Digital Infrared Photography Tutorial

Digital Infrared Photography Tutorial
Very frequently I am emailed by someone who wants to get into infrared photography, has visited my photography online and naturally has several questions to ask.  For years I've been answering those emails individually, but in a better effort to help those out there I've decided to put this tutorial together to cover a lot of what I have learned in the field, and for the primary purpose of helping others get started.  I've tried to break this into the most common questions and topics that one needs to cover.  You can read straight through to the bottom, or jump to each section using the links below....


For anyone interested, more of my work can be viewed and purchased here:
 



How can I tell if my camera will do infrared?

Digital camera sensors are just as sensitive to the infrared spectrum as they are to visible light - the problem is that most manufacturers intentionally try to limit the amount of IR hitting the sensor by placing an IR blocker, also known as an IIRC filter or a hot mirror, in front of the sensor.  So, it very simply comes down to how effective is the IR blocker in your camera?  The reason you want to know this is simple: The better the blocker the longer shutter speeds you will need to get a decent IR exposure through them.  I started years ago with a Nikon D50.  This camera is extremely sensitive to IR.  When I got my Nikon D80, and subsequent D90, I realized that at some point Nikon beefed up the effectiveness of their internal hot mirrors and I don't even bother trying with these cameras using a filter (unconverted).  Yes there have been people out there doing IR with them, but in my experience it is a hassle dealing with the extra long shutter speeds necessary to burn a decent IR exposure through the internal IR blocker.   Just for comparison, with the D50 on a normal sunny day I might be looking at 1/3 second to 2 second exposure times, where the D80/D90 would require 30 seconds to 1 minute for the same exposure.  And in that time, all the leaves on the trees have blown, the clouds have moved - you get the idea.  Much harder to get a sharp image.

So how do you tell if your camera will give you a productive run with IR photography before you spend the cash on an expensive filter?  The best advice I can give is go online to a site like www.flickr.com, find a group for your model camera, join the group, and post the question to the group.  Guaranteed someone in the group has tried it and can tell you their experiences.  The second thing you can do is try the old TV remote test.  This one is simple, your TV remote uses infrared, so aim it at your camera while pushing a button and take a shot.  (Dark ambient light and a longer exposure works best, and on point and shoots or DLSR's with live view this is much easier because you can simply look at the screen and forgo the test shot.)  If you see nothing coming out of the remote in your picture, you probably don't have the best candidate for an IR camera.  if you see a spot of light coming from the front of the remote then you are seeing IR - the brighter the spot the more sensitive your camera is to IR.

I'll end this section with this statement:  All of the above assumes you are going to use an external IR filter on your lens.  If you plan on having a camera converted to IR-only, then throw all this out the window.  Part of the conversion process involves taking the internal IR-blocker out, so at that point any camera that can be converted becomes as sensitive to IR as it previously was to visible light.  I highly recommend conversion over external filters for several reasons that I will get into further down in this tutorial, as well as tell you how and where you can get your camera converted.


Do I have to convert my camera or can I use a filter?

Simple answer is yes you can use a filter and no you don't have to convert your camera.  The picture below was done using a normal visible-light camera and an external IR filter screwed on the front of the lens.



So as you can see it is possible to do extremely effective IR without converting your camera, and in the right situation this can work in your favor.  In the photograph above, notice the smoothness of the water.  this is a result of the 1.6 second shutter speed needed to get this exposure.  At handheld speeds, this smoothness would not exist and in my opinion the shot would lose a lot of its appeal.  



What type of filter should I use?

This is probably the most common question asked of me on a regular basis.  Without going into great detail on the infrared spectrum and wavelength cutoff points, I'll just say that I have used, and prefer, the Hoya R72, or sometimes listed as the RM72.  It cuts off at 720nm, and I think the shots I get from this filter have a lot more flexibility in post-processing than you would get from some of the filters that have higher cutoffs (around 900nm) and yield higher-contrast images.  Simply put, I think you get a great range of tones from this filter and it has been my IR workhorse and has served me well.  I also find it to be one of the more wallet-friendly options.


I also like it because it is of the round, screw-on variety and not a square filter designed for a Cokin type holder.  Don't get me wrong, I am a big fan of Cokin filter setups and use them all the time - but when it comes to infrared I believe that you want to prevent any possible light entering between the filter and the lens, and with the Cokin setups as we all know there is a gap there.  some might debate this point, and there are infrared filters available for Cokin setups that I'm sure people have had success with.  I am just saying that due to the opaqueness of infrared filters I would expect internal reflections between the filter and the lens to at some point be an issue.



