Why won’t my Canon 5D Mark IV produce white foliage with an IR760 filter?
Asked 7/2/2021
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I’m shooting with a Canon 5D Mark IV and an IR760 screw-on filter in strong sunlight, usually with 30-second or longer exposures. The files show the expected red tint, but I can’t get green trees to turn white in post-processing, even after trying white balance adjustments, channel swapping, and other common infrared editing steps in Photoshop and Lightroom. Am I setting white balance incorrectly, choosing the wrong subjects, or could the filter be the issue?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
5y ago
2 Answers
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Typical digital camera sensors natively respond to infrared and ultraviolet in addition to visible light.
Because this is not what most people want, a filter is placed in front of the sensor when the camera is built. It excludes infrared and ultraviolet frequencies. This type of bandpass filter is sometimes called a “hot mirror.”
To capture the infrared (or UV) spectrum the hot mirror bandpass filter must be removed. This requires camera disassembly.
Once the bandpass hot mirror has been removed, the sensor will be “full spectrum” and respond to UV, visible, and IR frequencies.
Sometimes an IR filter will be added back in place of the bandpass hot mirror that was removed. If not an IR filter can be used on the lens. Either way, the camera will then respond to infrared frequencies only, and provide the pictures we associate with IR photography.
Without removing the bandpass hot mirror, the camera will not respond to infrared.
There are many companies offering conversion services to make a camera work with infrared.
Depending on mechanical skill and patience, it might be possible to do the conversion yourself. There are videos on the internet for various camera models.
Originally by user95237. Source · Licensed CC BY-SA 4.0
user95237
5y ago
0
Generated from our catalog & community — verify before relying on it.
The most likely issue is the camera, not your scene choice or basic processing. A standard Canon 5D Mark IV has an internal IR-blocking filter (“hot mirror”) over the sensor, which greatly reduces infrared light. That’s why unconverted cameras need very long exposures with an external IR filter, and they often won’t give the strong classic IR look you expect.
To get reliable infrared results, the camera usually needs to be converted by removing the hot mirror. It can then be made full-spectrum or fitted with an internal IR filter. Without that conversion, a screw-on 760nm filter may still record some IR, but the effect is limited and harder to process into bright white foliage.
So you’re probably not doing anything fundamentally wrong in post. The IR760 filter itself is not necessarily bad; the bigger limitation is that the camera is still blocking most IR before it reaches the sensor.
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UniqueBot
AI5y ago
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