Using AE bracketing to reduce noise and improve image detail

Recently I've been shooting with AE bracketing and learning how to use Hugin (which is free and open source) to blend frames. The main purpose was initially to improve the dynamic range when shooting in certain challenging conditions.

However, what I also discovered is that similar to the techniques used in astrophotography there are some really nice benefits to be had with regards to noise reduction and detail. I'll show you what I mean with an example.

This is a single frame (edit: a 100% crop to be exact) from my X-S10 (demosaiced and denoised with Iridium and rendered with a neutral profile from RawTherapee):

And here's an exposure fused from 3 single frames with Hugin (the above frame was one of them) and then post processed to enhance contrast in RawTherapee:

I think this is a very interesting technique, and I am planning to do some more experimentation to see where I can expect diminishing returns with regards to the number of frames. I can already say that there is a further notable improvement in detail and image quality with 5 frames.

Eager to hear if anyone else is using bracketing for this purpose and what your workflows and results are like.

andrerav wrote:

Recently I've been shooting with AE bracketing and learning how to use Hugin (which is free and open source) to blend frames. The main purpose was initially to improve the dynamic range when shooting in certain challenging conditions.

However, what I also discovered is that similar to the techniques used in astrophotography there are some really nice benefits to be had with regards to noise reduction and detail. I'll show you what I mean with an example.

This is a single frame from my X-S10 (demosaiced and denoised with Iridium and rendered with a neutral profile from RawTherapee):

And here's an exposure fused from 3 single frames with Hugin (the above frame was one of them) and then post processed to enhance contrast in RawTherapee:

I think this is a very interesting technique, and I am planning to do some more experimentation to see where I can expect diminishing returns with regards to the number of frames. I can already say that there is a further notable improvement in detail and image quality with 5 frames.

Eager to hear if anyone else is using bracketing for this purpose and what your workflows and results are like.

That image doesn’t look like it would benefit much from exposure bracketing at all, but combining multiple identical images will indeed null out some noise. It’s been my experience though, that motion/alignment artifact problems tend to outweigh any noise reduction benefit you might get from stacking multiple images of a scene like this. A single well exposed RAW typically never presents a noise problem for me, but I can see stacking a very low light static scene, but not something like this.

Maybe you are just using this image to test with but I don't see any reason you would need to stack images for this scene.

All the highlights and shadows are completely controlled and you should be able to shoot with any combination of iso/shutter/aperture you want.

Would be good to see you exif data to see what your settings are to really talk about it though.

Erik Baumgartner wrote:

[...] It’s been my experience though, that motion/alignment artifact problems tend to outweigh any noise reduction benefit you might get from stacking multiple images of a scene like this.

Absolutely, a tripod and a static motive is basically prerequisite for a successful result with this technique, so it definitely has its limitations.

RustyRus wrote:

[...]

Would be good to see you exif data to see what your settings are to really talk about it though.

Sure, here's a SOOC for the base frame with all the EXIF:

andrerav wrote:

RustyRus wrote:

[...]

Would be good to see you exif data to see what your settings are to really talk about it though.

Sure, here's a SOOC for the base frame with all the EXIF:

If you're looking to minimize noise, this SOOC Jpeg suggests your RAW file would be very significantly underexposed for this scene. Increasing sensor exposure would likely improve the signal to noise ratio by quite a bit.

andrerav wrote:

Erik Baumgartner wrote:

[...] It’s been my experience though, that motion/alignment artifact problems tend to outweigh any noise reduction benefit you might get from stacking multiple images of a scene like this.

Absolutely, a tripod and a static motive is basically prerequisite for a successful result with this technique, so it definitely has its limitations.

It’s been my experience that a truly static landscape is a rare thing indeed.

Erik Baumgartner wrote:

andrerav wrote:

Erik Baumgartner wrote:

[...] It’s been my experience though, that motion/alignment artifact problems tend to outweigh any noise reduction benefit you might get from stacking multiple images of a scene like this.

Absolutely, a tripod and a static motive is basically prerequisite for a successful result with this technique, so it definitely has its limitations.

It’s been my experience that a truly static landscape is a rare thing indeed.

So true! If I may digress, here's a recent example where I got caught out by a brewing thunderstorm while fishing: https://www.flickr.com/photos/70091899@N06/52261853574/

I knew I would have to use bracketing to capture the entire dynamic range, so I went big with -2, 0 and +2. If you study the middle-right of the photo, you can see some artifacts in the treetops. I'm not sure if it's due to a shaking camera or shaking trees (or sub-optimal anchor points in Hugin). But overall the end result came out okay, despite the liveliness of the scene and the fact that my tripod was standing on soft moss:P

Here's another example where I just wanted to layer the massive movements in the ocean water: https://www.flickr.com/photos/70091899@N06/51838549896/

In this photo I used a low amount of bracketing, I think it was along the lines of -1/3, o +1/3 or something like that. Regardless, the blending process brought out some interesting structures in the water.

