How do I reduce the noise in my IR shots?

[katkami]

(hope this is the right forum for IR questions)

I've been playing around with my Hoya IR filter and my 2 DSLRs. Seems no matter what I do, my pictures get very "noisy". I noticed if I up the ISO, I can get better results, but obviously there's more noise. However, even at 400 ISO, it still gets very gritty.

Take this example (not my best shot but it's a good example of the noise)


Camera: Olympus E-420
Exposure: 4
Aperture: f/10.0
Focal Length: 42 mm
ISO Speed: 400
Exposure Bias: 0 EV
Flash: Auto, Did not fire

Take a look at the hot tub in particular to see what I mean. More examples in my set: Infrared - a set on Flickr

I think I tweaked the white balance settings as well. Then I brought it into photoshop and just swapped the red & blue channels, maybe did a little auto-leveling, and that's it.

So I'm wondering if I should be doing something different when I take the pics, and if not then, Is there a way to clean up these shots in photoshop after-the-fact? I tried blurring them but that didn't help.

Thanks!

[Nicole]

I think you'll probably get better answers over in the technique section because this is actually more of a technique question since you're focused on how to minimise grain, etc.

There are 2 things from your post that I'd recommend. First, shoot with an ISO lower than 400 and you'll get less grain. Try 100 or even 200. Second, try out an actual noise reduction program and that should help too. Something like NoiseNinja, Nik Software's Dfine, NeatImage, or Topaz DeNoise. That should get better results than blurring things.

Unfortunately I don't know much about IR photography, so that's the extent of my help.

[LeeR]

Noise is always a problem in underexposed images and shooting IR is no exception. I have had good luck doing what you are doing by taking two approaches. One is by making images that are as high key as possible. Large areas of white and light colors help reduce the noise effect. Second, I use Noiseware from Imagenomics. It does about the best job I have found of reducing noise though at the cost of a bit of sharpening. I usually run the noiseware and then sharpen for the best effect.
Recently, however, I have heard of a new technique that I have not yet had the chance to try. The technique works a bit like HDR; you take several images of the same scene at the same exposure, then you lay one on top of the other. Then you open the images in PS one separate layers setting the layer opacities to 100% for the base layer, then 50%, 33% and 25%, respectively. (You don't have to have four exposures; for instance, if you only have two then it would be 100% for the base layer and 50% for the top layer.) The technique works on the principal that noise is truly random and that layer in this way should help counteract the randomness.

You may also want to check out a great articile from Graphics.com as well as my own tutorial on IR here.

[katkami]

Thanks for the pointers! Because the IR filter makes everything so dark, I have a tough time balancing the ISO, with my shutter speed & the amount of redness in the pic. The lower I go with the ISO, the longer I need to make the shutter speed or else the pic comes out quite red.

Thanks also for the pointers to the links & software packages, I'll check those out. I'm just a novice. I was hoping there was a "photoshoppy" way of doing the noise cleanup. Multiple exposures is definitely an interesting concept, if it's really random.

[RLucas]

Originally Posted by katkami

Thanks for the pointers! Because the IR filter makes everything so dark, I have a tough time balancing the ISO, with my shutter speed & the amount of redness in the pic. The lower I go with the ISO, the longer I need to make the shutter speed or else the pic comes out quite red.

Thanks also for the pointers to the links & software packages, I'll check those out. I'm just a novice. I was hoping there was a "photoshoppy" way of doing the noise cleanup. Multiple exposures is definitely an interesting concept, if it's really random.

If you are shooting RAW, you can basically reverse the red and green channels to get rid of that red cast. I only use RawTherapee, but there is an RGB slider for each channel, and what I learned is to take the red slider to 0%, and the green slider to 100% in the red channel. Then, move the green slider to 0% and the red slider to 100% on the green channel. Leave the blue channel untouched. Then you can adjust from there. It will give you some of those nice false color tones you see in so many IR images. If you want, you can check out my flickr stream. I have a set of some IR stuff that I was toying with. It will give you an idea of what I was talking about.

[katkami]

Oh I've actually been editing jpg, I hadn't thought to try editing RAW in photoshop. I also have been swapping the red & blue channels, I will try swapping green instead, thanks for the tips!