Increased Noise When Exporting

[btschumy]

I have been trying to process some astro photos in Photo.  With the longer exposures needed, noise is a problem.  I am stacking 10 images to reduce the noise somewhat.  I've also put a Denoise filter over the image to reduce it further.  I have the image looking very nice in Photo, but when I export it the noise becomes much worse (intolerable).  How can I export something that look what I see onscreen in Photo?

I've tried various export options and nothing seems to help.  Surely this must be possible.

[lepr]

.

[btschumy]

>|<,

Thanks for the response.  This seems like a pretty big flaw in the implementation.  I want to assess how the entire image looks with respect to noise.  If I have to zoom into "Actual Size" then it is impossible to do this.  The only way I see is to try a noise reduction level and then export the image to see what it looks like.  So much for WYSIWYG.

I don't recall the image editing programs having this issue but maybe Photoshop does too.  I don't normally deal with this level of noise in an image.

Bill 

[John Rostron]

2 minutes ago, btschumy said:

This seems like a pretty big flaw in the implementation.  I want to assess how the entire image looks with respect to noise.  If I have to zoom into "Actual Size" then it is impossible to do this.  The only way I see is to try a noise reduction level and then export the image to see what it looks like.  So much for WYSIWYG.

I would have thought that zooming to 100% to assess your noise reduction is an eminently sensible procedure. You would do the same  to assess sharpening. I cannot see why you would want to do it any other way.

John

[btschumy]

To me it makes sense to optimize the image for how it will be viewed.  Generally that would be scaled down.  I suppose I could change the image size to match what would likely be viewed on a monitor.  Then the de-noise amount should match what I see.

I will play around with this and see what works best for me.  Thanks for the information.

[R C-R]

17 minutes ago, btschumy said:

This seems like a pretty big flaw in the implementation.

It is pretty much unavoidable because at less than 100% the radius of the noise info is unlikely to match the screen resolution, so it would have to be enlarged or otherwise interpolated (which it is) to be even approximately correct visually.

[lepr]

.

[btschumy]

Yes, I had tried that previously thinking it would give me an exportable image similar to what I saw.  Of course, making the pixel layer via "Merge Visible" also shows the increased noise.  However, this is a good way to "preview" what I will get when exporting.  Thanks for the suggestion.

[lepr]

.

[James Ritson]

Live filters, particularly those related to sharpening and noise reduction, will generally need to be previewed at 100% to see their actual effect on the "final" image. This is because Photo uses mipmaps (lower resolution versions of the rendered document view) at lower zoom levels to improve performance—the result of convolution filters like unsharp mask, clarity and the current implementation of noise reduction will render differently when applied to a mipmapped version of the document view as it has fewer pixels. I've not looked at recent 2018 versions of the Adobe apps, but I'm aware that the Camera Raw/Lightroom developer may still have a caveat on the Details panel advising users to preview the sharpening and noise reduction results at 100% or larger—so it is likely these apps use a similar mipmap implementation to improve performance when zoomed out.

There's been some discussion about how to tackle this, but with 1.7 the majority of the filters have been rewritten to support hardware acceleration, and noise reduction in particular now has a new algorithm which is hugely more effective. It's subject to testing, but we believe the rewriting of the filters may negate or at least reduce the difference between rendering at different zoom levels.

 

Also, as you're into astrophotography, I would personally recommend experimenting with the 1.7 public beta which is available now:

Mac: https://forum.affinity.serif.com/index.php?/forum/19-photo-beta-on-mac/

Windows: https://forum.affinity.serif.com/index.php?/forum/34-photo-beta-on-windows/

See the stickied thread at the top. I wouldn't normally advocate using a public beta in anger, but the RAW development and noise reduction are vastly improved and you will probably notice a huge difference with astrophotography. I've been editing wide field astro shots at ISO 6400/12800 and the new demosaicing, noise reduction and rewritten clarity filter are a huge benefit to editing my images. With 1.6, I would previously pre-process the RAW files in other software such as Sony Imaging Edge, but 1.7 is so vastly improved that I'll happily do all the editing exclusively in Photo now.

Hope that helps!

[walt.farrell]

8 minutes ago, James Ritson said:

with 1.7 the majority of the filters have been rewritten to support hardware acceleration,

Does that apply to both Mac and Windows?

[R C-R]

19 minutes ago, walt.farrell said:

28 minutes ago, James Ritson said:

with 1.7 the majority of the filters have been rewritten to support hardware acceleration,

Does that apply to both Mac and Windows?

And how do they work when there is no hardware acceleration support for the installed GPU, like for my iMac with its NVIDIA GeForce GTX 660M?