A lone coconut tree along Kemasik Beach, Terrenganu, Malaysia. EXIF: f/3.5, 3.2 seconds, ISO 100
So, you’ve heard all the hoo-hah about infrared (IR) photography. You ask, “What is it really all about?” That’s when this tutorial comes in – I will give you a brief walkthrough of the basics of infrared photography, move on the how to capture an infrared photo and finally, the post-processing part.
Note: This guide is written solely with dSLR users in mind, or those having cameras that have threads to screw filters on, allow you to set a custom white balance and have manual mode.
The rest of the tutorial is after the jump. It’s quite long, and so grab a coffee and let’s get started!
Introduction: What is infrared photography?
Photography is also affectionately known as ‘painting with light’. Basically, infrared photography involves painting a scene with infrared – or at least, far red – light that is not visible to the human eye. This quirky way of photographing a scene, person or object yields interesting results – one of the more popular one is the Wood Effect, where foliage glows brilliant white in your infrared photo due to the way they reflect infrared light.
An infrared photograph is not a heat map – not even close. We’re onln capturing infrared light of the wavelength between 700 and 900 nanometers. Your camera is manufactured in such a way that it only allows light in the visible wavelength to fall on its sensor, thus making the scene to resemble as closely as to what the human eye perceives. However, the sensors are somewhat sensitive to infrared light too, and this forms the basis of infrared photography.
As simple as I can put it, infrared photography involves blocking out almost all light from the visible wavelength from reaching the camera sensor, while only allowing infrared light and beyond to reach your camera sensor. Therefore, an infrared (or far red)Â filter is absolutely necessary if you would like to dive head first into the world of infrared photography.
The preparation
Warning: Do not proceed to the purchase of your first infrared filter before finishing this section.
We’ve gone through all the technical aspects of infrared photography. Now the excitement begins – how are we going to do it with your camera. For this part, I’ve taken the consideration of the many builds and models of cameras available on the market, so I will try to make things as general as possible, so that it’s also applicable to your camera. However, this guide is meant to be for dSLR users only. There are other guides on the Internet that helps you to capture infrared photos using point-and-shoot cameras as well as those that you can’t screw a filter on, but for this guide, I’ll only be covering dSLRs due to the easy of use.
Here is an awesome guide for users who own digital point-and-shoot camera and those who need to make their own IR filter – Take Infrared Pictures With Your Digital Camera by Instructables.
Just for you to know, to other Sony Alpha users out there, you don’t have to go through the first few steps if you really do not want to, since I’m an A200 user and it can take infrared photographs. So do A100 and A700. A highly recommended fail-safe way to check whether your camera model supports infrared photography (and lenses that are compatible or incompatble with infrared) is to do a quick Google search. Most probably you will find your way into a Flickr forum where users are very helpful. Make sure you do your homework before investing in a filter!
Checking IR Sensitivity
The first thing you will need to do is to check whether your camera is sensitive towards lights of the wavelengths within the infrared range. Your digital camera sensors are by default, sensitive to some degree of infrared as mentioned previously. Since different manufacturers uses different filters to block out the unwanted/undesirable (at least in the manufacturer’s sense) infrared, your camera’s sensitivity towards infrared will definitely differ.
A common source of infrared light in a household will be the one from your remote control, which sends pulses of infrared light to a receiver (e.g. on your TV set) to execute certain commands. Increase the size of the aperture until it’s at its largest – the smaller the f-value, the larger the aperture is. Increase the shutter speed of your camera to around 1 second. A good tip will be to rest your camera on a table while you place the remote control directly in front of the camera. Set a countdown timer and wait the shutter closes. This is what you should be getting:
The Remote Control Test is used to check whether your camera is sensitive towards infrared light. EXIF: f/3.5, 0.5 seconds, ISO 400
If you see a very dim light, increase the exposure time gradually. If you’re still getting an extremely faint, almost non-existent purple light at 10 seconds, you’re probably out of luck.
Problems with hot spots
Hot spots in infrared photograph usually appear to be, well, a bright, bleached spot near the center of the photo. In some rare cases, there may be a hot band – be it vertical or horizontal, across your photo. Photographers speculate that hot spots are caused by the different refractive index of the optical lenses in the innards of the camera, the near-infrared incompatible coating on the lenses or a combination of both. Other atypical reasons may be a ‘leaky’ camera body, in the sense of light leeching into the camera body due to poorly sealed gaps. Usually this is not a problem in dSLRs.
