Digital IR Photography Using Canon 7D, 350D, and Cokin IR P007

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<p >Hi Dear PN Members,</p>

<p >I am extremely interested in Digital Infrared Photography; I have been trying to do that for sometime now without any rewarding results.</p>

<p >I’ve got the Cokin P007 Infrared (equivalent to the KODAK 89B 720nm), that I have used along with unconverted Canon 350D & 7D. I have made a simple test to see if these cameras are IR sensitive (using the TV Remote Control) and both cameras detected and recorded the IR light emitted from the RC.</p>

<p >Shot in RAW+JPG formats, using the 24-70mm f/2.8 L and prolonged exposures resulted in foliage appearing in grey tones and bleached white skies (unlike the expected result of white foliage against dark skies).</p>

<p >Even after many trials with different exposure times, f numbers, manual white balance (using the grass to measure WB), different PS manipulations and conversions, the results were unfortunately disappointing and very far from being IR.</p>

<p > </p>

<p >Few questions: </p>

<p >1. Is it my fault, the camera’s, or the IR filter that I am not getting the desired result?</p>

<p >2. Using unconverted 350D or 7D, have anyone successfully produced IR photos using the Cokin P007 IR?</p>

<p >If this is a filter problem, then I am left with the option of converting the old 350D to a full time IR camera against buying the expensive 77mm Hoya R72 Infrared Filter ($100), I am aware that with the later option I am going to lose the spontaneity due to prolonged exposures.</p>

<p >Thank you in advance…</p>

<p >Regards. </p>

<p > </p>

<p > </p>

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<p>The Cokin filter holders I've seen are pretty leaky. Unless you completely exclude visible light, you won't get a good IR effect.</p>

<p>What is this discussion about "white balance?" IR images don't have a white balance - they are monochromatic (or green). You don't get false color, as with IR Ektachrome, because that film is designed specifically for false color (with one IR sensitive layer).</p>

<p>The Nikon D100 seems to do pretty well with IR. High-pass filters got a lot better with succeeding models. My D2h has color problems with IR under incandescent light, but has limited sensitivity with an "expensive" IR filter. I do get the IR effect, however.</p>

<p>The real solution is to recycle an obsolete DSLR, and have the sensor fitted with a low pass filter. That's the only way you can actually use the camera without live view.</p>

<p>Edward,<br>

Thank you so much for your kind advise, very helpfully indeed. Its interesting to know that the Cokins are leaky!<br>

Your comment about the WB is absolutely true IMO (specially when shooting RAW), However many IR references dedicated few pages explaining how to set WB for Digital IR photography. ( For example: David Busch's Digital Infrared Pro Secrets and Deborah Sandidge's Digital Infrared Photography).<br>

Thank you again.<br>

KindRegards. </p>

<p>Edward, of course you get false color.</p>

<p>The Wratten 89B equivalent filters like the Cokin 007 pass enough barely visible red light (say 670-700nm) that this shows up very strongly in the red channel, while the blue and green channels respond more strongly to wavelengths roughly 700-730nm. (The camera's infrared blocking filter pretty much blocks anything past that point). Setting the white balance properly is critical for cameras that have separate hardware gain for the red, green, and blue channels (Nikon D2X, for example) and for cameras that apply any type of lossy compression to the raw file. It's less critical for most Canon models, you can play with the final white balance in post. Although properly set WB is useful on any camera, for checking out the false color in the review and liveview images.</p>

<p>p.s. I've been using unmodified cameras for near a decade, with an opaque filter like a Cokin R72 or RM90, and old fashioned auxilliary viewfinder in the hot shoe. Here's an old Nikon D100, Cokin R72 filter, generic eastern European finder.</p><div></div>

<p>IR contamination had long been one of larger problems of digital cameras: it caused strong color casts (flowers, fabrics) that were very difficult to correct during the post process. However, the older DSLRs that suffered from IR contamination (Nikon D2H, for example) were "good" cameras for IR without any modification. Unfortuately (for this purpose), Canon had solved the IR contamination problem earlier than Nikon, so I haven't heard of any Canon cameras since 20D that can be used for IR without modifications. Even Nikon DSLRs since D200 and D2X are unusable for IR. Remember that Canon even needed to offer a special version of 20D for astronomical photographers to capture H-alpha spectrum which is 656nm and should be called "deep red" and not "IR".</p>