Anyway, these are completely different uses cases for bracketing than what I described in my original post, but they are examples of how bracketing can be used in scenes with lots and lots of movement and still turn out interesting results. Tripod still required though:P

andrerav wrote:

This is a single frame (edit: a 100% crop to be exact) from my X-S10 (demosaiced and denoised with Iridium and rendered with a neutral profile from RawTherapee):

Can I ask why you don't demosaic and denoise with RawTherapee? Dual demosaic (3-pass + fast) is great for RAFs and the denoise is pretty good as well.

chaimav wrote:

andrerav wrote:

This is a single frame (edit: a 100% crop to be exact) from my X-S10 (demosaiced and denoised with Iridium and rendered with a neutral profile from RawTherapee):

Can I ask why you don't demosaic and denoise with RawTherapee? Dual demosaic (3-pass + fast) is great for RAFs and the denoise is pretty good as well.

Agreed, if Raw Therapee made a demosaicing plug-in for Lightroom, I’m pretty sure I’d choose it over X-Transformer (which is also very good). I wouldn’t apply any NR in X-Transformer in any case.

chaimav wrote:

andrerav wrote:

This is a single frame (edit: a 100% crop to be exact) from my X-S10 (demosaiced and denoised with Iridium and rendered with a neutral profile from RawTherapee):

Can I ask why you don't demosaic and denoise with RawTherapee? Dual demosaic (3-pass + fast) is great for RAFs and the denoise is pretty good as well.

Originally I used it with my X-T20 because the demosaicing with X-Transformer gave much better results than RawTherapee on that sensor. I only keep using it with my X-S10 because RawTherapee adds a 30px black bar on the right side of the frame for some reason. Aside from that black bar, I agree that RawTherapee does a better job at demosaicing on the 26mpx sensor.

andrerav wrote:

chaimav wrote:

andrerav wrote:

This is a single frame (edit: a 100% crop to be exact) from my X-S10 (demosaiced and denoised with Iridium and rendered with a neutral profile from RawTherapee):

Can I ask why you don't demosaic and denoise with RawTherapee? Dual demosaic (3-pass + fast) is great for RAFs and the denoise is pretty good as well.

Originally I used it with my X-T20 because the demosaicing with X-Transformer gave much better results than RawTherapee on that sensor. I only keep using it with my X-S10 because RawTherapee adds a 30px black bar on the right side of the frame for some reason. Aside from that black bar, I agree that RawTherapee does a better job at demosaicing on the 26mpx sensor.

Have you tried the latest nightly?

https://github.com/Beep6581/RawTherapee/releases/tag/nightly-github-actions

Changelog of sorts here:

https://rawtherapee.com/2022/07/rawtherapee-5.9-wip-and-project-updates/

chaimav wrote:

andrerav wrote:

Originally I used it with my X-T20 because the demosaicing with X-Transformer gave much better results than RawTherapee on that sensor. I only keep using it with my X-S10 because RawTherapee adds a 30px black bar on the right side of the frame for some reason. Aside from that black bar, I agree that RawTherapee does a better job at demosaicing on the 26mpx sensor.

Have you tried the latest nightly?

https://github.com/Beep6581/RawTherapee/releases/tag/nightly-github-actions

Changelog of sorts here:

https://rawtherapee.com/2022/07/rawtherapee-5.9-wip-and-project-updates/

Hi,

I tried the nightly build linked above just now, and that fixed the black bar issue. Thank you very much! This improved my workflow a lot

andrerav wrote:

chaimav wrote:

andrerav wrote:

Originally I used it with my X-T20 because the demosaicing with X-Transformer gave much better results than RawTherapee on that sensor. I only keep using it with my X-S10 because RawTherapee adds a 30px black bar on the right side of the frame for some reason. Aside from that black bar, I agree that RawTherapee does a better job at demosaicing on the 26mpx sensor.

Have you tried the latest nightly?

https://github.com/Beep6581/RawTherapee/releases/tag/nightly-github-actions

Changelog of sorts here:

https://rawtherapee.com/2022/07/rawtherapee-5.9-wip-and-project-updates/

Hi,

I tried the nightly build linked above just now, and that fixed the black bar issue. Thank you very much! This improved my workflow a lot

Glad it works for you. The next version of RawTherapee is going to be a huge improvement. There have been a ton of improvements the last 2 years, the issue is the main developer who handled releases is somewhat MIA. He pops his head up once in a while then goes dark again. I find the nightly builds extremely stable, so on a personal level its not that big of an issue.

By the way, now that RawTherapee has local adjustments its a gamechanger. They take a bit to wrap your head around as they don't use the concept of brushes, but can still be very selective and are very powerful.