Sunday, June 27, 2010

Infrared Photography; Supplemental Post - Photography with Imre - Episodes 23 and 24

I figured I'd take a quick break and write up the post for the two infrared photography videos (episode 23 and episode 24). This topic is by no means a small one, so as you saw in the video I really honed in on shooting with "regular" cameras, meaning non-IR modified, using IR filters. I would say that if you're new to infrared photography, then this is a good way to gain some experience without spending too much money. Of course if you take a liking to the realm of red, then there are lots of options to take this niche further.

If it's one piece of information I couldn't find, it's in regard to at what frequency the IR blocking filter on the sensor cuts out. As you saw in the video my E-P2 could pick up the remote control's IR "beam", but I wonder where the limit is. I'm guessing it's around 720nm, but perhaps I didn't look hard enough or this is some sort of manufacturer secret as it may be used to somehow enhance the quality of the photos the camera takes. Hmm... On the other hand, a sensor without an IR blocking filter seems to have a limit around 1,100nm (see Luminous Landscape website link below).

Now if by chance you're wondering why someone would go to the trouble and potentially expense to modify their camera or purchase an IR version, there are some very good reasons. To begin with, let's quickly examine some of the cons of using an IR filter:
  • Extra piece of very dark glass in front of your lens; forces use of long exposures; potential for flaring or minor loss of image quality
  • Long exposures increase the amount of noise in a photo; depending on the camera, this may or may not be an issue
  • Quality of filter matters; some may not cut out all visible light (although this isn't necessarily bad, as for example the Hoya R72 allows some very deep reds through and I'm thinking this could improve the image quality because an unmodded camera will definitely capture the visible light frequency dark reds at the very least)
  • Takes more time to setup and take some shots as IR filter needs to be placed on or removed from the lens
  • Long exposures mean you'll have to carry around and use a tripod
On the other hand, using an IR filter is probably the least expensive route and you can still get decent results using unmodified cameras.

At this point you're probably starting to see the pros of an IR modified camera and by the way, there are different types of modifications; removal of the IR blocking filter and removal of IR blocking filter and replacing it with an IR filter (over the sensor). At this point I recommend you check out some of the links I've posted below to discover the reasons for each type of modification. So in short, here are some pros of modified cameras:
  • More or less shoot like you would regularly; shorter exposures; less noise; potentially no need for tripod so handheld shots possible
  • Generally much better image quality than using unmodified cameras with IR filters
Indeed only two bullet points, but that first one is packed full of positive goodness. Now depending on the direction you take with the modification, professional or do-it-yourself, some cons do appear. Professional modification may be pricey and if you're the tinkering type but manage to put a thumb print on the sensor, then you're not only out of a camera, but a few bucks too as you'll likely replace it.

But let's move on to taking shots using an IR filter. As you saw in the video, although I collected my thoughts before shooting the segment by the lake, it was still unscripted and a tad rocky. Nonetheless, I roughly covered the steps and to fulfill my in-video promise, here is the general procedure I followed to take my IR shots:
  1. Without the filter, I composed the shot I wanted to take
  2. I prefer using manual focus, but really you could use auto-focus and then lock it by switching to manual once the camera finishes its task (i.e. set camera to auto-focus, then press shutter button half-way, then switch to manual focus mode but don't touch the lens focus ring)
  3. I always took three exposures with the following settings: f/4, shutter speeds of 1, 2, and 3 seconds, with sensitivity at ISO 200. Now I was bathed in bright sunlight, but depending on your shooting conditions, these settings may not do much good, so you will have to experiment a little. Here's a quick tip too if you're finding that your focus is off: simply use a smaller aperture, like f/8 or f11; keep in mind though, with a smaller aperture comes longer exposure times.
  4. Now place the filter on your lens
  5. Shoot away!
One thing I was reminded of during my on-location shoot was how difficult it can be to see the LCD screen in daylight, so taking several shots at multiple exposures almost guarantees you'll have at least one workable photo, even if you can't quite tell which shot works and which doesn't. And I'd like to add something that may aid in viewing IR photos on your camera after you take a shot or two. Perhaps try to set the white balance to as low as it will go (e.g. 2,000K), and see if that neutralizes the red tone a little. I wish this occurred to me sooner, as I would've tried it and suggested it in the video if it worked; for another day then!

