Noise reduction software in the workflow

I've not used noise reduction software before (Noise Ninja looks useful) but I'm unsure where best to use it in my standard HDR workflow. I know I could apply it after HDR processing, but I would have thought reducing the noise up front would probably give better results.
Here's my current workflow...
1) Save +/- 2 EV RAW (canon .CR2) images.
2) Open them up in P/S elements RAW processor, try to get the optimum settings for all three images and save them as 16 bit digital negatives (.dng) sometimes this might result in > 3 images with better balanced F-stop range.
3) Feed these into Photomatix Pro with whatever options best fit the subject PLUS Photomatix noise reduction and chromatic aberration reduction set.
4) Tonemap and save the output as 16 bit TIF
5) Open in P/S Elements and post-process as necessary, saving as 8 bit TIF, then resizing and sharpen as required for the final output size/destination.

Using something like noise Ninja, I would imagine the noise reduction would occur as part of step 5, but it seems logical that the best results would be had by reducing noise as step 1.5, or next best as step 2.5.

Does anyone have any experience with this sort of thing that they could share?

I'm not sure, but I think if you apply it early, you will lose the benefit of having the extra dynamic range from the RAW/dng files.

I say apply it at the output stage, just prior to sharpening. Sometimes the HDR conversion and tone mapping will remove noise, and sometimes it will introduce it.

Well since I'm just learning photography, and even more lacking in HDR experience, I can only comment that after reading as many HDR tutorials as I can get my hands on, no one has noise removal in their workflow prior to initial HDR creation. Some, StuckInCustoms, doesn't even do noise removal in Photomatix but waits until post-processing. Just what I've read and certainly not to be mistaken for any representation of personal knowledge

Best of luck, Paul

I agree with HDR and Beachside. Hopefully you will get noise reduction in the merge process. You can supplement that on the LDR output with a third party noise reduction. If you use noise reduction prior to HDR, you will introduce artifacts if there is a difference between exposures, or bland featureless areas if the noise is uniform between exposures.
Enough EV range in a HDR conversion will go a long way to reducing color and luminance noise, and reduce sharpness a bit. Clean up noise and touch up sharpness on the output.

DAVE RHUBERG wrote:I agree with HDR and Beachside. Hopefully you will get noise reduction in the merge process. You can supplement that on the LDR output with a third party noise reduction. If you use noise reduction prior to HDR, you will introduce artifacts if there is a difference between exposures, or bland featureless areas if the noise is uniform between exposures.
Enough EV range in a HDR conversion will go a long way to reducing color and luminance noise, and reduce sharpness a bit. Clean up noise and touch up sharpness on the output.

What he said!