<p>Considering that 350D is way more recent than 20D and that D7 is "the" most recent Canon DSLR, I'm afraid I don't think they can be used for IR without modification. IR LED on the RC is not necessarily a good tool to judge the IR capability of DSLR.</p>

<p>Heider, you're quite welcome.</p>

<blockquote>

<p>IR LED on the RC is not necessarily a good tool to judge the IR capability of DSLR.</p>

</blockquote>

<p>Akira, you're quite right. You're talking about a very bright (multiple suns worth) point source of light. Under real shooting conditions, you may still need 30 seconds at ISO 800 to get a decent picture outdoors. We'll have to wait till someone tries a 7D with a non-leaking filter to see how it works.</p>

<blockquote>

<p>Remember that Canon even needed to offer a special version of 20D for astronomical photographers to capture H-alpha spectrum which is 656nm and should be called "deep red" and not "IR".</p>

</blockquote>

<p>And Canon actually added extra IR blocking to that camera, so although it would do H-Alpha, it was even more useless for IR than the regular 20D. They didn't want a repeat of the Sony "x-ray camera" disaster, with frothing mad mothers burning ans smashing cameras in protest.</p>

<p>Heider, you are welcome. Joseph, thanks for the follow up.</p>

<p>As for Heider's result with Cokin 007 and 350D or 7D, I bet that the camera recorded an extremely narrow band in the deep red area. That's why you didn't see any characteristics of IR images (white foliage or jet black sky). Actually 007 (I also have one) and Wratten 89B equivalents pass quite a bit of visible (deep red) light and mostly used for IR images in false color rather than in B&W.</p>

<p>In order to get a good B&W IR images, you would need denser filter like Kodak Wratten 87 or 87C or their equivalents, or even denser RM90. In order to use these filters successfully, you need a camera that "seriously" suffers from IR contamination. Here is my humble example of how the unprocessed image should look in order to get a B&W IR image. Unfortunately, the sky is not jet black because I shoot it in a clouded day, but, as you see, the foliage is already fairly completely white. There are healthy amount of data in all of R, G and B channels. A slightly excessive datum in R channel caused pinkish cast, but it is almost already quite obvious monochrome IR image without any processing. The image was shoot with unmodified Nikon D40, Fuji TAC IR90 filter, Nikkor 28/3.5 lens at ISO400, f11, 10 sec.</p><div></div>

<p>Joseph and Akira, Again thank you so much for the help. </p>

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<p>As for Heider's result with Cokin 007 and 350D or 7D, I bet that the camera recorded an extremely narrow band in the deep red area. </p>

</blockquote>

<p> <br>

Akira, you're absolutely right. Yesterday I made some tests with both cameras and I wanted to share the "results" with you. It’s very obvious that the P007 filter is leaking visible light and the hot mirror is blocking the IR. I don't know if the RM90 or R72 will solve this issue. I wish somebody tired these with unconverted 350D or 7D.</p>

<p>Now, I am seriously thinking of converting the old 350D to a full time IR, (Cost is Approx $400 from Lifepixel.com), Or maybe I will do the conversion myself. I've been through the DIY of lifepixel.com, looks quite complicated. Aside from the technical difficulties, I haven't got the IR filter that replaces the hot mirror (That would cost around $200).</p>

<p>Few questions:<br>

1- Do you think that attempting to convert the camera myself is a total insanity?<br>

2- Do you think that I can get decent IR Photos by only removing the hot mirror, and using Coking P007 mounted on the lens instead of using the Standard IR filter from lifepixel.com?<br>

3- How would the camera perform without both the hot mirror and the IR filter (Cokin P007)?</p>

<p>As you can see I am not planing to invest much on IR Photography, at least for now. However I don't want to do some stupid move that I will regret later on. IR Photography can wait few more months.<br>

