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Old September 19th, 2006, 09:48 AM   #1
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some suggestions for infrared

maybe some of you folks can help me with my infrared attempt. I have a DVC30 which has infrared mode, but like all camcorders now, they lock out the ability to stop down the lens so you can't use it during the day.

I have a letus35a which I use and canon lens's to stop down the light. Now I can shoot infrared video during the day. I'm looking to get a bit better contrast in the video. this clip I used a 100mm f2. I've since acquired a circular polarizing filter which also helps in knocking down the light and taking some of the glare out. Not sure what else to try besides shooting at different times of the day. suggestions?

http://media.putfile.com/Trees-62
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Old September 19th, 2006, 10:32 AM   #2
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Hi Michael,

I was wondering, are you using an infrared filter to block out any non-infrared light? I was thinking about experimenting with some of these.

Cokin certainly makes some (COKIN A INFRARED 89b A007) and the filter holder to fit onto the front of the slr lens of the adapter or even the camcorder lens itself are remakably cheap.

As a side note, slr filter holders also allow the use of cheap and easy lens hoods too - cromatek does a goody. These can be picked up for a few quid off the 'bay.

cheers

Dave
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Old September 19th, 2006, 12:50 PM   #3
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I've tried the infrared filter, the problem is that my dvc30 only shoots in color so what you end up with is a red image which I find is nearly impossible to expose correctly. but with the dvc30, it has the IR mode which I have no idea what it's doing inside the camera but it makes a loud clunk and I get black and white which allows me to expose the shot properly, the problem with that is not being able to dial down the iris. so that's where I use the letus and canon lens's. but i'm wondering if I might get better results getting a filter in front of the canon lens???? don't know. don't know what the GG is doing to the IR light either. Basically just messing around trying to make it look good with no idea how everything is interacting.
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Old September 20th, 2006, 09:43 AM   #4
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So you're trying to stop down without using an infrared pass filter, does your cam have one built in?

I only ask because I'm guessing that the night mode is designed to be used where there is no visible light so it probably just removes the existing ir block filter in the camcorder and fixes the aperture wide open. So using this in the day will mean a mix of visible and ir light on the ccd - hence over exposure.

I was going to get a cheap ir pass filter and have an experiment with it. My panasonic seems to pick up remote controls so I' m geussing it's capable of picking up the ir, but this will require blocking the visible too.

Another possibility/ apart from dialling down your slr lens whilst using the adapter is to make a physical aperture for you camcorder lens. There is a product called a lensbaby (a funny creative slr lens) http://www.lensbabies.com/
which does this kind of thing where the iris is on the outside of the lens, changing it requires removing a disc with a hole cut out and replacing it with a disc with a different size hole. Possibly a lens cap or 2 could work.
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Old September 20th, 2006, 02:15 PM   #5
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hmmm, good point. I might be mixing visible with invisible. You can see the tell tale signs of the infrared but it's not quite the same. I think i'm going to try a filter on the front of the letus and see if that makes a difference.
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Old September 21st, 2006, 11:52 AM   #6
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InfraRed

Hi,

I have a Sony HDV-HC1 and have produced some great IR film using the nightshot mode with a 1000nm IR filter on it during the day.

The nightshot must be opening the aperture wide-as-possible to let all light in and super-boosting the gain on the chip. There is a warning in the manual not to use the mode in daylight however with the IR filter on it works a treat. The IR filter lets so little 'normal' light through it appears opaque so it's miles better than a polariser or ND. You also get some wierd and wild affects from foliage and stonework, it's worth getting one just to see this...

I have not tried tagging my Letus onto the front of this arrangement as I have not needed to (I can do focus pulls without the Letus just using the zoom ring which is another reason that leads me to believe the aperture is wide open).

I got my 37mm IR filter on Ebay.


Regards, Nick.
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Old September 24th, 2006, 10:44 AM   #7
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Ok, bought an IR filter, it's a bw 850nw something filter. I put it between the camera and the letus. I only choose this route as I thought that I may want to use it without the letus. anyway, this was the ticketet. my previous attempt was mixing both lights.
I can use my letus to step down the light (still too bright even with the filter in broad daylight using just the filter and the camera). I can use all my canon lens's which is cool. The contrast is MUCH better than my previous attempt. foliage pops much better. it's very cloudy today so I'm not going to bother shooting anything. But the next sunny day we get, i'll take some footage and post it. Thanks for the input.
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