Infra-red with Canon XTi - very disappointing

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Camera: Canon XTi, Lens : EF 28-135 IS, Filter Hoya R72 - on very sturdy tripod.<br>

This lenses has infra-red indeces, but the manual describes them for infra-red film, and the assumption it will work on digital XTi is not right. Focusing is inconsistent ; if I rely on these red marks on the lens , sometimes I get some focus, most of the time - just blur. The data sheet for R72 depict a transition diagram - the MAX plateau starts at 800nm and keeps going till at least 1100 nm - but the body has IR filter on top of the sensor, and the lens's manual says the red index marks are adjusted for 800nm - therefore, I can't estimate in every single case, what the spectrum is - that is, how much 800nm, how much of 900nm and 1000nm light is present.<br>

Anyhow, it is very tiresome to find the right IR focus correction for this lens and for this XTi (400D). I ordered and wait for Canon EOS TI - film based and then will try with ILFORD SFX 2000, the same lens and Hoya R72 - it should work better. Somebody suggested EOS 20A has no IR filter on the sensor ? Any help or suggestions for IR with EOS- s film or digital ?<br>

Thank</p>

 

<p>There are companies that remove the `AA` `IR` filters converting the digital to IR body. Google or search photonet as there have been many threads..:)</p>

<p>Not sure but may help :)<br>

http://folk.uio.no/gisle/photo/ir.html</p>

 

<p>Many thoughts and suggestions, in pretty random order.</p>

<p>Canon is famous for having some of the best IR blocking filters in the industry. This goes back to the 2001-2003 timeframe, when Nikon users were having to buy expensive hot mirror filters to deal with the IR. This is a "good thing", it lead to Canon having excellent skin tones, fabric colors, and plant colors. On a modern Canon, the IR sensitivity is so low that your picture is dominated by the wavelengths from about 700-750nm. There's no 800-1000nm to speak of. You should not be having focus problems. Are you attempting autofocus with the R72 on the lens?</p>

<p>Complex zoom lenses tend to be poor IR performers. They have more focus shift with IR than simpler lenses, are less sharp, less contrasty, and more prone to flare problems. The anti-reflective coatings on most lenses are only made to work with visible light, they actually increase reflections on IR. Simple lenses are best. Old Nikon or Pentax 20mm f4 on a Canon adapter...</p>

<p>The Canon 20 variation you're thinking of is the 20Da, a camera modified by Canon for astrophotography. There were rumors and wishful thinking about it having infrared sensitivity, but the reality turned out to be the opposite. The new filter passes abour 3x more h-alpha 656 nm light (important for astrophotography) than the stock 20D filter, yet blocks even more 700nm and above infrared than the stock 20D.</p>

<p>You are setting yourself up for another disappointment with the Ilford film. SFX200 is an "extended red sensitivity" film. Its response peaks at 730nm, and is down to zero at 770n. It will barely register with the R72 filter: exposures will be long and unpredictable. In short, you're going to duplicate your XTi failures on film.</p>

<p>The 800nm focus mark is really only useful with Kodak or Maco IR films. If you can get some Maco, give it a try. Otherwise, if iIR is important to you, get a second DSLR and have it modified for full time IR use.</p>

<p> </p>

<p>Well, thanks, but for now I'd prefer to keep XTi as it is - I expected to find a way to do IR on it without major modificatiins. There must be a way to achieve a better focus on XTi with EF 28-135 lens, because some (only few really) of the images are with acceptible focus.<br>

Besides, does it matter if I shoot in monochrome mode (or in preset landscate mode), with or without toning (sepia), with or without filter settings (red for ex.) as custom settings for monochrome ? I tried and not able to estimate the impact of these factors.<br>

And IR film ILFORD SFX 200 is on expensive side: around 11 bucks canandian for 24 shots - if I use it on EOS TI.</p>

<p>I have no problem focusing with my Canon 20D, or my current DLSR, The Canon 40D with a Hoya R72.</p>

<p>Its true what was said about Canons IR blocking filters and yes you can have them removed for about $400 at Lifepixel.</p>

<p>As I said though, I have zero problem focusing - ok, *IF* the camera has problems focusing, I remove the filter - focus, then gently screw on the filter a thread or two: enough that it wont fall off.</p>

<p>I dont use the markings on the lens to help focus - never have used them for anythng.I just let the camera do it but if it cant focus on the main subject due to not being near the focus point, I point the camera at the subject (having the camera set to one shot so it wont try to re-aquire focus lock), focus then re compose the shot. Maybe turning off auto focus once I have the camera focused on what I want it to.</p>

