Some Infrared Testing

I've wanted to get into monochrome infrared imaging for quite a while but this has been one of those projects that keeps getting pushed to the back burner because it wasn't a priority.  Photographing in infrared is challenging with a very unique and distinctive look. 

One of the reasons why I seem to keep pushing infrared photography to the back burner is that environmental and weather conditions must be "just right" for infrared imaging to work well.  You need the right weather conditions, the right environmental conditions, and the right scene for infrared photography.  You also need to use a tripod and infrared filters.  Just getting one good image can require many minutes of getting everything just right and then actually capturing a long exposure image.

The first step toward getting involved in this type of imaging, however, was to see which of my camera bodies were best for this type of imaging.  I finally accomplished this over the past two days.

This wasn't the best time for this type of test (having green foliage is best) but this test did allow me to compare some distinct features of infrared photography.  It would be much easier to accomplish this comparison in the summer when leaves are on the trees and the grass is green though.  Leaves and grass are rendered a bright glowing white in infrared wavelengths creating a ghostly feeling.  On the other hand, buildings are typically rendered unbelievably sharp and clear providing a stark contrast to the glowing ghostly foliage.  At the moment, we are blanketed in snow and there are no leaves on the trees so it is not an ideal time for this little project.  Our big spruce tree did render in a lighter shade though.  Also, blue skies rendering inky black are a good sign of infrared sensitivity so I had that to compare as well.  

I used Hoya R72 Infrared filters for these tests (two different sizes... a 49mm size for my smaller lenses and a 67mm size for my larger lenses).  This filter allows infrared wavelengths above 720nm through to the sensor while cutting almost all visible light below 720nm. 

Here is a comparison collage...

So, here is what I learned from these test images:

Olympus E-500 - I believe this camera with its Kodak CCD sensor is my favorite when it comes to the final product which isn't much of a surprise to me.  This camera produced sharp images and it seems to be very sensitive to infrared wavelengths.  I get inky black skies and sharp foliage.  The downside of this camera is that I have no Live View and this camera tends to clip highlights.  Noise can be a detriment with this old Kodak sensor so I must keep the ISO as low as possible.  Perhaps most importantly as previously mentioned, I must keep an eye on the highlights (expose for the highlights) because this sensor tends to clip the highlights if I'm not careful.  This camera seems to be very sensitive to infrared wavelengths though so that is a good thing when it comes to infrared photography. 

Fujifilm S100FS - I think this camera might be my second favorite camera for infrared imaging.  What little conifer foliage (needles) we have here seems to render very white and I can get sharp results.  Blue skies are very dark too which is great for this type of imaging.  The camera has Live View and it seems to be very sensitive to infrared wavelengths.  This camera does produce a bit of flare around these infrared highlights but I'm still not sure if that is a bad thing or a good thing.  Halation of highlights is a normal function of infrared photography so this flaring might be a good thing in this case and it may actually be the result of higher sensitivity to infrared wavelengths.  Or, the flaring could just be a lens thing.  Either way, it looks "normal" for infrared imaging.

Panasonic G3 - This camera body might become a favorite after more use.  I like the sharpness when using a tripod...  it has Live View...  and it seems to be quite sensitive to infrared wavelengths.  The camera is small which is a plus for my extensive spinal injuries.  I really need some more tests when leaves are on the trees and the grass is green though.  It is worth mentioning that this is my least favorite camera for visible light photography because of significant shutter lag and general quirkiness.  Maybe I should have this camera's sensor converted to dedicated infrared photography?  I rarely use this camera for anything so dedicating it to infrared photography might be useful...  