Before you fork out big bucks for a decent IR filter, here’s one note of caution – most kit lenses that come with your camera may have problems photographing infrared light. Here is a rather comprehensive list of IR compatible and incompatible lenses belonging to the Canon/Nikon system – IR and Lenses by Gisle Hannemyr. The Sony lens that I am current using is 18-70mm f/3.5-5.6. It does produce an unsightly hot spot when the exposure time extends beyond 15 seconds, but below that it is barely noticable.
Other tips to avoid getting a hotspot:
- Try not to shoot into the light source, e.g. the sun, bright lamp or etc.
- Use the largest apreture permissible by the scene or situation. Hot spots get increasingly significant as your aperture size closes in, i.e. large f-number.
- Use a lens hood at all times. Reduces glare from surrouding bright objects or reflective surfaces.
Getting the infrared filter
Make sure that you’ve finished reading the previous section before proceeding!
For starters, I highly recommend you buying the Hora R72 filter – the ‘R72′ denotes that it blocks off all lights with wavelenghts 720 nanometers and below. Note the diameter of the front element of the lens where you will screw the filter on. It is different from the focal length of the lens (e.g. 18-70mm is not the diameter of your lens). If in doubt, consult the engraved/printed words on the inner surface of your lens cover. You might want to try screwing on the filter onto your lens if you’re purchasing it in person.
Hoya R72 is one of the more affordable choices of infrared lenses, and since it cuts off at 720nm (the visible light spectrum ranges from 400nm to 790nm), it allows some red light to enter the sensor. This is especially useful for cameras who have strong infrared blockers or if you’re unsure of the infrared sensitivity of your camera (which you shouldn’t be).
Lateral view of the Hoya R72 filter (55mm), tilted backwards.
Front view of the Hoya R72 filter (55mm). Note that it is 99.9% opaque.
Warning: Watch out of sellers trying to trick you into purchasing a red filter. Do not get lured by low prices, and be sure to double check the filter. The Hoya R72 filter appears to be opaque but when you hold it up against a bright light source, you’ll see a tinge of deep, dark red. For those cheap red filters, they permit visible light to pass through and so, will have a certian degree of transparency.
The price range of a Hoya R72 filter should be around USD30 to USD50. I bought mine at a rather hefty price of SGD90 (approx. USD60) without doing much research on the market price, so be sure that you don’t repeat my mistakes. For those who are intending to purchase through eBay, do check the terms and conditions of the seller (in case of a wrong filter was sent or etc).
Well, that covers the filter part. Return to this section when you’ve finally got your hands on that lovely thing!
Okay, you’re good to go: Hands on
Here is a checklist of things that you will need for your very first infrared shot – a sturdy tripod (please, don’t trust your hand or any photographer’s brace, unless absolutely necessary), your infrared filter and of course, your camera. You might want to bring along a remote shutter controller if you want to minimize camera shake and avoid waiting for the self timer countdown.
Note: It is highly recommended that you star the hands-on activity on a bright, clear day. The luminance of a warm afternoon will be around 100,000 lux, which will reduce the exposure time for you to get an infrared photo significantly.
Getting your camera ready
Some homework needs to be done before your first photography. Get a tripod and scoot over to a patch of green foliage – personally, I’d pick a patch of green grass. Do not screw the infrared filter on yet. Make sure that almost the entire frame is filled up – or at least, half – and make sure the green patch of grass is centered. Check your camera menu, and under White Balance settings, select “Custom White Balance”. Your camera will then instruct you to take a photo of the scene – now then you screw on the infrared filter. Switch to manual mode, maximize the aperture size (smallest possible f-number) and set the shutter speed to around five to ten seconds. Depending on the exposure of the photo, you might want to vary the shutter speed to get the optimum exposure.
For some cameras, including my Sony A200, will give an error message after the photo used for custom white balance was taken. Do not panic – nothing is wrong. Simply ignore the error message. The custom white balance settings are already stored – it’s just that the colour of the scene is too off normal.
