Sony cameras that have the Blue Green filter removed and they have a purple blue color cast. Pretty ugly effect if you ask me.

My modified JVC camcorder had a deep read color cast, but when shot in B&W mode yielded images very much like Kodak B&W film, minus the grain. Of course that camera died years ago after it ate one to many mini DV tapes of mine.

I just ordered a cheap Canon ZR80 for $330 that I will modify. I think the Sony's would of been easier to modify, but they are also more expensive and take different batteries. I already have a Canon Mini DV camcorders and like the fact that accessories are compatible.

It is odd that I haven't seen any infrared footage made from a modified camcorder I think the effect is soo cool.

Peace, Rolland


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