Infrared Conversion

<p>Hello there! <br>

I am 18 years old, and have fallen in love with Infrared Photography. I have been involved with photography for several years, starting with black and white film, then moving to infrared film. I took the leap to digital about two years ago to save money on film, chemicals, and darkroom rental. I have been taking infrared photos with a Hoya R72 filter and a tripod, sometimes reaching into the several minute range of exposure. When doing some research on infrared conversion, I have found that shutter speeds are significantly faster once the camera is converted. I absolutely love "tinkering" with my equipment, and having already converted 3 Canon FD lenses to work with my EOS body with nothing but a pair of pliers and superglue, I believe I have the skill to do at least some basic modifications to a camera on my own. I found a tutorial on converting a camera to IR at home, by simply removing the hot filter and replacing it with an IR filter. My question is this. If I were to gut my camera, remove the hot filter, and then put it back together without adding the IR filter, could I get equal results by just sticking my Hoya R72 on the end of the lens like I am currently? I realize I wont be able to look through the viewfinder, but in terms of exposure times and image quality, would it be the same? <br>

Any advice will be very helpful!<br>

JonPaul</p>

<p>Yes, I believe that many people do take infrared photos by removing the filter from their camera and then putting an IR filter on the front of the lens. I don't see any reason why this would give significantly different results from an IR filter later in the optical path (inside the camera), but others might.</p>

<p>I used to use an R72 filter on an unmodified camera, the only problem with that approach is long shutter times. The high Av value frequently cause tree's and such to not look so sharp. I have since picked up on EBay a modified 40D. I really prefer the modified body, but if you can't shell out the $500 or so, then yeah, just use the R72 filter. What body are you using?</p>

<p>I am using a Canon T1i. My thought is to take it apart and remove the hot filter, so that my exposure times would be more manageable, but i could still shoot non-infrared shots as well. What do you think would be the effect on the color images if the hot filter was not in place?</p>

<p>Probably not that much of an effect on regular photo's. But I would not remove the hot filter, I am too afraid that I might damage the sensor or other vital electronic components. You can always up the ISO sensitivity to 1600 or even 3200 to get shorter exposures.</p>

<p>Also remember that there is a *lot* of post processing with IR. When you take the photo, out of the camera it just looks like a red photo. Here is an example with no post processing:<br>

<a href="http://www.gregoryferdinandsen.com/Images/SAV2009/Savannah_Forsyth_Park_R72_Jul09_004.jpg">http://www.gregoryferdinandsen.com/Images/SAV2009/Savannah_Forsyth_Park_R72_Jul09_004.jpg</a></p>

<p>I shoot a little differently. I have tried shooting the way you do, leaving the WB how it is, but I always end up with my leaves and my sky being too close in color for me to make anything of it. I'm assuming you swap channels around is Photoshop? Right now I usually take a custom white balance off of random foliage and use that. Would I get better results shooting the way you do?<br>

You can see one of my shots, unedited, in my photos. <br>

It's not letting me post it here...</p>

 

<p>I shoot with the white balance of 2700 Kelvin. Then I apply auto-levels in PS, then I swap the channels. After I swap the channels, I go into Hue/Saturation and really bring down the saturation of the Magenta's, that give the foliage a white-ish look.</p>

<p>Alright I will try that. Thanks!<br>

 </p>

<p>Post a picture show how it came out</p>

JP, when you remove "hot filter" you shift focal plane. If enough lens focusing travel around infinity remains, go for it. If

not, you will have to glue back equally thick glass sheet, preferably coated. Standard microscope slide cover is usually

a good choice. Good luck!

<p>This link: http://www.lifepixel.com/tutorials/infrared-diy-tutorials/canon-20d shows how to convert the Canon 20D to see Infra Red.</p>

<p>I have been reading Photonet for some time, but now seemed a suitable time to join so as to offer some help.<br>

JonPaul, you ask what would be the effect on color images if the hot mirror was not in place. The effect is substantial and in scenes under direct sunlight the effect is dramatic because a large amount of IR is reflected from many surfaces, especially plants. In my experience choosing an appropriate WB cannot correct properly for this This may be because the IR affects to some extent the green and blue channnels in addition to the red. I imagine the extent depends on the manufacturer's choice of filter for the Bayer array. <br>

<br />If you choose to remove the the hot mirror you would be well advised to replace it with glass of similar thickness, as recommended by Brano Kovacevic. Of course if the replacement glass has a refractive index different from the removed filter it will not correct the focus error fully.<br>

If you shoot with the R72 (IR pass) filter on the lens of a DSLR you cannot see to compose and focus. If you compose and focus without the filter and then fit it, the focus will be compromised because IR is not focussed in the same plane as visible light. <br>

For that reason I suggest you select a camera with live view for conversion. This will enable you to compose and focus accurately with the R72 filter in place.<br>

See a following post for more information.<br>

Regards,</p>

<p>Charlie</p>

<p>A continuation of the above.<br>

I converted a Samsung NX10 by removing the hot mirror and AA filter. In the case of this camera the AA filter also blocks some IR. I now shoot IR with the R72 filter on the lens and exposure times are comparable to shooting in visible light. The camera's exposure measurements are accurate in shade, but in direct sunlight foliage is overexposed and so EC needs to be applied.<br>

I sometimes shoot this camera in visible light with a hot mirror (B+W 486M filter) on the lens instead. Even this expensive filter passes a lot of IR and I have to correct in PS/ACR to get realistic color. My solution is to use the dropper tool on a part of the subject that I know to be neutral (grey/white). Many scenes will not include a neutral element, but it is easy to place a grey card suitably for just on shot in a series and then apply the same correction for all the shots.<br>

This technique might work for processing shots in visible light on a converted camera without the a hot mirror on the lens, but the required correction would be more extreme. <br>

<br />As far as manipulation of the RAW files for a desired result is concerned, feel free to experiment!<br>

Good luck with the conversion!<br>

<br />Regards,<br>

Charlie</p>

<p> </p>