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White Balance for Infrared Photography

September 22, 2017

I haven’t owned a camera since the Nikon D60 that would successfully perform a “preset white balance” when I use my Hoya R72 infrared filter.  I have no intentions to convert any of my cameras into “infrared only” by getting the sensor filter changed.  All I’m after is a decent-looking picture on my camera LCD after I take a shot using the R72.

 

All of the newer cameras screen out infrared light so effectively that regular white-balance measurements don’t work.  My old D50 even let me take IR shots hand-held while using the Hoya R72!

 

If you stick with “auto white balance”, then your IR shots look totally red on your camera LCD.  Yuck.  They’re not much better if you try setting the lowest “Kelvin” white balance (2500K on my D500).  Ditto for using “incandescent” white balance.

 

So, what to do?  I came up with a procedure that “mostly” works to solve this IR-shooting problem. At least I get to see pretty decent images on my camera LCD.

 

My secret procedure involves displaying a special color on my computer monitor, and then setting my camera white balance preset using this displayed color.  I previously published an article here explaining how to create special colors and set your camera white balance using this color.

 

The Hoya R72 leaves your photos with very little blue and green color, but a ton of red. It occurred to me that I should be able to create a color that could counteract this, so that you could set a camera white-balance pre-set without using the Hoya R72 at all.  The following procedure is what I came up with.

 

 

 

Auto White Balance with the Hoya R72.  Yuck.

 

 

The picture shown above is what your camera viewfinder looks like when you select “Auto White Balance”.  It’s really hard to see what’s going on.

 

 

Incandescent White Balance.  A teeny bit better.

 

 

 

2500K White Balance.  Slightly better.

 

 

 

I started working on colors that would emphasize red with much less blue and green, so that I could emulate the color spectrum on my computer monitor.  The spectrum I was after was the same one passed through the Hoya R72 IR filter.

 

 

 

Red 240, Green 64, Blue 52

 

If I displayed the above color on my computer monitor and successfully performed a “preset white balance” against it, then I could use that in my camera while shooting with the Hoya R72.  It turns out that going beyond the colors shown above made my camera stop accepting the color as a “good” white balance preset. 

 

 

 

Preset white balance from R240, G64, B52 screen color with Hoya R72

 

As you can see above, I’m definitely on the right track.  Now, my camera screen shows pictures that make a lot more sense. I still need to post-process these pictures to get better white balance, but at least I’m not seeing red while shooting.

 

I realize that color really has no meaning in infrared.  But I think you would agree that pure red tones definitely aren’t what you want.

 

 

 Post-processed shot.  Used a gray-point to get color closer to what I wanted.

 

As you can see above, I was able to get a workable color pallet from the “R240G64B52” preset color.

 

 

 

 

The “correct” RBGG white balance gains for the Hoya R72 from a D60 file

 

 

 

My goal in getting an optimal white balance preset was to achieve the gain values shown above (the 4 numbers are Red, Blue, Green, Green).  This Nikon D60 file shows the results of a “good” preset, based upon using lawn grass in full sun as a target.

 

When I was trying different computer screen colors to WB preset against, I could never drive the red high enough to get the “0.507” gain before the camera WB preset operation would fail (showing “no good” feedback).  I had to stop at the Red value of 240, instead of driving it to the maximum of 256, and its gain of 0.5649 versus the 0.507 goal.

 

 

Exif data showing the R, B, G, G gain values I obtained

 

 

Nevertheless, I’m now getting greatly improved rear LCD screen feedback on my D500 when I shoot infrared with the Hoya R72 filter and my custom white balance preset using the computer monitor.  By the way, another article I wrote mentions how the D7100 and D610 cameras are terrible for infrared photography, with both having unacceptable internal reflections unless you use the little DK-5 viewfinder eyepiece blocker.  The D500, on the other hand,  is a very good camera for infrared photography, even without using its built-in eyepiece shutter.

 

Many cameras still won't produce a good white balance preset using this procedure, but give it a try.  

 

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