I'm just starting to realize the sheer size of this post! Ok, to finalize things, my second video encompasses a quick Photoshop tutorial on how you can post-process IR photos. Indeed, shots out of he camera are very red in tone, which should be no surprise as the IR filter essentially only allows very deep reds and near IR wavelengths of light through (although there is a tad bit of color data there). The first segment in the video demonstrates false color processing and the second part shows how to process IR photos into black and white (or grayscale). In a nutshell, there are many different ways of processing these pics, so I suggest you examine some of the links below in the resources section to see what else photographers are doing. I would personally say that there is hardly a "right" or "wrong" here too. Instead, this is a matter of taste where some people love the false colored versions of the photos with those dark blue skies and pinkish (near white) foliage, or hate it and like the black and white style.

So for the next episode, I'll be showcasing high dynamic range imaging (HDRI or HDR photography). It seems to be a popular topic as I've already had two requests for it! Awesome! So have fun with the IR stuff and TTYL! L8r!

Web Resources
http://en.wikipedia.org/wiki/Infrared_photography
http://www.wrotniak.net/photo/infrared/
http://www.hoyaoptics.com/color_filter/ir_transmitting.htm
http://www.hoyaoptics.com/pdf/R72.pdf
http://en.wikipedia.org/wiki/Infrared
http://www.absoluteastronomy.com/topics/Infrared_vision
http://www.luminous-landscape.com/reviews/cameras/infrared%20dslr.shtml
http://www.microscopy-uk.org.uk/mag//artmay10/dw-s75-ir.html
http://www.dpfwiw.com/ir.htm
http://www.shotaddict.com/tips/article_How+To+Post+Process+Your+Infrared+Digital+Photos.html
http://tutorials20.com/misc/infrared-photography/
http://khromagery.com.au/ir_raw.html
http://www.smashingmagazine.com/2009/01/11/40-incredible-near-infrared-photos/
http://www.webdesignerdepot.com/2009/06/100-outstanding-and-inspirational-infrared-photos/

11 comments:

  1. I have a bit of a dumb question. If I focus my camera (Nikon D80), does it lose some of the focus when the filter is being put onto the camera? When I've screwed the filter onto the camera lens ring, the lens tends to move. I'm thinking that this may change my focus, and since you can't look through the camera when the ring is on because it's so dark, then I don't know if this is actually happening. I'm new with the IR filter and haven't used it much yet.

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  2. Hi Jacklyn! Not a dumb question at all. If you find that the lens moves or shifts inwards as you put the filter on, then there is a potential that the focus could be off... perhaps not by much though if you're using a smaller aperture and focused into the distance, but the possibility is there. I think the impact to focus would be more significant if the lens barrel rotates externally when focusing; most lenses have internal mechanisms, whereas a few rotate and shift (in and out) the front portion of the barrel (the Zuiko 70-300 is like this, using a polarizing filter is cumbersome; every time I focus the filter turns out of whatever position I set it to).

    But if the focus mechanism is internal (nothing moves or rotates on the outside of the lens) and by moving the lens you mean just pushing the "zoom" back a bit, then that shouldn't be much of an issue. Perhaps try focusing like you normally would and take a regular picture, then gently nudge the end of the lens as if putting on a filter, then take another regular picture. See if you can note a difference between the exposures; maybe try significantly changing the zoom to see how severe the change in focus is.

    Last quick thought; the focal point of near infrared light frequencies are different than that of visible light. So although a subject may be in focus for our eyes, in IR the focus may not be quite there anyway.

    Good luck with the IR shooting!

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  3. Thanks very much for the response. Part of my weekend is going to be devoted to experimenting with the IR.

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  4. Howdy. I took a couple of IR shots at a park this morning. One was much better than the other and it took some tweaking in PhotoShop to get close to what I wanted the end result to be. It's on my blog if you're so inclined to take a peek at it. Back out tomorrow, weather permitting.

