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12/30/2004 03:58:22 PM · #1 |
I have seen a lot of people asking for information about this mod to turn your D60 or D30 into an infrared camera, and there isn't much information about it out there. I have performed this mod, and placed step by step instructions on my webpage:
//www.photo-location.com
Enjoy! |
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12/30/2004 04:11:50 PM · #2 |
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12/30/2004 04:18:10 PM · #3 |
Originally posted by jrs915:
I have seen a lot of people asking for information about this mod to turn your D60 or D30 into an infrared camera, and there isn't much information about it out there. I have performed this mod, and placed step by step instructions on my webpage:
//www.photo-location.com
Enjoy! |
Are you mad? LOL Scary indeed.
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12/30/2004 04:32:40 PM · #4 |
:) Mad??? not really, just wanted an IR camera.
I'd say it was a bit scary, and probably not for someone who hasn't taken much apart in their lifetime, but it's really not too bad.
The most difficult part was getting the filter cut to the right size, other than that, it's basically just screwing and unscrewing :) |
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12/30/2004 04:42:06 PM · #5 |
How does the performance compare to just using an IR filter in front of the lens w/o removing the filter in front of the sensor?
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12/30/2004 04:45:53 PM · #6 |
That's a great question...
The filter that is in front of the sensor blocks almost all of the infrared light to the sensor. So, if you're putting an IR filter on front of the lens, it will work, but you are looking at shutter speeds of ~5-10 seconds (even at f1.8) in order to get enough IR light hitting the sensor.
Also, many lenses will produce a "hotspot" or a bright white spot in the center of the image. This method does not produce that hot spot, although I did see it in a few images i shot, I think it was some sort of flare.
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01/01/2005 07:47:44 PM · #7 |
A center bright spot might also be caused by stray light entering through the viewfinder. Make sure to cover up the eyepiece during longer daylight exposures.
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01/01/2005 10:37:31 PM · #8 |
That's correct, but when shooting IR, there are certain lenses that will produce the hotspot no matter if the eyepiece is covered or not.
I believe it has something to do with internal reflections of the light. I also heard that it can have to do with the coating they put on the lens when it is manufactured. |
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01/02/2005 12:10:15 AM · #9 |
Originally posted by jrs915:
That's correct, but when shooting IR, there are certain lenses that will produce the hotspot no matter if the eyepiece is covered or not.
I believe it has something to do with internal reflections of the light. I also heard that it can have to do with the coating they put on the lens when it is manufactured. |
This may be related to the "great red spot" effet sometimes seen shooting in visible light. It's caused by light reflecting off the sensor back into the lens, off the iris blades, and finally back to the sensor. Sometimes the shape of the aperture is apparent in the outline of the spot.
The fact that the spot is normally red tells us that at longer wavelengths, the effect is more pronounced. In IR, we'd expect it to be worse, then.
It would be interesting to know if the same lenses that are "bad actors" for IR work are the same ones that exhibit the great red spot effect in visible light.
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01/02/2005 08:29:30 AM · #10 |
That's interesting kirbic, but I don't really understand why some lenses would have the problem while others don't...
Unless the lenses have some sort of special coating on them, light is going to reflect off the sensor the same way. So any stopped down lens would have the same problem |
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01/02/2005 09:10:08 AM · #11 |
Originally posted by jrs915:
That's interesting kirbic, but I don't really understand why some lenses would have the problem while others don't...
Unless the lenses have some sort of special coating on them, light is going to reflect off the sensor the same way. So any stopped down lens would have the same problem |
Not necessarily. Remember that the path of the light rays will be affected by the rear elements (those behind the iris) of the lens. Each lens has a different set of elements, and the light passes through them three times.
Different cameras act differently as well. How susceptible a camera is depends on the characteristics of the sensor and/or IR cut filter. Example is the Kodak SLR Pro 14, which has higher reflectivity of the IR cut filter because it uses an "off-the-sensor" TTL metering system. The higher reflectivity means more "red spot" and in fact this camera is observed to have a worse problem than most.
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