Hot Spots in IR

[Amy Nelson]

When shooting in IR with a smaller mm lens (ie. this example 16mm-55mm @ 19mm) it is common to get Hot Spots in your image, causing a discoloration and lack of detail. But in most cases they are easy to correct in post processing.

In ACR /Light Room you can use either a brush or a radial filter (in this case a radial filter) and full cover the Hot Spot/s. By first adjusting the temperature slider, you can bring the colors closer to match the rest of the image. Then with the uses of the other slider the image can be tweaked to bring the match in closer. Commonly used are increasing Contrast a bit, decreasing Highlights, playing with Shadows, slightly increasing the Whites, and sometimes the Dehaze slider can be a big help. Adjusting the Feathering is a good idea also.

After correction the Hot Spot:

Hopefully you find this helpful!

 

[JimFox]

Very helpful Amy! Thanks so much for this tip.

 

[Douglas Sherman]

Good job, Amy.

 

[JimFox]

As I have been doing more IR hotspot research, it's funny that of the several lists I found listing lenses and whether they were good or bad for hotspots my main 2 lenses were either good for IR with no hotspots or bad for IR with hotspots depending on which list I looked at.

So I guess I need to test them for myself.

For the record the two lenses I use most are Nikon 16-35mm f4 and the 24-120mm f4.

 

[Jim Peterson]

Good work, @Amy Nelson! And I agree with @JimFox RE testing your lenses youself. I have the Nikon 17-35mm f2.8, and I've found it on lists of lenses that are supposedly good for IR. But mine isn't - it gives a distinct, color-shifted hot spot in most IR images I've tried it for.