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  5. I just bought a Cokin P007 IR filter and took some IR shots with my Canon 500d. The photos looked very reddish (which I think is normal) but the foliage looked very dark (not even looked light or white at all). They just like a normal shot with a red filter on.

    Is it something to do with the filter and how can this be resolved?

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  6. Hi, Daniel. Yes, a strongly red toned image is normal when using an IR filter, but what doesn't sound right is the green foliage being dark; green colors are highly reflective in near IR light, thus of course appearing almost white.

    I have a few suggestions I can offer:
    First, try this filter on a different camera if possible to see what happens (another brand if you can, like Nikon or Olympus, etc.). I'm not too familiar with the Canon 500D's response to IR light. It's possible it has a very strong IR blocking filter on the chip and as such getting that IR look is difficult if not impossible. But at least if it works on another camera, then you'll know that the Canon probably has a strong IR blocking filter, OR if you get the same result using another camera, then it could be a "bad" filter.

    Second, so if you have a "bad" filter you could try to exchange it for another one and see if the results are different (although this would be a rare occurrence in my opinion). I don't know if this is the same for everyone, but on a bright sunny day if I hold my Hoya R72 up to my eye and look at trees, the leaves are almost white. You might consider trying this to see if the filter "works" (just don't look directly at the sun!).

    Third, if you can, try using a Hoya R72 (the R72 and P007 from Cokin are essentially identical; both are based on Kodak's 89B which gives 50% transmission at 720nm). I would personally say the Hoya's are better quality, so maybe you can get results with that filter. Since I don't have the Cokin, I couldn't say myself.

    Four: Maybe this point should be higher up, but try using longer exposures and different settings. Perhaps open the lens as wide as it'll go and use a higher ISO like 800 or 1600 to get a short exposure time, and then close down to let's say f11 and ISO 200, which will increase the exposure time and see if that makes a difference.

    Hopefully that will help you determine what's going on. I did some quick research but I see that other people are using this model of camera for IR shots and the results look ok to me. I keep thinking that maybe the filter is poor quality, but I could be wrong. Good luck to you and if you find out what's happening, it would be nice to hear from you again.

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  7. hi imre!.im impressed with your approach ,simple and easy to grasp.
    i have the Hoya R72 fitted in a PAnasonic FZ40/45 and a Nikon D 60.with the pana,i can frame ,compose and set my setting with the filter fitted.the viewfinder is just bright.on the other hand,the nikon struggles as it is a lil dark that i can;t even tell what my subject is.. does it means that the panasonic is more responsive to IR light? and that it's good for screwed IR filters?I'm going to send my nikon to the philippines ti have it converted and fitted with a goldie pro or,t a full IR glass.my pictures are still not processed since i dont have an imaging processing software.all i is a slightly enhance pics coming from my manufacturer's software,View NX
    thanks and i hope you can enlighten me on this.your sots are great...i love them.

    venerandobuot@gmail.com

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  8. in my experiment with my panasonic FZ 45,ANYTHING faster than 1 sec,it started to get dark.at 10 and 15 sec,it was better exposed.

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  9. What nm number do you use? I bought a 1000nm and it is needing a 1 min exposure in bright light with snow covered ground. I know it wont give me the best results, as no leaves or grass makes for a horrible IR shot. I am feeling like the 1000nm is way too strong. I really liked the episode 24 edits you had so I was thinking perhaps the nm may be too much for what I really want. It would be nice to shoot outside of f2.8 and 1 min exposure.
    thank you in advance.

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    Replies
    1. Hi, Rob. Generally speaking, from what I have learned, it does appear that the 1000nm filter might be cutting out too much near IR light as most sensors usually don't pickup that far into the IR spectrum. I personally have/use a Hoya R72 which cuts at 720nm; it actually lets in a tiny amount of visible light too. In addition, since I'm using an Olympus camera, I've read their sensors are fairly sensitive to near IR light, so that might also help in regard to why the camera can achieve such quick shutter speeds in comparison to some other camera models.

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    2. thank you! I think I will give a 720nm filter a try. I'm not too beat up about it because I am just testing and learning IR, so I'm starting with some cheap ebay filters for about $15-$20 each.

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