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Thank you so much.<br>

Regards<br>

<br /></p><div></div>

<p>So far as I understand:<br />1. if you are not confident enough of your dexterity, I, for one, would not recommend or encourage you to do that yourself. A friend of mine have succeeded in removing the internal IR block filter of Nikon D200, and another friend of mine ruined his Panasonic G1 during the similar trial. My impression is that the newer the model is, the more complicated the internal construction becomes.</p>

<p>2. yes, the sensitivity to IR should increase by several stops, but before you do that, please refer to #1.</p>

<p>3. the color balance should be shifted greatly to red. In order to get the natural color balance, you will need IR block filter like Schott BG40. Actually, an IR block (blue-green) filter and a hot mirror are two completely different ones. A hot mirror, as its name suggests, mainly blocks the "heat" range of IR and doesn't cut the IR range that yields photographic images. The filter in front of the image sensor is a combo of IR block filter (not hot mirror) and anti-alias filter.</p>

<p>I'm not going to discourage you from trying IR photography, but conversion of the camera is not enough to take pictures in IR successfully. There are some more issues to consider, too:</p>

<p>1. focus shift: you need to compensate for the focus shift in IR range after you focus in visible light (remember that "red dot" on the older MF lenses in film days?). IIRC, both Lifepixel and Maxmax (my friend asked the latter to convert his Nikon D200 and recommends the latter) will adjust the focus shift by adjusting the neutral position of the reflex mirror, but I don't know how reliable that adjustment is.</p>

<p>2. image quality: obviously the camera lenses are designed to yield good images in visible range. There is no guarantee that an expensive professional lens (like Canon "L") will perform good in IR range. On the other hand, a cheap mediocre lens can perform excellently in IR range unlike in visible range. You need to try individual lenses to find usable ones.</p>

<p>3. hot spot: even a lens that yields sharp images in IR range may show a translucent white circle with ambiguous edge in the center of the frame, which is often seen in IR images when you use an inappropriate lens. This is called "hot spot" and is caused by the irregular reflections interacting in the lens and tha camera's mirror box. A multi-coated flare- and ghost-free lens isn'T necessarily free from hot spot when you use it in IR range. Again, you'll need to test indivisual lenses.</p>

<p>I've been Nikon user and there are experts in IR (or even UV) photography in the community of Nikon users (like Joseph and Bjørn Rørslett) and you can be exposed to a bunch of info on the issues mentioned above in the community of Nikon users (Nikon forum here, for example). But personally I don't know any Canon user who is doing IR, so I'm afraid I cannot name any Canon lens that perform good in IR.</p>

<p>I am interested in Digital IR as well.<br>

Has anyone has considered the camera in this article:</p>

<p>I was searching for the Cokin filter mentioned in this article and came across this thread - thought I'd ask here.<br>

Thanks for any info.</p>

<p>I've seen comments about sharpness issues with infrared on other forums, and often the solution of checking for a red dot on "older lenses" which is the index or "witness" mark for focus position using infrared. Fine so far.<br>

But it is well to remember that the resolution of the optical system starts with a consideration of the size and location of the window of light wavelengths being used to form the image. As a general rule of thumb, the longer the wavelengths (the redder you go) the lower the resolution. This is the precise reason that scientists who want to critically look at tinier and tinier objects first to go ultraviolet, then electron microscopes. Imaging objects that are the usual targets of these devices simply is not practical with wavelengths even as "short" as green (in the 5400Å range), let alone the red and infrared (>6000Å) real estate.<br>

This is also the precise reason that reflectors for very long wavelengths (radar and radio telescopes, for instance) can be relatively approximate shapes that wouldn't stand a hope of creating an optical image, but that can, because of the long wavelengths' relative resistance to things like refraction and absorption, look into the depths of interstellar space. Everything is a tradeoff.<br>

Therefore and ergo, before getting disappointed that IR images aren't as crisp as your visual wavelength shots, bear in mind that, essentially by definition, it is not possible for them to be so. On the other hand, IR images are really really cool, and sometimes that's a happy tradeoff.</p>