<p>Using a decent (fast) lens of course helps reduce the shutter speed compared to using a not so fast lens. The fast lens is a big help in IR photos IMO.</p>

<p>You indicate going to IR film - can you get it developed locally? Or do you plan on developing it yourself?</p>

<p>Chris, Joseph and others: Thanks for the help: if I understand correctly, then in order to avoid new expenses, I should return Hoya IR72 and replace it with not so dark red filter - one that should work better with film EOS TI + ILFORD SFX 200, and will not give strong IR, pronounced effect on unmodified EOS XTi.<br>

The URL from Norway is very usefull, but EOS 300 D is mensioned there as IR converted - may be in the next 2 years I will do the same to my XTi.</p>

<blockquote>

<p>And IR film ILFORD SFX 200 is on expensive side: around 11 bucks canandian for 24 shots - if I use it on EOS TI.</p>

</blockquote>

<p>I didn't even know they make 24 shot rolls (except the sample stuff).<br /> Try Rollei IR 400 and Efke IR 820. Also, Rollei 400S has some IR sensitivity. Someone even said it's the same stuff as more expensive ir-version but I can't find the source right now.</p>

<p>Exposures will be long(ish). Bracket and take notes.</p>

<blockquote>

<p>Besides, does it matter if I shoot in monochrome mode (or in preset landscate mode), with or without toning (sepia), with or without filter settings (red for ex.) as custom settings for monochrome ? I tried and not able to estimate the impact of these factors.</p>

</blockquote>

<p>I'd just shoot RAW and come up with a preset that takes you to the ballpark (both b&w and fake color). I don't trust the in-camera processor to do a good job with light it was never meant to see.</p>

<p>You can try different filtrations but R72 is The basic ir tool. It works with SFX200 but exposures will be rather long. I wouldn't return it just yet.</p>

<p>Derek:<br>

<em>"I dont use the markings on the lens to help focus - never have used them for anythng.I just let the camera do it ... "</em> - yes, buit don't we have to correct the focus due to the IR light different wave length ?<br>

<em>"can you get it developed locally? Or do you plan on developing it yourself"</em> - here in Ottawa there is one decent lab that will process them - when I try ILFORD SFX or any of the other films suggested by others.<br>

Anyhow, I will try 1. manual focus on visible light, 2. lock focus 3. put IR72 on 4. shoot with different speeds and will think again - in the next 3 days we expect rain in Ottawa, so by the weekend if we are lucky . . .</p>

<p>Keri:<br>

correction: ILFORD SXF 200 for 35 mm has 36 exposures (not 24 as I said), and yes, I will research about 'Rollei IR 400' and 'Efke IR 820'.</p>

<p>Like the others, I have had no serious problems with the R72 filter or the Canon (on a 20D). Many of the lenses I use don't have the IR mark anyhow, but if you stop down a little, everything seems to turn out ok. I find the results to be very similar to my old Ektachrome IR film (I still have 5 outdated rolls of it, but it is E-4 processing, alas.) Of course the Ektachrome was to be shot with a yellow filter, although a red filter produced stunning visual effects for fun.</p>

<p>There are issues that have to be addressed, and some lenses have "hotspots" and are unsuitable for IR. A somewhat out of date, but still very useful, discussion of some of the issues by Gisle Hannemyr can be found at (<a href="http://folk.uio.no/gisle/photo/ir.html">link</a> ). More by Bjørn Rørslett at (<a href="http://www.naturfotograf.com/irstart.html">link</a> ).</p>

<p>I've personally never have adjusted focus due to the IR light different wave length - dont know if others have (when shooting digital) - in PS after doing any manipulations I then sharpen.</p>

<p>I honestly dont know if a 'properly' IR focused image compared to my way of doing it would get different results since I've never even tried to adjust the focus. Not all my lenses have those marks anyway so I wouldnt be able to adjust properly.</p>

<p>SInce you have access to a lab that will develop that film thats great - less to go wrong(?) compared to developing yourself. I have not ever shot IR film but like to at some point before ALL ir film is gone.</p>

<p>Now that summer is (almost) here, I plan on getting a lot more ir photos. But to cheat a wee bit, I also have a Canon G5 that was modified by Lifepixel that I can use as well as my Canon 40D with a R72 filter.</p>

<p>FYI you can rent infrared-modified camera bodies if you only need them occasionally. These guys have them, and other people might as well -</p>

<p>https://www.lensrentals.com/rent/canon-eos-5d-infrared/for-canon</p>

<p>There's other information there, like a list of recommended IR lenses, and some links...</p>

<p>There is also PS enhancement for a lil extra help. not the same, but :)<br>

http://www.thelightsright.com/TLRFauxInfrared</p>