Note: You might want to perform this step everytime you shoot (especially when lighting conditions change). If you’re like me who generally photographs under hot afternoon sun for the best infrared photos, you will just have to retain the custom white balance settings.
I strongly recommend you to shoot in the highest resolution, at ISO 100, with the largest aperture and in RAW format, so that you retain as much information as possible.
Taking your first photo
Pick a spot where you would want to set up your equipment. Usually I’ll walk around with the tripod fully extended and have the quick release plate screwed tightly onto the bottom of the camera. Do not screw the infrared filter on yet. Just like in the previous step, frame the scene first before screwing the filter on. Switch to manual mode, set timer, check white balance settings, set ISO to 100. Allow the camera to autofocus (most camera will work). Do not focus before attaching the infrared filter – this is due to the difference in wavelength and how the light is refracted in the lens and camera.
When the shutter closes, open up the image and the RAW, unprocessed image should look something similar (hues may vary due to the different custom white balance settings on different camera systems):
Genting Highlands, in infrared. EXIF: f/3.5, 4 seconds, ISO 100
As you can see, even at f/3.5 a huge but indistinct hotspot can be seen in the middle of the image. Most kit lens will probably produce this kind of hotspot in infrared photography, although some may face more serious hotspotting problems.
Check if your photo is properly exposed. Vary the shutter speed as of when needed.
Aftermath: Post-processing
Now you’ve got the photo, we can move on with the post-processing. Post-processing is a highly personal process because I understand that each of us have a unique taste towards a certain kind of feel in the photo. I tend to slant more towards the high contrast, moderate saturation/desaturation, and for infrared photos, I’d prefer the rest to be moderately desaturated except for the sky.
Recover or fill light in RAW
I don’t use RAW to adjust the white balance. We’ll deal with the colours later. Basically I would want to fill light in some dark areas, recover some black from over-exposed surfaces and perhaps increase the contrast or clarity a little. When you’re done with the minor tweaking, open the file in Photoshop.
Dealing with colours
This is by far the trickiest part of infrared photography – nothing looks like after the photo came out. The sky is tinted orange/brown, the photo has a light blue cast over the supposedly white foliage. The first thing you need to do is to use Auto Levels/Tone (depends on which version of PS you’re using), or press [Alt] + [Shift] + [L]. You should get something like this:
After adjusting levels using the "Auto Tone/Level" function.
As you can see, we have gained better contrast after applying the adjustments. Now head over to Channel Mixer. It’s under Image > Adjustments > Channel Mixer. For the output channel, select the Red channel (should be ‘Red’ by default anyway). Under Source Channels, reduce the Red till it’s 0% and then bump up the Blue till it’s 100%. Now switch over to the Blue channel by selecting it from the dropdown list. Then again, under Source Channels, reduce the Blue till it’s 0% and then increase the Red until it’s 100%. At the end of this, we swapped the blue and red channels. Your photo shoud look like this now:
After tinkering with the channel mixer.
Whooops! Looks like the entire photo is tinted blue, and the foliage appears to be pink/red now. It’s okay. Create a hue adjustment layer and increase it by 25, i.e. “+25″. For the saturation, reduce it by 50, i.e. “-50″. This is because yellow has a higher luminance value than red (+25 shift in hue causes red to turn yellow), and so a desaturated yellow will appear brighter and whiter than a desaturated red. I also throw in a curves adjustment layer to increase the contrast:
After changing the hue and desaturating the image, topping up with a curves adjustment.
Looking better now, aren’t we? Usually I’ll use the colour burn brush to add some blue to the sky, further dodge out the whites in the foliage and do some minor adjustments. Here’s my final product:
The final product.
So here it is, your first infrared photo!
Additional resources and galleries
- Smashing Magazine – 40 Incredible Near-Infrared Photos
- Smashing Magazine – 50 Incredible Photography Techniques and Tutorials (scroll down till point #5)
- Instructables – Take Infrared Pictures With Your Digital Camera
- DPanswers – IR and Lenses
Special thanks to Jeff and Chong Yen who showed interest in infrared photography, which spurred me to write this tutorial over a two-month period (yea, I am slow).
If you have any questions or suggestions, feel free to ask or share them in your comment. If you have some infrared photography works, you can also link them up too!
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