Using HDR for shadow noise reduction ONLY.

[torger]

I came across a specific need for HDR, when copying transparancies with a digital camera and a macro lens the dark areas are dense and need often to be pushed in post, making the digital camera noise show.

My plan was to make a virtually noise-free 16 bit TIF with no clipped highlights, but highlights just touching file saturation (65535), leaving as much space for the shadows as possible. A 5Dmk2 cannot do this in one shot (too noisy shadows), so HDR is needed.

I don't want fancy grunge-looking tonemapping. No non-linearity at all, just the same image as a perfectly ETTR exposed single shot, but with much less shadow noise.

The problem seem to be though that HDR software I have tested is poor at merging exposures -- they don't seem to understand that clipped pixels should be 100% ignored, and possibly don't realize that the topmost stops are the least noisy out of a digital camera. I succeed in getting less shadow noise, but highlights always suffer, they get worse than the best non-clipped ETTR shot from the bracketed shots.

Many HDR softwares are also not designed for making it possible to produce neutral results, so I'm kind of stuck. Any ideas?

I've tried picturenaut, sns-hdr, hugin hdrmerge, luminance hdr.

[Ben Rubinstein]

Try Zero Noise

[torger]

Try Zero Noise

Thanks for the tip, seems to what I need, but the software refuse to run (expired), and there's no new version.

[feppe]

I blend manually, google digital blending, you'll get an LL article as the first choice.

For the rare image where digital blending doesn't work well, I use Tufuse Pro, but don't think it's actively developed, either. I think Enfuse might do the same thing, not sure about its status.

[Guillermo Luijk]

Thanks for the tip, seems to what I need, but the software refuse to run (expired), and there's no new version.

Just set any date before 2012 ant it will work.

[torger]

Just set any date before 2012 ant it will work.

Thanks for the tip, I may test it later. With some tweaking I got desired results in the end with SNS-HDR though.

[bill t.]

There was a free PS Action that was floating around the net for quite a while called "Double Dynamics" that implemented a variation of Guillermo's "Zero Noise" concept.

You stacked a (roughly) 2 stop overexposed image on top of an image that was dark enough to just barely be holding on to the highlights.  I recall the action used a blurred selection mask instead of a luminance mask which had the effect of also pumping up the mid range contrast nicely.

Anyway it was quite marvelous for a wide range of high contrast images, and very quick to use.  Unfortunately the URL I have for it has disappeared, and I don't see any alternatives on a Google search.  I have lost it on my system.  Maybe somebody here has it.

[Guillermo Luijk]

There is an easy tutorial by Juan Trujillo to achieve the same as ZN does, with two exposures: Yet another method to reduce noise with two exposures.

I wouldn't recommend to shoot 2EV apart, but 3 or 4EV. Noise improvement is far better.

This is noise improvement 2EV apart on a Canon 350D:


And this is improvement 4EV apart:



Regards

[bill t.]

Beyond the obvious improvement in dark area noise, another great thing about the overall Zero Noise concept is that it produces very wide dynamic ranges without messing up the subtlety in the highlights and bright areas.  You get a very luminous effect if you do it right.

[Hening Bettermann]

> For the rare image where digital blending doesn't work well, I use Tufuse Pro, but don't think it's actively developed, either. I think Enfuse might do the same thing, not sure about its status.

ImageFuser is based on Enfuse, if memory serves me, and I am happy with it. It's combined with Align_image. Very easy to use.

[sniper]

Bill I have the action and double dynamic 2 (don't know what the difference is) if anybody is interested I'll upload them somewhere.
Wayne

[Hening Bettermann]

Yes thank you, I'd like to try it.
Good light - Hening.

[sniper]

Yes thank you, I'd like to try it.
Good light - Hening.

Heres the link if I did this right.

http://www.mediafire.com/?6xmg022f4p7yhks

[Hening Bettermann]

Thank you!