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Secrets of Digital Photography ISO DeNoise Filter Updated: 10 18 2004 |
High ISO is its own reward.
Also it's own bag of noise.
Sure, you can shoot better in available darkness, but what about the dramatic increase in grain and color noise?
The vast facilities of iNovaLabs has spent no expense to bring you a warrior in the Battle Against Noise (B.A.N.).
It's in the eBooks (DSLR:Nikon D70, Nikon Coolpix, Sony and coming Canon).
Important Note: This Photoshop Action Filter used to be free, and thousands downloaded it from this site during that promotion. Nowadays you will need to purchase one of the eBooks to acquire it.
This filter is designed to do two things.
- Reduce high-ISO color noise artifacts and
- Reduce high-ISO grain
1. It reduces color noise dramatically, but hopefully, invisibly. Meaning that fine color detail is preserved after it runs, but the large-scale clumping of color noise patterns in the Red and Blue channels is reduced A LOT.
2. More importantly, it reduces the "grain" of the high ISO image to a marked degree, producing an image that looks over a full stop less noisy.
And does so while retaining fine detail.
These images from the house, before and after the filter, are 100% size and were shot at ISO 800!
- ISO 800 shots look like about ISO 300 shots.
- ISO 400 shots look like around ISO 150 shots.
- There's more... but you will have to read it at the bottom of this article.
I think it's really at its best with high ISO images, but you can use it on any sort of shot. You can even run it twice or more on the same shot to create a novel effect.
Some subtle low-contrast texture or color areas won't make it through the filter perfectly, but for areas of detail that have reasonable contrast, even fine colors in the details retain their presence.
Check the dark green foliage areas under the window. Notice how the broad areas of similar tonality get smoothed while fine detail is retained. Notice also how the white stucco wall retains its texture. Many strong de-noise Photoshop plug-ins and Actions from other sources would lose that valid texture, making the wall look like smooth plaster.
I still see some grain...
On purpose, it doesn't do away with all the grain. When the algorithm goes that far, the pictures tend to look obviously retouched. Phony looking.
There is a compromise here, and that is the balance between small subject detail, color detail and grain. Future iNovaFX filters will give users the choice to suppress more grain.
Other benefits can be seen when printing the resulting image at reasonable sizes. Reasonable being 6.75 x 9 inch prints for 2 megapixel cameras and 9 x 12 inches with 3 megapixel cameras and 11 x 14.6 inch prints for 5 megapixel cameras.
Cmprsn Artifacts reduced, too...
If the original image were to be shot using Normal or Basic compression, the print will show LESS compression artifacting compared to a non-processed image. This is a Good Thing.
You might be able to see this improvement around contrasty transition areas. Certainly you can see it in the Red and Blue channels when viewed individually. There, the before/after is dramatic!
This 100% size image shows only the Red channel of an ISO 400 image made using Basic compression. Before/After.
Much of the blocky compression artifacting is gone along with quite a bit of the random red noise on the right, yet detail is not compromised.
What to look for: Notice that the original sample on the left looks almost like a magazine page that lets a ghost of the image on the other side of the paper show through? It's in the middle-tone area below the "50". That's really compression artifacting.
Notice how much less there is of that effect on the right? The blotchy stuff is quite diminished. Remember: This is a worst-case channel of a BASIC compressed image seen at an enormous blow up. The print at this scale would have been 27 inches wide.
Thanks to the Beta testers..The version available now is improved. See the Nikon eBook V.6 and Sony eBook V.2. This same Action is available in the newer "DSLR: Nikon D70" eBook.
Users have noticed improvement with ISO 200 and ISO 100 shots as well. Gee, is this the ISO 50 effect people have been searching for?
-iNova
Get the eBooks. DSLR Nikon D70, Coolpix and Sony Advanced Cyber-shot titles available.
We have a secure order page that will allow previous eBook owners to upgrade for low cost, too.
Or you can call direct and order from the publisher by phone or FAX.
Phone:(310) 475 2988 (M-F 9-5 Pacific Time)
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