Shutter Speed

I have already said that you use longer shutter speeds with filters and quicker shutter speeds with conversions.  Here I will quickly explain why this is the case.  As I mentioned digital cameras have blockers inside designed to filter out the infrared spectrum and prevent it from influencing the appearance of your visible-light photographs.  The strength of these varies, but what they all have in common is a resistance, to some degree, toward IR.  So when exposing an infrared image, to get the image past this blocker and onto your sensor, the longer the shutter stays open the more time the image has to penetrate this barrier and "burn" past it and onto your sensor.  Again I will say that there are some advantages to slower shutter speeds as well as faster ones.  The image below is a great example of what slower shutter speeds will produce:




When you convert a camera to dedicated IR, this blocker is removed and an internal IR filter is installed in its place.  This new internal filter does the opposite of the old one - it lets infrared light right through and blocks visible light from getting to your sensor.  so now your camera only "sees" infrared light and is just as sensitive to it as it once was to visible light.  Because of this, you can once again point and shoot at handheld speeds as you used to with your visible-light camera.   Notice the leaves in the top of this shot - I would be hard pressed to have ever encountered a day calm enough to expose these leaves this sharply using long shutter speeds:






The benefits of conversion and how to convert your camera.

At this point I'll jump right into what I consider to be the most important pros and cons of converting your camera over using an external infrared filter.
 

Conversion Pros:
  • No tripod needed, you can shoot in most cases at handheld speeds
  • No need to buy an expensive IR filter for every lens size you own - the filter is inside the camera so all your lenses will now work for IR
  • You can look through your camera to compose your shots
  • Auto focus will be more accurate
  • Sharper images result from shorter shutter speeds
Conversion Cons:
  • Camera can no longer do visible-light photography
  • Not as easy to create motion effects that can be obtained using longer shutter speeds (though it can be achieved with neutral density filters just as one would use with visible photography)
  • Conversion can be costly, but as far as photography expenses go this one is well worth it.
External Filter Pros:
  • Minimal investment to start off.
  • Camera can also be used for visible-light photography
  • Long exposure motion effects easy to obtain.
External Filter Cons:
  • Can be very expensive (potentially more than conversion) if you own lenses of different diameters and therefore need a filter for each one.
  • Tripod always necessary
  • Cannot see through camera to compose your shots with filter attached (they block visible light, and that's what our eyes use to see).  You will need to remove and replace filter in between each new shot in order to compose.
  • Sharper shots harder to achieve due to longer exposure times
  • Auto-focus will not be as accurate

You could take from this, that if you decide that IR photography is for you then a dedicated conversion is the way to go eventually.  I would agree with this, and would highly recommend the conversion services provided at Life Pixel.  You can find tutorials for performing a partial conversion yourself after ordering the replacement internal filter from them, but I believe it is worth the money to have them perform the service.  the reason I use the term "partial conversion" if you do it yourself is because when Life Pixel converts your camera they do a little more than just replace the internal filter - they perform an auto-focus calibration to compensate for the IR focus shift, set a custom white balance, and above all they know what they are doing and have disassembled hundreds of cameras just like yours.  If the idea of de-soldering components inside your camera makes you nervous, send it to them!

 

I'd also like to do a tiny bit of self-promotion and sincerely ask that if you've found this tutorial helpful, and do decide to convert your camera that you please use the referral banner link above to order your conversion service from Life Pixel.  I'll get a small referral bonus, and you'll sleep well knowing you've helped support a fellow photographer at no cost to you. :)



What time of day and what kind of weather do I need to shoot IR?

 One of the things I like the most about infrared photography is the ability to do it when you wouldn't normally shoot at all.  Most landscape photographers will try to get somewhere by sunrise, and spend the middle of the day with the camera packed away and scouting out a location for sunset.  Infrared reflectivity is the highest when the sun is directly overhead, so the middle of the day is perfect for infrared shooting.  Sure you can get great IR shots when the sun is low on the horizon, and I recommend doing so, but you no longer have to ignore most of the day when the light is horrible for visible-light shooting. 



Since we're on the subject of when and what to shoot, I'd also like to point out that you don't always have to limit yourself to trees and water!  Yes they make great IR subjects, but infrared can also be a wonderful medium for architectural work, especially older,  historical or abandoned buildings...





The focus shift and how to deal with it.

You don't really need to understand the physics of light to understand what's at play here.  Simply put, cameras are calibrated to focus on the visible portion of the light spectrum.  As you travel further away from the visible spectrum and into the infrared spectrum, a slight shift in focus is necessary for your camera to obtain sharpness of your subject.  When you use a conversion service like Life Pixel, they will deal with this for you by calibrating your camera's focusing and this becomes a non-issue.

if you are using filters for your IR photography, I can recommend a couple of techniques to deal with this focus shift:  

First, try to aim your focus point somewhere that you'd consider the average depth of your subject.  Lets keep things simple here and use a tree as an example.  If you're shooting a tree, focus on the trunk.  It is the center-most part of your subject, and right in the middle of what you want to be in focus.  If you were to focus on the part of the tree's canopy closest to you, you are increasing the odds that more of the tree, maybe even the trunk, will be out of focus.  No one will notice if parts of the canopy are not sharp, but a blurry trunk will ruin the shot.