Fujifilm X30 - Although this camera is a pleasant surprise to be in this list, I think it is currently tied with the Panasonic G3 for infrared imaging falling behind the Olympus E-500 and the Fujifilm S100FS.  Skies aren't quite as inky black as they should be and the foliage isn't quite as white as it should be.  Honestly though, I should do more testing with this camera when leaves are on the trees and the grass is green.  That being said, I still do not think it will do as well as the Olympus E-500 due to its far smaller sensor size.  I also feel that the Fujifilm S100FS is more sensitive to infrared wavelengths so that camera is a better choice for infrared photography.  Right now, it is looking like the Fujifilm X30 is better suited to being a premium compact camera for visible light photography and I am fine leaving it at that.  It is, indeed, as excellent premium compact camera.  

Sony camera bodies - These cameras are close to unusable for infrared photography.  Sony uses very strong IR-cut filters over their sensors.  This makes regular visible light imaging exceptionally sharp but it renders the camera almost useless for infrared imaging.  One of the above sample images shows an image from this camera that I converted from visible light color to a pseudo-infrared monochrome image.  This pseudo-infrared image is nice but it isn't as good as the other sample images from other cameras.  These Sony cameras are my best cameras for visible light landscape imaging and that is where they should be used.  

This little unscientific infrared test is a good example of needing to use the right tool for the job.  You need to understand the strengths and weaknesses of your tools and you need to choose your tools wisely paying attention to these strengths and weaknesses.  Some tools are better suited for specific purposes and infrared imaging is a very specific purpose.  

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After posting the above blog entry, I ended up mounting my Sony a7 on the tripod while I was on a roll with this project this morning.  I knew that this camera was not suitable for infrared photography but I figured it would be a good idea to add some comparison images to this blog entry anyway.  Mostly, I wanted to see what sort of exposures I would need to at least get some sort of infrared image.

It is exceptionally windy today so I didn't bother shooting the big spruce tree that is right outside our living room window.  That tree is in constant motion this morning!  Long exposures on a windy day just produce a big blur-fest.  Instead, I opted to image the mountaintop in the distance and the flowerbox mounted on the living room window.  I also added a pseudo-IR image for comparison (the top right photo)...

First, there is indeed a difference between the infrared image shot with the R72 filter (top left) and the pseudo-IR image that I had converted digitally from a color image (top right).  

You can see some of the glow in the tree branches in the R72 image (top left) but there are no leaves on the trees this time of year.  If there were leaves, then it is pretty obvious that they would have been glowing brightly.  However, in order to get this top left image exposed correctly, I needed an exceptionally long shutter speed while using a high ISO value.  The branches of the pseudo-IR image (top right) are far darker with more contrast which is very unlike how they would appear in infrared images.

The bottom image is a better example image because it is showing that typical infrared glow in the spruce needles.  So, the Sony a7 can capture some infrared wavelengths but it requires very long exposures to collect enough of that infrared light for an image. 

The exposures with the R72 filter on my Sony a7 are very long requiring high ISO values.  These images are approximately 10 stops longer than the examples in the first part of this blog entry using my cameras that are far more sensitive to infrared wavelengths.  Infrared sensitivity with my Sony cameras is rather low and the far longer exposures require that there be no wind at all.  With exposures this long, any slight movement caused by even calm winds will create very noticeable motion blurring.  I suppose that for some images, that might be a nice feature but not for most images.

Actually, with some of the cameras used in the first part of this blog entry, I think I could get some decent images on a bright sunny day just handholding my camera without a tripod.  That is significant.  I would still use a tripod but I could get decent images even without the tripod by increasing the ISO value significantly.  

If I ever purchase a newer model of the Sony a7, this older Sony a7 might be a very good candidate for having the IR-cut filter removed.  I've seen images from a converted Sony a7 and they are spectacular.  This infrared conversion to a dedicated infrared camera that has full sensitivity to infrared wavelengths would eliminate the need for very long exposures.  The full frame sensor, its wide dynamic range, its smooth and deep tonal qualities, and the sharp photos it produces would be a benefit even in dedicated infrared photography.  

In the meantime, I'll use my Olympus E-500 and Fujifilm S100FS for infrared imaging.