Reply to thread

Message

<blockquote data-quote="BackdoorArts" data-source="post: 256815" data-attributes="member: 9240">When a camera is converted for IR they remove the IR filter from the stack and insert a filter that removes visible light beyond a particular wavelength (720nm is the norm, but longer wavelength filters are available which will let in more of the visible light).&nbsp; The sensor now is exposed to IR light instead of visible and metering occurs normally, only using light in the IR spectrum.&nbsp; You can also convert to &quot;Dual Spectrum&quot; which removes the IR filter but does not insert a visible light filter, essentially adding IR light to the light you get already.&nbsp; This can make for interesting effects in certain situations depending on the blend, but can be problematic for small apertures since focus calibration on each wavelength tends to be a little different and a narrow depth of field will possibly lead to one spectrum being slightly out of focus (depends on which band is used during the camera/lens calibration).&nbsp; With dual spectrum cameras folks will usually mount external filters on the lens (like your UV filter that you really don't need since there's one in the filter stack inside) removing the IR for normal use, or the visible spectrum for IR use.&nbsp; This is nice because you have a camera that can still be used normally, but also as an IR camera at varying wavelengths.&nbsp; In hindsight I wish I had done this conversion, and may convert my D90 this way in the future.&nbsp; And btw, you can also go &quot;full spectrum&quot; which removes the UV filter as well.&nbsp; Lots of folks use Lifepixel for their conversion.&nbsp; I used Kolarivision and am very happy.&nbsp; Here's a link to their list of conversions.&nbsp; It might help you understand what's what.&nbsp; <a href="http://www.kolarivision.com/filterchoices.html" target="_blank">Infrared Filter Choices | Kolari Vision Infrared</a></blockquote>

[QUOTE="BackdoorArts, post: 256815, member: 9240"] When a camera is converted for IR they remove the IR filter from the stack and insert a filter that removes visible light beyond a particular wavelength (720nm is the norm, but longer wavelength filters are available which will let in more of the visible light). The sensor now is exposed to IR light instead of visible and metering occurs normally, only using light in the IR spectrum. You can also convert to "Dual Spectrum" which removes the IR filter but does not insert a visible light filter, essentially adding IR light to the light you get already. This can make for interesting effects in certain situations depending on the blend, but can be problematic for small apertures since focus calibration on each wavelength tends to be a little different and a narrow depth of field will possibly lead to one spectrum being slightly out of focus (depends on which band is used during the camera/lens calibration). With dual spectrum cameras folks will usually mount external filters on the lens (like your UV filter that you really don't need since there's one in the filter stack inside) removing the IR for normal use, or the visible spectrum for IR use. This is nice because you have a camera that can still be used normally, but also as an IR camera at varying wavelengths. In hindsight I wish I had done this conversion, and may convert my D90 this way in the future. And btw, you can also go "full spectrum" which removes the UV filter as well. Lots of folks use Lifepixel for their conversion. I used Kolarivision and am very happy. Here's a link to their list of conversions. It might help you understand what's what. [url=http://www.kolarivision.com/filterchoices.html]Infrared Filter Choices | Kolari Vision Infrared[/url] [/QUOTE]

Verification