Second, use a smaller aperture (larger f/ number).  Using a smaller aperture increases your depth of field and with IR photography gives you what I like to call your focus margin of error.  The bigger margin of error you give yourself the less throw-away shots you'll end up with when you get back to the computer to review your day of shooting.  (I have punched myself in the face several times over this!)  You don't have to go to extremes - I'd say my typical aperture for IR shooting is anywhere from f/9 to f/18.  I probably never go below f/8.

One BIG tip here: If your camera is equipped with live view, USE IT! When you auto-focus through live view (by using your camera's screen instead of the viewfinder), you remove this issue from the equation. I know, sounds like a wild claim, but think about it: when you use live view to focus your shot, you are focusing on what the sensor sees, not what the lens thinks is sharp - and if it's sharp to the sensor, it is a sharp shot, period. Remember, your lens was designed to focus on the visible light spectrum, not the infrared, so it is not going to compensate - that little "beep beep" that normally tells you your subject is in focus doesnt mean anything when shooting IR


White Balance

Another very frequent question I receive is some form of "I bought an infrared filter and my pictures are completely red.  Why don't they look like yours?"

Yes, infraRED pictures are completely red when using a filter such as the Hoya R72 or any other filter for that matter.  Infrared light is red.  When we see the color red with our eyes, we are seeing the very bottom part of where the infrared spectrum starts, and somewhere around 720 nanometers is where our eyes stop seeing red and the infrared spectrum starts to get into full swing.

"Proper" White Balance Approach:
What you will need to do with your shots is open them up in a program like Photoshop or Camera Raw, or any other software that will let you set a white point, and adjust your white balance to achieve different IR color effects.  Most typically you'll want to select some pixel in the image that represents the brightest part of some foliage (a leaf or grass) in your shot and set it as the white point.  I like to also set a grey point using a shaded area of foliage or grass - this will get your plants, grass and trees the purest white wile leaving most of the color in the shot for your skies.  

Creative White Balance:
You don't always have to set your white balance in this "proper" way - try experimenting by clicking different parts of the image to set white balance.  You'd be surprised how many colors will come out in your otherwise solid-red shot simply by choosing alternate areas of the image to set as your white point or grey point.  The following shots all started as completely red images.  They weren't hand-colored like most people think.  The colors in these shots are solely the result of using a different part of the image as my set point for white balance.


using proper white balance adjustment described above


white balance using alternate parts of the image



Of course you don't always have to shoot color IR and deal with white balance.  You can set your camera to black and white mode if it has one, or convert the red source images to black and white using software.  Black and white is a great look for infrared as well...









How do you get those BLUE skies?


Another common question, and a very simple procedure.  First off, I'm going to describe how to accomplish this using Photoshop, since it is the most common image editing platform out there.  The basis is simple, you are merely performing a swap of the red and blue output channels.


Step 1

Open your red source image in photoshop and set white balance using the "proper" method described above.  You should now have an amber-ish image like this one:




Step2

Go to Image > Adjustments > Channel Mixer
Select the red channel from the Output Channel dropdown, and using the sliders below set red to 0 and blue to 100.
Next, select the blue channel from the Output Channel dropdown and set red to 100 and blue to 0.


You have now swapped the red and blue channels and you should have a blue sky like this:


As with everything in Photoshop there are often many ways to skin a cat - this is the simplest method i know of to perform a channel swap like this.


Thank you
for visiting this tutorial and viewing some samples of my infrared photography.  I sincerely hope you found this helpful or enlightening in any way.  Feel free to send me a message through flickr using any of the image links above if you have any additional questions.
If you feel that this tutorial was helpful and you'd like to contribute to my web hosting fees and my photography in general, feel free to use the button below to donate any small amount through Paypal.  Every dollar helps!

Also as I mentioned before, if you do end up getting your camera converted using the highly recommended Life Pixel service, I would very much appreciate the referral if you order your service from them using the referral link below.  You'd be helping out a fellow photographer at no cost to you, what could be better than that??

 

5 comments:

  1. This comment has been removed by a blog administrator.

    ReplyDelete
  2. What camera are you shooting most of your IR with?

    BTW, great tutorial.

    Don in Everett WA

    ReplyDelete
  3. Thanks for the visit Donald, for the last few years i've been primarily using a converted Nikon D5000

    ReplyDelete
  4. Beautiful work! And which Life Pixel IR filter option do you use?

    ReplyDelete
    Replies
    1. Hi Don, I've used the "Standard IR" conversion each time with LifePixel. In my experience this was really close to the results I was getting with a Hoya 72 IR filter - though the conversion gives you many benefits above using the filter, but the light spectrum captured i feel is about the same. Thanks for the visit!

      Delete